[Elenco soci]


Volpe Yary

Professore Associato


Università degli Studi di Firenze
yary.volpe@unifi.it

Sito istituzionale
SCOPUS ID: 35197291900
Orcid: 0000-0002-5668-1912



Pubblicazioni scientifiche

[1] Guariento L., Buonamici F., Marzola A., Scorianz M., Volpe Y., Design Automation of Lattice-based Customized Orthopedic for Load-bearing Implants, Computer-Aided Design and Applications, 20(1), 158-173, (2023). Abstract
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This work aims at the development of a streamlined and robust CAD procedure to design load-bearing implants. The methodology used to reach this result is explained in the paper: 3D digital anatomy reconstruction of defective structures of the patient is performed with the help of a statistical shape model; subsequently, a CAD modelling tool based on implicit modelling (i.e., nTopology) is used to implement a repeatable semi-automatic procedure that can be performed by a competent user with little effort and limited manual operations. Once that the main shape of the implant is defined, lattice geometries are generated to improve mechanical properties of the implant. The procedure requires as inputs the reconstructed anatomy of the patient and a series of clinical indications on the type of implant that needs to be designed. The paper discusses the development of the whole procedure; achieved results, which include the application of the whole framework on multiple case studies, are presented. The procedure allows the design of a whole implant in 20 minutes circa.

Keywords: CAD Design Automation | Custom Implant; Additive Manufacturing | Implicit Modelling | nTopology

[2] Mussi E., Servi M., Volpe Y., Facchini F., A Simple Interactive Tool for the CAD Modelling of Surgical Guides for Autologous Ear Reconstruction, Computer-Aided Design and Applications, 20(1), 109-118, (2023). Abstract
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The huge possibilities generated by the introduction of rapid prototyping techniques in the medical field has paved the way for collaborations between physicians and engineers to produce personalized medical devices, tailored to the specific anatomy of the patient. Specifically, in the field of autologous auricular reconstruction, i.e. the reconstruction of the external ear using the patient's costal cartilage, the authors worked towards the development of new patient-specific intraoperative devices, to support the surgeon during the procedure. The surgical guide design was then supported by the development of automated techniques for their modelling. In this work, a new hybrid technique for the CAD modelling of surgical guides is proposed. The idea is not to totally eliminate the intervention of the physician in defining the shape of the surgical guides, but rather to simplify their interaction with design tools. The proposed method is based on the straightforward adaption of a two-dimensional template developed by evaluating various auricular biometric parameters to approximate ear structure. The template is coupled to a parametric automatic procedure that generates the surgical guides' CAD model. The template was created outside of commercial CAD modeling software packages to make the procedure more accessible, and it is managed using a well-designed graphical user interface. With specialized questionnaires to evaluate the surgeon's satisfaction, the interface was put to the test, and the results were positive.

Keywords: 3D Modelling | Autologous Ear Reconstruction | CAD | Microtia | Personalized Medicine | Reverse Engineering

[3] Magherini R., Mussi E., Servi M., Volpe Y., Emotion recognition in the times of COVID19: Coping with face masks, Intelligent Systems with Applications, 15, (2022). Abstract
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Emotion recognition through machine learning techniques is a widely investigated research field, however the recent obligation to wear a face mask, following the COVID19 health emergency, precludes the application of systems developed so far. Humans naturally communicate their emotions through the mouth; therefore, the intelligent systems developed to date for identifying emotions of a subject primarily rely on this area in addition to other anatomical features (eyes, forehead, etc.). However, if the subject is wearing a face mask this region is no longer visible. For this reason, the goal of this work is to develop a tool able to compensate for this shortfall. The proposed tool uses the AffectNet dataset which is composed of eight class of emotions. The iterative training strategy relies on well-known convolutional neural network architectures to identify five sub-classes of emotions: following a pre-processing phase the architecture is trained to perform the task on the eight-class dataset, which is then recategorized into five classes allowing to obtain 96.92% of accuracy on the testing set. This strategy is compared to the most frequently used learning strategies and finally integrated within a real time application that allows to detect faces within a frame, determine if the subjects are wearing a face mask and recognize for each one the current emotion.

Keywords: Artificial intelligence | COVID19 | Emotion recognition | Facial Expression Recognition | Grad-CAM | Non-verbal communication

[4] Magherini R., Mussi E., Volpe Y., Furferi R., Buonamici F., Servi M., Machine Learning for Renal Pathologies: An Updated Survey, Sensors, 22(13), (2022). Abstract
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Within the literature concerning modern machine learning techniques applied to the medical field, there is a growing interest in the application of these technologies to the nephrological area, espe-cially regarding the study of renal pathologies, because they are very common and widespread in our society, afflicting a high percentage of the population and leading to various complications, up to death in some cases. For these reasons, the authors have considered it appropriate to collect, using one of the major bibliographic databases available, and analyze the studies carried out until February 2022 on the use of machine learning techniques in the nephrological field, grouping them according to the addressed pathologies: renal masses, acute kidney injury, chronic kidney disease, kidney stone, glomerular disease, kidney transplant, and others less widespread. Of a total of 224 studies, 59 were analyzed according to inclusion and exclusion criteria in this review, considering the method used and the type of data availa-ble. Based on the study conducted, it is possible to see a growing trend and interest in the use of machine learning applications in nephrology, becoming an additional tool for physicians, which can enable them to make more accurate and faster diagnoses, although there remains a major limitation given the diffi-culty in creating public databases that can be used by the scientific community to corroborate and even-tually make a positive contribution in this area.

Keywords: artificial intelligence | deep learning | machine learning | renal pathology

[5] Lazzeri S., Talanti E., Basciano S., Barbato R., Fontanelli F., Uccheddu F., Servi M., Volpe Y., Vagnoli L., Amore E., Marzola A., McGreevy K.S., Carfagni M., 3D-Printed Patient-Specific Casts for the Distal Radius in Children: Outcome and Pre-Market Survey, Materials, 15(8), (2022). Abstract
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Background: Orthopaedic and Trauma surgery is expected to undergo profound trans-formation as a result of the adoption of 3D technology. Among the various applications, patient specific manufacturing of splints and casts would appear to be, particularly in children, an interesting implementation. This study aims to assess the safety of patient specific 3D casts obtained with a newly developed 3D-scanning devise in a small case series. We therefore conducted a clinical outcome and pre-marketing study in 10 consecutive patients with distal radius fractures treated at an Academic Level I Pediatric Trauma Center. After the application of the 3D cast, patients underwent three consecutive evaluations in the following 21 days. The main outcome measurements were: pain, skin lesions and general comfort, and acceptance of the cast. The three domains were measured with the Visual Analogue Scale (VAS), the NPUAP/EPUAP classification and the Positive affect-Negative affect Scale for Children (PANAS-C), the Self-Assessment Manikin (SAM) clinical psychology tests and a Likert-type five item questionnaire, respectively. A final mechanical analysis of the cast was carried out to confirm product integrity. Results: The results obtained were consistently positive in the investigated domains of general comfort, efficacy of contention and mechanical integrity of the 3D-printed cast as well as in the practicability of the supply chain. Conclusions: This study provides Level IV evidence that patient specific 3D printed casts obtained with a specifically designed software were safe in the management of “buckle” fractures of the distal radius in children. These results encourage to extend the technology to the treatment of more demanding fractures.

Keywords: 3D printing | customized implants | orthopedic device | orthosis modeling | pediatrics | personalized medicine | reverse engineering

[6] Mussi E., Servi M., Facchini F., Furferi R., Volpe Y., Assessment and treatment of pectus deformities: a review of reverse engineering and 3D printing techniques, Rapid Prototyping Journal, (2022). Abstract
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Purpose: Among thoracic malformations, pectus deformities have the highest incidence and can result in a wide range of severe and mild clinical manifestations. Recently, the treatment of pectus deformities is shifting from traditional approaches toward customized solutions. This occurs by leveraging innovative rapid prototyping tools that allow for the design and fabrication of patient-specific treatments and medical devices. This paper aims to provide a comprehensive view of the growing literature in this area to analyze the progress made in this direction. Design/methodology/approach: The search was performed on major search engines through keywords inherent to reverse engineering (RE) and additive manufacturing (AM) technologies applied to pectus deformities and related treatments, selecting 54 papers. These were analyzed according to the addressed pathology, the hardware and software tools used and/or implemented and their integration within the clinical pathway. Findings: First, the analysis led to analyze and divide the papers according to how RE and AM technologies are applied for surgical and non-surgical treatments, pathological assessment and preoperative simulation and planning. Second, all papers were considered within the typical rapid prototyping framework consisting of the three phases of three-dimensional (3D) scanning, 3D modelling and 3D printing. Originality/value: To the best of the authors’ knowledge, to date, no survey has provided a comprehensive view of innovative and personalized treatment strategies for thoracic malformations; the present work fills this gap, allowing researchers in this field to have access to the most promising findings on the treatment and evaluation of pathology.

Keywords: 3D printing | Additive manufacturing | Pectus carinatum | Pectus excavatum | Reverse engineering

[7] Guariento L., Buonamici F., Marzola A., Furferi R., Volpe Y., A Semi-Automatic CAD Procedure to Design Custom-made Surgical Cutting Guides, Computer-Aided Design and Applications, 19(4), 733-740, (2022). Abstract
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The present paper presents the development of a novel procedure for the modeling of Surgical Cutting Guides (SCGs) exploiting an implicit modeling approach. As discussed in the text, this approach allows for a streamlined and efficient design of this type of medical device. A procedural approach based on the application of a series of a priori-known implicit modeling function allows the generation of personalized surgical guides starting from the i) patient’s anatomy and ii) clinical decisions made by the medical staff. The CAD procedure is detailed in the text; achieved results are discussed and compared with a traditional CAD modeling approach on three case studies.

Keywords: CAD | Implicit Modelling | Patient-Specific Instrument | Personalized Medical Device

[8] Mussi E., Simontacchi G., Talamonti C., Servi M., Furferi R., Volpe Y., Protesti L., Carfagni M., Pallotta S., A Rapid Prototyping Strategy for Manufacturing of Personalized Bolus, Lecture Notes in Mechanical Engineering, 209-219, (2022). Abstract
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In radiotherapy, the treatment of skin tumors requires the application of tissue-equivalent devices in order to avoid the skin-sparing effect, and thus maximize and equalize the dose on the target. In the common clinical practice these devices, called bolus, are standard pads that do not perfectly adapt to the geometry of the patient generating empty spaces at the skin-bolus interface. This phenomenon hinders an efficient planning of the dose to be administered due to the non-adherence and the unpredictability of the position of the air gaps. In this work a workflow for the production of patient-specific bolus in Ecoflex® 00–10 silicone rubber (soft, biocompatible and sterilizable material) is proposed. The process exploits modern Reverse Engineering and Additive Manufacturing technologies to guarantee an accurate compliance with the involved geometries. Significant improvement, with respect to flat boluses, in the adhesion of the medical device to the anatomical region were found through in-vitro testing using replicas of the involved anatomy. Repeatability tests of the positioning performed on the customized bolus led to satisfying results demonstrating the possibility of accurate and predictable treatment planning.

Keywords: CAD modeling | Custom bolus | Molding | Radiotherapy

[9] Servi M., Mussi E., Furferi R., Volpe Y., A CAD-Based Tool for Tissue-Mimicking Replica of Human Costal Cartilage, Lecture Notes in Mechanical Engineering, 199-208, (2022). Abstract
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Ear reconstruction surgery is a very demanding intervention for plastic surgeons. The results rely heavily on the “artistic skills” of the surgeon who has the task of creating a three-dimensional sculpture using harvested costal cartilage capable of replicating the shape of a physiological ear. By exploiting a combination of Reverse Engineering, CAD modelling, and Additive Manufacturing tools, it is possible to create efficient and highly personalized simulators to train and support the surgeon before and during surgery. In fact, the flexibility of these techniques allows the development of custom-made medical devices, designed directly on the patient's anatomy. In order to make the simulation as realistic as possible, this work focuses specifically on the creation of accurate costal cartilage replicas, both in terms of geometry and mechanical properties of the material, addressing two aspects: the systematization and automation of the CAD mould modelling procedure and the study of the most efficient mould casting materials.

Keywords: Costal cartilage mould | Ear reconstruction | Medical simulation

[10] Magherini R., Servi M., Mussi E., Furferi R., Buonamici F., Volpe Y., CNN Approach for Monocular Depth Estimation: Ear Case Study, Lecture Notes in Mechanical Engineering, 220-228, (2022). Abstract
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The realization of medical devices to assist the surgeon in autologous auricular reconstruction (personalized surgical guides) requires the use of depth maps images obtained from 3D scans of the patient's profile. In order to make the process of ear geometry acquisition and depth map realization faster, more comfortable for the patient and easily accessible by hospital staff, this work proposes a system able to create depth maps from a single RGB image. The proposed approach involves the integration of tools based on convolutional neural networks to build a modular system capable of isolating the ear from the profile, creating the corresponding depth map, and refining it to correct inaccuracies. The system was trained and tested using a database of human profile images and corresponding depth maps made available by the University of Notre Dame. To evaluate the result in this preliminary study, standard metrics such as mean square error and structural similarity were used, yielding results suitable for the targeted application.

Keywords: 3D vision | CNN | Depth map estimation | Ear reconstruction

[11] Mussi E., Servi M., Facchini F., Volpe Y., Furferi R., A rapid prototyping approach for custom training of autologous ear reconstruction, International Journal on Interactive Design and Manufacturing, 15(4), 577-585, (2021). Abstract
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Autologous ear reconstruction is the preferred treatment in case of partial or total absence of the patient external ear. This kind of surgery can be really challenging since precise replication of complex three-dimensional structure of the ear is crucial to provide the patients with aesthetically consistent reconstructed anatomy. Therefore, the results strongly depends on the “artistic skills” of the surgeon who is in charge to carry out a three-dimensional sculpture, which resembles the shape of a normal ear. In this context, the definition of a preoperative planning and simulation process based on the patient's specific anatomy may help the surgeon in speeding up the ear reconstruction process and, at the same time, to obtain better results, thus allowing a superior surgical outcome. In the present work the main required features for performing an effective simulation of the ear reconstruction are identified and a strategy for their interactive design and customization is devised with the perspective of a semi-automatization of the procedure. In detail, the paper provides a framework which start from the acquisition of 3D data from both a healthy ear of the patient (or, if not available e.g. due to bilateral microtia of the ear of one of his parents or from a template) and of costal cartilage. Acquired 3D data are properly processed to define the anatomical elements of the ear and to find, using nesting-based algorithms, the costal cartilage portions to be used for carving the ear itself. Finally, 3D printing is used to create a mockup of the ear elements and a prototype of the ear to be reconstructed is created. Validated on a test case, the devised procedure demonstrate its effectiveness.

Keywords: Additive manufacturing | Autologous ear reconstruction | Microtia | Preoperative planning | Reverse engineering

[12] Servi M., Mussi E., Profili A., Furferi R., Volpe Y., Governi L., Buonamici F., Metrological characterization and comparison of D415, D455, L515 realsense devices in the close range, Sensors, 21(22), (2021). Abstract
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RGB-D cameras are employed in several research fields and application scenarios. Choosing the most appropriate sensor has been made more difficult by the increasing offer of available products. Due to the novelty of RGB-D technologies, there was a lack of tools to measure and compare performances of this type of sensor from a metrological perspective. The recent ISO 10360-13:2021 represents the most advanced international standard regulating metrological characterization of coordinate measuring systems. Part 13, specifically, considers 3D optical sensors. This paper applies the methodology of ISO 10360-13 for the characterization and comparison of three RGB-D cameras produced by Intel® RealSense™ (D415, D455, L515) in the close range (100–1500 mm). ISO 10360-13 procedures, which focus on metrological performances, are integrated with additional tests to evaluate systematic errors (acquisition of flat objects, 3D reconstruction of objects). The present paper proposes an off-the-shelf comparison which considers the performance of the sensors throughout their acquisition volume. Results have exposed the strengths and weaknesses of each device. The D415 device showed better reconstruction quality on tests strictly related to the short range. The L515 device performed better on systematic depth errors; finally, the D455 device achieved better results on tests related to the standard.

Keywords: Active stereo | Depth camera | Device characterization | ISO 10360-13 | LiDAR | Performance comparison | RealSense D415 | RealSense D455 | RealSense L515 | Reverse engineering

[13] Secciani N., Brogi C., Pagliai M., Buonamici F., Gerli F., Vannetti F., Bianchini M., Volpe Y., Ridolfi A., Wearable Robots: An Original Mechatronic Design of a Hand Exoskeleton for Assistive and Rehabilitative Purposes, Frontiers in Neurorobotics, 15, (2021). Abstract
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Robotic devices are being employed in more and more sectors to enhance, streamline, and augment the outcomes of a wide variety of human activities. Wearable robots arise indeed as of-vital-importance tools for telerehabilitation or home assistance targeting people affected by motor disabilities. In particular, the field of “Robotics for Medicine and Healthcare” is attracting growing interest. The development of such devices is a primarily addressed topic since the increasing number of people in need of rehabilitation or assistive therapies (due to population aging) growingly weighs on the healthcare systems of the nation. Besides, the necessity to move to clinics represents an additional logistic burden for patients and their families. Among the various body parts, the hand is specially investigated since it most ensures the independence of an individual, and thus, the restoration of its dexterity is considered a high priority. In this study, the authors present the development of a fully wearable, portable, and tailor-made hand exoskeleton designed for both home assistance and telerehabilitation. Its purpose is either to assist patients during activities of daily living by running a real-time intention detection algorithm or to be used for remotely supervised or unsupervised rehabilitation sessions by performing exercises preset by therapists. Throughout the mechatronic design process, special attention has been paid to the complete wearability and comfort of the system to produce a user-friendly device capable of assisting people in their daily life or enabling recorded home rehabilitation sessions allowing the therapist to monitor the state evolution of the patient. Such a hand exoskeleton system has been designed, manufactured, and preliminarily tested on a subject affected by spinal muscular atrophy, and some results are reported at the end of the article.

Keywords: hand exoskeleton | home assistance | mechatronics design | robotics | telerehabilitation | wearable robot

[14] Buonamici F., Carfagni M., Furferi R., Volpe Y., Governi L., Reverse engineering by CAD template fitting: study of a fast and robust template-fitting strategy, Engineering with Computers, 37(4), 2803-2821, (2021). Abstract
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This paper considers the fitting of a CAD template model to tessellated data as strategy to implement a reverse engineering process that aims at the reconstruction of a parametric associative CAD model. The reconstruction methodology, called Template-Based CAD Reconstruction (TCRT), has been presented and fully discussed in a previous paper Buonamici et al. (J Comput Des Eng 5:145–159, 2018). The present paper focuses on the study of a fast and robust strategy to perform the fitting of the Template CAD Model to reference data. The study explores how different optimization strategies and evaluation metrics can affect a parametric CAD-fitting methodology. Two different optimization algorithms (PSO and GA) and three formulations of the objective function are tested to find the most effective combination. Reconstruction test cases are presented and discussed in the text.

Keywords: CAD reconstruction | CAD template | Fitting | Genetic Algorithm | Particle Swarm Optimization | Reverse engineering

[15] Marzola A., Robilotta C., Volpe Y., Governi L., Furferi R., Statistical Shape Model: comparison between ICP and CPD algorithms on medical applications, International Journal on Interactive Design and Manufacturing, 15(1), 85-89, (2021). Abstract
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The increasing availability of 3D anatomical models obtained from diagnostic images exploiting Reverse Engineering techniques allows the application of statistical analysis in the quantitative investigation of anatomical shapes variability. Statistical Shape Models are a well-established method for representing such variability, especially for complex forms like the anatomical ones. Not by chance, these models are widely used for medical applications, such as guiding segmentation of the diagnostic image and virtual reconstruction of incomplete anatomic region. The application of a statistical analysis on a set of shapes representing the same anatomical region essentially requires that shapes must be in correspondence, i.e. constituted by the same number of points in corresponding position. This work aims to compare two established algorithms, namely a modified version of the Iterative Closest Point and the non-rigid version of the Coherent Point Drift, to solve the correspondences’ problem in the construction of a Statistical Shape Model of the human cranium. The comparison is carried out on the models using the standard evaluation criteria: Generalization, Specificity and Compactness. The modified version of the Iterative Closest Point delivers a better Statistical Shape Model in terms of Generalization and Specificity, but not for Compactness, than the Coherent Point Drift-based model.

Keywords: Computer-Aided Technologies | Correspondences’ problem | Reverse Engineering | Statistical Shape Analysis | Statistical Shape Model

[16] Mussi E., Servi M., Facchini F., Carfagni M., Volpe Y., A computer-aided strategy for preoperative simulation of autologous ear reconstruction procedure, International Journal on Interactive Design and Manufacturing, 15(1), 77-80, (2021). Abstract
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Autologous ear reconstruction is the preferred treatment in case of partial or total absence of the external ear. The surgery can be very challenging to perform and the aesthetic result highly dependent on the surgeon’s “artistic skills”. In this context a preoperative planning and simulation phase based on the patient’s specific anatomy may result crucial for the surgical outcome. In this work, starting from a case study, the elements necessary for an effective simulation are identified and a strategy for their interactive design and customization is devised with a perspective of a semi-automatization of the procedure.

Keywords: Additive manufacturing | Autologous ear reconstruction | Microtia | Preoperative planning | Reverse engineering

[17] Servi M., Buonamici F., Puggelli L., Volpe Y., A new metrological characterization strategy for 3D multi-camera systems, International Journal on Interactive Design and Manufacturing, 15(1), 69-72, (2021). Abstract
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The objective of this study is to establish a new methodology for the metrological characterization of interactive multi-camera systems. In the case of 3D system highly adapted to specific needs the accuracy evaluation cannot be performed using standard state-of-the-art techniques. To this end, the metrological characterization techniques used in the literature were investigated in order to define a new methodology that can be adjusted to each device by making the appropriate modifications. The proposed strategy is adopted for the metrological characterization of a new interactive multi-camera system for the acquisition of the arm.

Keywords: Accuracy assessment | Device characterization | Multi-camera system | Optical device | VDI/VDE normative

[18] Bianchi M., Ridolfi A., Secciani N., Servi M., Volpe Y., Design of an automatic optical system to measure anthropometric hand parameters, International Journal on Interactive Design and Manufacturing, 15(1), 73-75, (2021). Abstract
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Personalized medicine is an effective tool to improve the quality of rehabilitation and treatment for patients with disabilities. This study deals with the development of a low-cost hand scanner for the acquisition of anthropometric measures. The data acquired by the scanner is used, thanks to the developed procedure, to tailor the dimensions of a hand exoskeleton. The exoskeleton is used for assistive and rehabilitation purposes.

Keywords: 3D scanning | Anthropometric measurements | Depth sensor | Hand model | Hand scanner

[19] Servi M., Zulli A., Volpe Y., Furferi R., Puggelli L., Messineo A., Ghionzoli M., Facchini F., Handheld optical system for pectus excavatum assessment, Applied Sciences (Switzerland), 11(4), 1-13, (2021). Abstract
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Disruptive 3D technologies, such as reverse engineering (RE) and additive manufacturing (AM), when applied in the medical field enable the development of new methods for personalized and non-invasive treatments. When referring to the monitoring of pectus excavatum, one of the most common thoracic malformations, 3D acquisition of the patient chest proved to be a straightforward method for assessing and measuring chest deformation. Unfortunately, such systems are usually available in a dedicated facility, can be operated only by specialized doctors with the support of engineers and can be used only with patients on site. It is therefore impossible to perform any routine check-up when the patient is unable to reach the outpatient clinic. The COVID19 pandemic situation has placed even greater restrictions on patient mobility, worsening this problem. To deal with this issue, a new low-cost portable optical scanner for monitoring pectus excavatum is proposed in this work. The scanner, named Thor 2.0, allows a remote diagnostic approach, offering the possibility to perform routine check-ups telematically. Usability tests confirmed the user-friendly nature of the devised system. The instrument was used at the Meyer Children’s Hospital (Florence, Italy) chest-malformations center to treat PE patients. The performed measurements proved to be in line with the current state of the art.

Keywords: Handheld scanner | Intel RealSense | Optical chest index | Pectus excavatum | Telemedicine | Usability test | Vacuum bell

[20] Coletta R., Mussi E., Uccheddu F., Volpe Y., Morabito A., Preoperative planning of spiral intestinal lengthening and tailoring: A geometrical approach, Bioengineering, 8(2), 1-10, (2021). Abstract
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Short bowel syndrome is a pathological condition resulting from extensive resection of the intestine, generally performed due to congenital abnormalities, Crohn’s disease, mesenteric ischemia, or neoplasms. The main consequence of this syndrome is a reduction of intestinal absorp-tion, which causes malnutrition and dehydration. In the most severe cases, specific and complex surgical procedures are requested to manage the syndrome. Such procedures consist of the intestinal lengthening, with lead to an increase of absorptive mucosal surface and intestinal transit time and an overall enhancement of intestinal absorption. One of the most promising surgical procedures is spiral intestinal lengthening and tailoring, which consists of a spiral incision of the intestinal wall and in the elongation longitudinally of the intestine by sliding one flap over the other. The final intestinal lengthening is strictly dependent on a series of parameters, some of which are defined by the surgeon. The present paper proposes a mathematical model, based on patient specific anatomical data, which aims to help the surgeon in defining the optimal parameters for the intervention and in foreseeing its outcomes from the preoperative planning phase. Such a tool can assist the physician in the surgery room by improving the procedure and reducing surgical times.

Keywords: Intestinal failure | Intestinal lengthening | Pediatric | Preoperative planning | Short bowel syndrome | Surgical simulation

[21] Mussi E., Servi M., Facchini F., Furferi R., Governi L., Volpe Y., A novel ear elements segmentation algorithm on depth map images, Computers in Biology and Medicine, 129, (2021). Abstract
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The growing interest in the auricular anatomy is due to two different strands of research: 1) in the medical field it is associated with autologous ear reconstruction, a surgery adopted following trauma or congenital malformations; 2) in surveillance and law enforcement the ear is used for human detection and recognition. Alternative systems of ear analysis can be differentiated for the type of input data (two-dimensional, three-dimensional or both), for the type of acquisition tools (3D scanner, photographs, video surveillance, etc.) and finally for the adopted algorithms. Although the segmentation and recognition of the ear from the face is a widely discussed topic in literature, the detection and recognition of individual anatomical elements has not yet been studied in depth. To this end, this work lays the foundation for the identification of the auricular elements through image processing algorithms. The proposed algorithm automatically identifies the contours of the main anatomical elements by processing depth map images. The algorithm was tested qualitatively and quantitatively on a dataset composed of 150 ears. The qualitative evaluation was performed with the collaboration of medical staff and the quantitative tests were performed using manually annotated ground truth data.

Keywords: Depth map | Ear biometrics | Ear dataset | Ear reconstruction | Ear segmentation | Microtia

[22] Servi M., Mussi E., Magherini R., Carfagni M., Furferi R., Volpe Y., U-net for auricular elements segmentation: A proof-of-concept study, Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 2712-2716, (2021). Abstract
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Convolutional neural networks are increasingly used in the medical field for the automatic segmentation of several anatomical regions on diagnostic and non-diagnostic images. Such automatic algorithms allow to speed up time-consuming processes and to avoid the presence of expert personnel, reducing time and costs. The present work proposes the use of a convolutional neural network, the U-net architecture, for the segmentation of ear elements. The auricular elements segmentation process is a crucial step of a wider procedure, already automated by the authors, that has as final goal the realization of surgical guides designed to assist surgeons in the reconstruction of the external ear. The segmentation, performed on depth map images of 3D ear models, aims to define of the contour of the helix, antihelix, tragus-antitragus and concha. A dataset of 131 ear depth map was created;70% of the data are used as the training set, 15% composes the validation set, and the remaining 15% is used as testing set. The network showed excellent performance, achieving 97% accuracy on the validation test.

[23] Mussi E., Servi M., Furferi R., Governi L., Facchini F., Volpe Y., G-ear: A user-friendly tool for assisted autologous ear reconstruction, Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 2750-2755, (2021). Abstract
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The major breakthroughs in the fields of reverse engineering and additive manufacturing have dramatically changed medical practice in recent years, pushing for a modern clinical model in which each patient is considered unique. Among the wide spectrum of medical applications, reconstructive surgery is experiencing the most benefits from this new paradigm. In this scenario, the present paper focuses on the design and development of a tool able to support the surgeon in the reconstruction of the external ear in case of malformation or total absence of the anatomy. In particular, the paper describes an appositely devised software tool, named G-ear, which enables the semi-automatic modeling of intraoperative devices to guide the physician through ear reconstruction surgery. The devised system includes 3D image segmentation, semi-automated CAD modelling and 3D printing to manufacture a set of patient-specific surgical guides for ear reconstruction. Usability tests were carried out among the surgeons of the Meyer Children's Hospital to obtain an assessment of the software by the end user. The devised system proved to be fast and efficient in retrieving the optimal 3D geometry of the surgical guides and, at the same time, to be easy to use and intuitive, thus achieving high degrees of likability.

[24] Fiorineschi L., Bacci T., Frillici F.S.S., Cubeda S., Volpe Y., Rotini F., Carfagni M., Facchini B., Non-reactive test rig for combustor-turbine interaction studies in industrial gas turbines, Journal of Engineering, Design and Technology, (2021). Abstract
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Purpose: This paper aims to present the design of a particular non-reactive test rig for combustion swirlers and first stage turbine nozzles. The test rig is required for important experimental activities aimed at the optimization of a specific class of gas turbines. Design/methodology/approach: A multi-disciplinary team performed the design process by following a tailored design approach, which has been developed for the specific case. The design outcomes allowed to build a fully functional test rig to be introduced in a test cell and then to perform preliminary experiments about the fluid dynamic behaviour of the turbine elements. Findings: The followed design approach allowed to efficiently perform the task, by supporting the information exchange among the different subjects involved in both the conceptual and the embodiment design of the test rig. Additionally, the performed experiments allowed to achieve a final configuration that makes the test rig a valuable test case for combustor-turbine interaction studies. Research limitations/implications: The study described in this paper is focused on the design of a specific test rig, used for first validation tests. However, the achieved results (both in terms of design and test) constitutes the underpinning of the in-depth investigations to be performed in the next steps of the experimental campaign. Originality/value: To the best of the authors’ knowledge, the present paper is the first one that comprehensively describes the design activity of an experimental test rig for turbine application, also providing indications about the specific methodological procedure used to manage the process.

Keywords: Embodiment design | Fluid engineering | Fluid modelling | Mechanical design | Systematic design | Test rig design

[25] Buonamici F., Carfagni M., Puggelli L., Servi M., Volpe Y., A Fast and Reliable Optical 3D Scanning System for Human Arm, Lecture Notes in Mechanical Engineering, 268-273, (2021). Abstract
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The article discusses the design of an acquisition system for the 3D surface of human arms. The system is composed by a 3D optical scanner implementing stereoscopic depth sensors and by an acquisition software responsible for the processing of the raw data. The 3D data acquired by the scanner is used as starting point for the manufacturing of custom-made 3D printed casts. Specifically, the article discusses the choices made in the development of an improved version of an existing system presented in [1] and presents the results achieved by the devised system.

Keywords: 3D printing | 3D scanning | Arm scanner | Body scanner | Orthoses

[26] Secciani N., Pagliai M., Buonamici F., Vannetti F., Volpe Y., Ridolfi A., A Novel Architecture for a Fully Wearable Assistive Hand Exoskeleton System, Mechanisms and Machine Science, 91, 120-127, (2021). Abstract
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Robotics for Medicine and Healthcare is undoubtedly an important emerging sector of the newborn third millennium. There are many aspects in which this branch of robotics already operates; in this article, the focus will be on the so-called “Robotic assistive technology”. In particular, a novel electromechanical design for an assistive Hand Exoskeleton System is presented here. Since freedom of movement plays a crucial role in making actually usable an assistive device, the main point of innovation of the proposed solution lies in the complete wearability of the resulting system: including mechanics, control electronics, and power supply. From the combination of the authors’ previous experience with the improvements presented in this article comes a fully standalone tailor-made assistive device.

[27] Puggelli L., Furferi R., Volpe Y., Governi L., A low-cost ChArUco-based 3D scanner for cultural heritage, IOP Conference Series: Materials Science and Engineering, 949(1), (2020). Abstract
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In the region of the cultural patrimony, operators use high-resolution orthophotos of paintings for the restoration, monitoring and electronic recording and exhibition purposes. Unfortunately, artworks that are to be restored and/or shown in digital museums are painted on canvas that are far from perfectly planar. Professional documents surrounding an artwork to be preserved in digital collections or museums can therefore be enhanced with information relating to the paintings' 3D structure. This paper proposes both the design of a portable low-cost device that enables the acquisition of 3D geometry of painting and the procedure for triangulation of 3D data. This process uses a set of fiducial markers to set and continuously control the mutual orientation of the laser source and the camera and works accordingly to the principle of laser-camera triangulation.

Keywords: 3D Laser Scanner | Cultural Heritage | Marker Detection | Pose Estimation | Reverse Engineering

[28] Furferi R., Giorgi R., Governi L., Matteini M., Volpe Y., Preface, IOP Conference Series: Materials Science and Engineering, 949(1), (2020).
[29] Guariento L., Buonamici F., Marzola A., Volpe Y., Governi L., Graded Gyroid Structures for Load Bearing Orthopedic Implants, Proceedings of the 2020 IEEE 10th International Conference on "Nanomaterials: Applications and Properties", NAP 2020, (2020). Abstract
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The availability of advanced tools able to model complex geometries along with the relaxing of the constraints related to the manufacturing technologies are heavily transforming the design approach in many fields, including healthcare. The focus of this paper is on the optimization of porous lightweight cellular geometries in the orthopedic implants design: lattice structures have proven to fulfill the biological, mechanical, and technological constraints required in designing load bearing devices. The aim is to collect the information provided by the related literature to describe the effects induced by the selection of parameters designing lattice gyroid structures for orthopedic implants.

Keywords: custom metal implant | design for additive manufacturing | gyroid | metallic lattice structures | triply periodic minimal surface

[30] Servi M., Buonamici F., Carfagni M., Volpe Y., Facchini F., Ghionzoli M., Messineo A., CAD-based automatic modelling of customized cutting templates for Pectus Arcuatum surgical correction, Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 2020-July, 6044-6048, (2020). Abstract
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Pectus Arcuatum (PA) is a congenital chest wall deformity which produces a superior manubrial and sternal protrusion, particularly at the sternal angle. PA surgical correction to reduce the angle of the sternum always includes the removal of bone portion by means of horizontal sternal osteotomies, resection of deformed rib cartilage and finally stabilization of the anterior thoracic wall. Within this process an incorrect assessment of the sternotomy angle during the procedure may lead to the need for bone or cartilage grafts to fill the left voids. This problem has been addressed with a patient-specific cutting template, realized with Reverse Engineering and Additive Manufacturing techniques, which proved to be a key element to simplify the procedure and avoid the occurrence of this type of complications. In this work is presented and validated a procedure that, through common CAD operations, realizes in a completely automatic way the CAD model of the custom cutting template, so as to make non-expert users independent in the realization of the medical device.

[31] Servi M., Furferi R., Santerelli C., Uccheddu F., Volpe Y., Ghionzoli M., Messineo A., Outpatient monitoring of Pectus Excavatum: A Neural Network-based approach, Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 2020-July, 5388-5393, (2020). Abstract
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Pectus Excavatum (PE) is a congenital anomaly of the ribcage, at the level of the sterno-costal plane, which consists of an inward angle of the sternum, in the direction of the spine. PE is the most common of all thoracic malformations, with an incidence of 1 in 300-400 people. To monitor the progress of the pathology, severity indices, or thoracic indices, have been used over the years. Among these indices, recent studies focus on the calculation of optical measures, calculated on the optical scan of the patient's chest, which can be very accurate without exposing the patient to invasive treatments such as CT scans. In this work, data from a sample of PE patients and corresponding doctors' severity assessments have been collected and used to create a decision tool to automatically assign a severity value to the patient. The idea is to provide the physician with an objective and easy to use measuring instrument that can be exploited in an outpatient clinic context. Among several classification tools, a Probabilistic Neural Network was chosen for this task for its simple structure and learning mode.

[32] Buonamici F., Furferi R., Governi L., Marzola A., Volpe Y., Scene acquisition with multiple 2D and 3D optical sensors: A PSO-based visibility optimization, Sensors (Switzerland), 20(6), (2020). Abstract
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Designing an acquisition system for 2D or 3D information, based on the integration of data provided by different sensors is a task that requires a labor-intensive initial design phase. Indeed, the definition of the architecture of such acquisition systems needs to start from the identification of the position and orientation of the sensors observing the scene. Their placement is carefully studied to enhance the efficacy of the system. This often coincides with the need to maximize the surfaces observed by the sensors or some other metric. An automatic optimization procedure based on the Particle Swarm Optimization (PSO) algorithm, to seek the most convenient setting of multiple optical sensors observing a 3D scene, is proposed. The procedure has been developed to provide a fast and efficient tool for 2D and 3D data acquisition. Three different objective functions of general validity, to be used in future applications, are proposed and described in the text. Various filters are introduced to reduce computational times of the whole procedure. The method is capable of handling occlusions from undesired obstacle in the scene. Finally, the entire method is discussed with reference to 1) the development of a body scanner for the arm-wrist-hand district and 2) the acquisition of an internal environment as case studies.

Keywords: 3D scanning | Body scanner | Computer graphics | Optical sensors | PSO | Sensor placement | Visibility analysis

[33] Mussi E., Mussa F., Santarelli C., Scagnet M., Uccheddu F., Furferi R., Volpe Y., Genitori L., Current practice in preoperative virtual and physical simulation in neurosurgery, Bioengineering, 7(1), (2020). Abstract
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In brain tumor surgery, an appropriate and careful surgical planning process is crucial for surgeons and can determine the success or failure of the surgery. A deep comprehension of spatial relationships between tumor borders and surrounding healthy tissues enables accurate surgical planning that leads to the identification of the optimal and patient-specific surgical strategy. A physical replica of the region of interest is a valuable aid for preoperative planning and simulation, allowing the physician to directly handle the patient’s anatomy and easily study the volumes involved in the surgery. In the literature, different anatomical models, produced with 3D technologies, are reported and several methodologies were proposed. Many of them share the idea that the employment of 3D printing technologies to produce anatomical models can be introduced into standard clinical practice since 3D printing is now considered to be a mature technology. Therefore, the main aim of the paper is to take into account the literature best practices and to describe the current workflow and methodology used to standardize the pre-operative virtual and physical simulation in neurosurgery. The main aim is also to introduce these practices and standards to neurosurgeons and clinical engineers interested in learning and implementing cost-effective in-house preoperative surgical planning processes. To assess the validity of the proposed scheme, four clinical cases of preoperative planning of brain cancer surgery are reported and discussed. Our preliminary results showed that the proposed methodology can be applied effectively in the neurosurgical clinical practice both in terms of affordability and in terms of simulation realism and efficacy.

Keywords: 3D casting | 3D printing | Additive manufacturing | Brain | Cancer | Computer aided design | Neurosurgery | Physical simulation | Preoperative planning | Virtual planning

[34] Buonamici F., Furferi R., Governi L., Lazzeri S., McGreevy K.S., Servi M., Talanti E., Uccheddu F., Volpe Y., A practical methodology for computer-aided design of custom 3D printable casts for wrist fractures, Visual Computer, 36(2), 375-390, (2020). Abstract
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In recent years, breakthroughs in the fields of reverse engineering and additive manufacturing techniques have led to the development of innovative solutions for personalized medicine. 3D technologies are quickly becoming a new treatment concept that hinges on the ability to shape patient-specific devices.Among the wide spectrum of medical applications, the orthopaedic sector is experiencing the most benefits. Several studies proposed modelling procedures for patient-specific 3D-printed casts for wrist orthoses, for example. Unfortunately, the proposed approaches are not ready to be used directly in clinical practice since the design of these devices requires significant interaction among medical staff, reverse engineering experts, additive manufacturing specialists and CAD designers. This paper proposes a new practical methodology to produce 3D printable casts for wrist immobilization with the aim of overcoming these drawbacks. In particular, the idea is to realize an exhaustive system that can be used within a paediatric environment. It should provide both a fast and accurate dedicated scanning of the hand-wrist-arm district, along with a series of easy-to-use semi-automatic tools for the modelling of the medical device. The system was designed to be used directly by the clinical staff after a brief training. It was tested on a set of five case studies with the aim of proving its general reliability and identifying possible major flaws. Casts obtained using the proposed system were manufactured using a commercial 3D printer, and the device’s compliance with medical requirements was tested. Results showed that the designed casts were correctly generated by the medical staff without the need of involving engineers. Moreover, positive feedback was provided by the users involved in the experiment.

Keywords: CAD | Cast modelling | Orthosis modelling | Personalized medicine | Reverse engineering

[35] Mussi E., Furferi R., Servi M., Volpe Y., Facchini F., Autologous ear reconstruction: A semi-automatic procedure for patient-specific surgical guides, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 5, (2020). Abstract
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Autologous ear reconstruction, i.e. the reconstruction of the outer ear from autologous cartilage tissue, is a very important surgery considering the psychosocial repercussions of an individual affected by microtia (i.e. the total or partial absence of the outer ear). The execution of this surgery can be very complex due to the unique characteristics of this anatomical region. In order to help the surgeon in the process of cutting and suturing, innovative surgical guides were designed that can transmit information about the shape and size of the anatomy to be reconstructed. This work lays the foundation for the creation of a semi-automatic and easy-to-use tool for the modeling of surgical guides. The goal is to make the hospital staff autonomous in the creation of instruments that can be used in pre-surgical simulation and during surgery.

Keywords: Autologous Ear Reconstruction | Bioengineering | Computer Aided Design | Medical Devices and Equipment | Microtia

[36] Cubeda S., Bacci T., Mazzei L., Salvadori S., Facchini B., Fiorineschi L., Volpe Y., Design of a non-reactive warm rig with real lean-premix combustor swirlers and film-cooled first stage nozzles, Proceedings of the ASME Turbo Expo, 7A-2020, (2020). Abstract
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Modern industrial gas turbines typically employ lean-premix combustors, which can limit pollutant emissions thanks to premixed flames, while sustaining high turbine inlet temperatures that increase the single-cycle thermal efficiency. As such, gas-turbine first stage nozzles can be characterized by a highly-swirled and temperature-distorted inlet flow field. However, due to several sources of uncertainty during the design phase, wide safety margins are commonly adopted, having a direct impact on engine performance and efficiency. Therefore, aiming at increasing the knowledge on combustor-turbine interaction and improving standard design practices, a nonreactive test rig composed of real hardware was assembled at the University of Florence, Italy. The rig, accommodating three lean-premix swirlers within a combustion chamber and two first stage film-cooled nozzles of a Baker Hughes heavy-duty gas turbine, is operated in similitude conditions. The rig has been designed to reproduce the real engine periodic flow field on the central vane channel, also allowing for measurements far enough from the lateral walls. The periodicity condition on the central sector was achieved by the proper design of both the angular profile and pitch value of the tailboards with respect to the vanes, which was carried out in a preliminary phase via a Design of Experiments procedure. In addition, circular ducts needed to be installed at the injectors outlet section to preserve the non-reactive swirling flow down to the nozzles' inlet plane. The combustor-turbine interface section has been experimentally characterized in nominal operating conditions as per the temperature, velocity and pressure fields by means of a five-hole pressure probe provided with a thermocouple, installed on an automatic traverse system. To study the evolution of the combustor outlet flow through the vanes and its interaction with the film-cooling flow, such measurements have been replicated also downstream of the vanes'trailing edge. This work allowed for designing and providing preliminary data on a combustor simulator capable of equipping and testing real hardware film-cooled nozzles of a heavy-duty gas turbine. Ultimately, the activity sets the basis for an extensive test campaign aimed at characterizing the metal temperature, film effectiveness and heat transfer coefficient at realistic aerothermal conditions. In addition, and by leveraging experimental data, this activity paves the way for a detailed validation of current design practices as well as more advanced numerical methodologies such as Scale-Adaptive Simulations of the integrated combustor-turbine domain.

Keywords: CFD | Combustor | Experiments | Gas turbine | Interaction | LES | PSP | RANS | Swirling flow | Turbine

[37] Facchini F., Morabito A., Buonamici F., Mussi E., Servi M., Volpe Y., Autologous ear reconstruction: Towards a semiautomatic cadbased procedure for 3D printable surgical guides, Computer-Aided Design and Applications, 18(2), 357-367, (2020). Abstract
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The autologous ear reconstruction surgery, i.e. the reconstruction of the missing ear anatomy with autologous cartilage tissue in case of partial or complete absence of the auricular region, can be extremely complicated due to the unique shape and size of this anatomical region. Operations of sculpting and carving of the costal cartilage in order to realize the ear reproduction require a high degree of manual expertise and experience from the surgeon. The development of surgical aids that can provide the physician with guidelines during the reconstruction is being studied in the literature. However, state-of-the-art techniques do not represent the optimal solution and only partially help in the reconstruction process. They are based on two-or three-dimensional templates of the target anatomy, providing visual support, yet not helping in the actual reconstruction phase, or, in some cases, by providing active aid but not simplifying the procedure sufficiently. In this context, the option of creating custom cutting guides that could actively assist the surgeon both in the pre-operative planning phase and during the surgery was considered. The proposed approach involves the use of surgical guides adopted for the cutting and reconstruction of the individual anatomical elements involved. Through an iterative process carried out in collaboration with the surgeon the characteristics of the surgical guides have been defined. Subsequently, a method that can be applied systematically to model the cutting guides, ready to be printed with additive production techniques was defined. The procedure was designed with a view to a future semi-automatization of the entire process that could make the physician autonomous in the realization of the patient-specific guides.

Keywords: 3D Ear Templates | Autologous Ear Reconstruction | CAD modelling | Personalized Medicine | Reverse Engineering

[38] Buonamici F., Carfagni M., Furferi R., Volpe Y., Governi L., Generative design: An explorative study, Computer-Aided Design and Applications, 18(1), 144-155, (2020). Abstract
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Generative design tools have recently become an interesting solution to tackle design problems in several technical fields. This article takes into consideration the specific field of mechanical design and aims at describing available generative design solutions capable of dealing with structural optimization problems. The study provides a practical description on the workflow and performances of a specific software system implementing a generative approach for the generation of a set of alternative solutions for a static structural design problem. The software analyzed is Autodesk’s Generative Design, hosted in Fusion 360. The article discusses the functioning of the software and its performances; an enhanced focus on the features oriented to the generation of manufacturable shapes is provided in the text. In order to provide a practical and effective procedure, a literature case study was selected to test the software.

Keywords: Biomimetic Design | CAD | Generative Design | Structural Optimization | Topology Optimization

[39] Meli E., Furferi R., Rind A., Ridolfi A., Volpe Y., Buonamici F., A General Framework for Designing 3D Impellers Using Topology Optimization and Additive Manufacturing, IEEE Access, 8, 60259-60269, (2020). Abstract
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Computer Numerical Control (CNC) milling is still today the elective process for the production of single-piece impellers, as it can reliably produce complex geometries, removing the need for additional manufacturing processes. Nevertheless, Additive Manufacturing is winning more and more ground due to its ability to make components of any geometry that cannot be produced using subtractive techniques. As a result, the use of this technology can eventually be seen as the key to develop high-performance rotor components. In this scenario, the design of 3D impellers does not make an exception. Accordingly, the present paper proposes a general framework for engineered re-design and manufacture of 3D impellers installed on centrifugal compressors by exploiting Topology Optimization and Additive Manufacturing's potential. The procedure investigates also the rotoric component's best configuration for both static and dynamic behavior. Finally, the topology-optimized component is produced with AM through the use of suitable materials that can ensure efficient mechanical efficiency to prove the manufacturability of the entire procedure. To validate the proposed framework, the complete re-design of a 3D impeller of a major Italian-based Oil Gas company is carried out, demonstrating that the re-thinking of the component in terms of Topology Optimization is a straightforward approach to increase the overall performance of the produced rotoric part.

Keywords: 3D impellers | additive manufacturing | design | topology optimization | turbomachinery

[40] Servi M., Furferi R., Volpe Y., Ghionzoli M., Messineo A., Towards a Non-invasive Pectus Excavatum Severity Assessment Tool Using a Linear Discriminant Analysis on 3D Optical Data, Lecture Notes in Mechanical Engineering, 686-695, (2020). Abstract
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Pectus Excavatum (PE) is a congenital anomaly of the thoracic cage, at the level of the sternal-costal plane, which consists of an inward angle of the sternum, in the direction of the spine. Its incidence, equal to 1 in 300–400 people, makes it the most frequent among thoracic malformations. For a proper care of patients suffering from PE, it is essential to monitor the progression of the disease and estimate its severity, in order to follow the course of the pathology over time and define the correct treatment. To this end, over the years, severity indexes, or chest indexes, have been introduced. Among them, in recent years, the so-called optical indices, calculated on optical scans of the patient’s chest, are gaining ground. In fact, the optical scan is faster to apply and prevents the patient from being exposed to radiation. In this work the peculiar morphological features of PE have been examined by extracting various geometric parameters, in order to develop an outpatient support tool for the evaluation of the severity of the pathology and the monitoring of its progression over time. The extracted values have been compared against a ground truth obtained through five independent surveys collected from paediatric specialists. A Linear Discriminant Analysis was performed to determine the accuracy of the classification using the proposed geometric parameters, obtaining positive results.

Keywords: Clinical support | Depth camera | Pectus Excavatum | Severity index

[41] Marzola A., Servi M., Volpe Y., A Reliable Procedure for the Construction of a Statistical Shape Model of the Cranial Vault, Lecture Notes in Mechanical Engineering, 788-800, (2020). Abstract
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The application of CAx tools in surgery is representing a breakthrough for clinical practice, both in terms of effectiveness and costs. Working directly on the patient’s own diagnostic images, this approach provides powerful tools for pre-operative simulation, complex-surgery planning, quantitative evaluation of asymmetry or dysmorphism and for the design of the patient-specific instrumentation. To exploit its full potential, methodologies are being developed to automatize and simplify the existing tools and strategies, in order to make them available also to less experienced CAx users, or directly to the surgeons. With this aim, it is proposed a methodological procedure to automatically create a Statistical Shape Model of the cranial vault starting from a Training Set of pathologically unaffected adult crania. The Statistical Shape Model is useful as a template for a data-driven restoration of the physiological shape of the considered anatomy. The proposed procedure provides a reliable strategy for robust automatic detection of shape correspondence. Not requiring any user intervention, the number of samples in the Training Set can be increased at will to consequently increase the variability, and therefore the accuracy, of the resulting parametric model.

Keywords: CAx | Reverse engineering | Statistical Shape Model

[42] Buonamici F., Carfagni M., Furferi R., Governi L., Volpe Y., CAD Reconstruction: A Study on Reverse Modelling Strategies, Lecture Notes in Mechanical Engineering, 165-176, (2020). Abstract
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Computer Aided reconstruction of mechanical parts nowadays heavily relies on dedicated RE software systems and highly skilled users to be carried out effectively. This paper investigates this scenario in order to identify most limiting factors in the current framework. With this respect, several considerations of general validity are drawn while presenting the problem from a theoretical perspective. A significant test case reconstruction, discussed in depth in the manuscript, is used to provide a practical point of view on real applications and help the reader acquire a hands-on comprehension of the current situation.

Keywords: CAD | CAD reconstruction | Reverse engineering

[43] Furferi R., Mantellassi F., Volpe Y., Design and manufacturing of an innovative triple-layer thermo-insulated fabric, Applied Sciences (Switzerland), 10(2), (2020). Abstract
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Materials used for creating fabrics featuring insulation and thermoregulation are typically made of multi-layer materials consisting of two outer layers and inner padding, traditionally made from goose or duck feathers or even with synthetic materials. In this context, the development of a fabric in which the insulation is carried out directly thanks to the structure of its weave, i.e., where the thermoregulation function is entrusted to one of the yarns (suitably volumized to reduce its density and trap the air) may be an important improvement compared to the state of the art. Accordingly, the present work describes the development of a new kind of triple-layer thermo-insulated innovative fabric (named T4Innovation), in which the thermal insulation is not obtained by means of a padding but rather through the use of appropriate volumized yarns, able to ensure thermal insulation in a reduced thickness. This fabric is manufactured in a single weaving phase, greatly facilitating the subsequent operations of the garment maker. The designed and manufactured fabric was extensively tested to assess its performance. The test demonstrated the effectiveness of such a new class of textile product in terms of thermal performance, which is comparable to the ones of a padded material. Since T4Innovation demonstrates aesthetic properties very close to that of traditional unpadded fabrics, its future commercialization could open new horizons in terms of design, fashion, and style, which are cornerstones of the fashion textile industry.

Keywords: Textile design | Thermoregulation | Triple-layer weaving

[44] Buonamici F., Guariento L., Volpe Y., 3D Digital Surgical Planning: An Investigation of Low-Cost Software Tools for Concurrent Design, Lecture Notes in Mechanical Engineering, 765-775, (2020). Abstract
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Bone tumor resections have to be carefully planned in order to avoid intralesional cuts and thus lower the recurrence rate. Until the present-day bone resections have been performed freehand, using anatomical landmarks as reference points to retrieve planned resection planes over the very patient. Such method is highly prone to failure to the detriment of the patient’s health, in fact survival rate for osteosarcomas is very low, ranging between 20% and 47%. The clinical outcome is highly dependent on the resections’ accuracy; several emerging techniques proved to dramatically increase cutting accuracy, as well as survival rate, in particular Patient Specific Instruments (PSIs) and custom 3D printed metal prosthesis. The main limitation to a massive spread of this method is the large manufacturing time due to a lack of communication between surgeons and engineers about the surgical approach and the design constraints. This paper aims to compare several general-purpose low-cost software and to provide surgeons with an effective and easy to use platform to visually share information in a natural manner with engineers thus providing as many design constraints as possible, speed up the design process and avoid unfeasible results. Two surgeons from Azienda Ospedaliera Universitaria Careggi tested and evaluated a series of software. From this preliminary investigation Forger, a digital sculpting and texture painting application for iOS, resulted as the most user friendly and intuitive application among the test group.

Keywords: Computer aided surgery | Concurrent design | Digital surgical planning | Human computer interaction

[45] Buonamici F., Marzola A., Servi M., Uccheddu F., Volpe Y., Ghionzoli M., Messineo A., Pectus excavatum: a new approach for monitoring cup-suction treatment, IFMBE Proceedings, 76, 746-754, (2020). Abstract
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The introduction of the vacuum bell (VB) for the conservative treatment of Pectus Excavatum (PE) has led to a new non-invasive alternative to thoracic surgery. The VB works by elevating the chest as long as a negative differential pressure is internally assured. In recent years studies have been conducted to validate this type of treatment and to outline its correct use; results show a short-term PE improvement when the device is worn for a minimum of 30 min (twice a day) up to a maximum of several hours a day for 12–15 months. Although the worldwide diffusion of VB devices increases year after year, its ability to lift the chest during treatment with respect to the applied pressure has begun to be evaluated only recently. In this paper, a new instrument for measuring chest elevation during treatment is presented and validated. The proposed system consists of two measurement devices: a commercial instrument for the detection of the negative pressure inside the VB, and a specifically developed optical system for the detection of chest movement. The effectiveness of the proposed system, tested on five paediatric patients, paves the way to the objective definition of an optimised patient specific VB scheme of use.

Keywords: Image processing | Optical measurement | Pectus Excavatum | Vacuum bell

[46] Furferi R., Mussi E., Servi M., Uccheddu F., Volpe Y., Facchini F., 3d acquisition of the ear anatomy: a low-cost set up suitable for the clinical practice, IFMBE Proceedings, 76, 669-678, (2020). Abstract
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The most common clinical treatment for ear deformities or non-congenital abnormalities is the reconstruction of the missing geometry using autologous costal cartilage. The surgical procedure consists in cutting, sculpting and suturing harvested costal cartilage from the patient to recreate an ear shape which is symmetric to the contralateral ear. During chirurgical operation, surgeons needs an accurate 3D template as reference to reproduce the ear. For this purpose, reverse engineering and additive manufacturing techniques can be employed. Specifically, this works aims to develop a reliable, low-cost and user-friendly system, to acquire the healthy ear geometry in clinical environment avoiding head patient’s exposition to radiation (MRI, CT scan). An ideal acquisition setup and device have been selected to achieve accurate results. To this end, a casted model of an ear was created as reference, and the best setup was evaluated by comparing the obtained 3D reconstructions with it. Once the setup has been determined, the anatomies of five volunteers were acquired, to test the methodology on human subjects.

Keywords: 3D model | Ear | Microtia | Photogrammetry | RealSense D415

[47] Furferi R., Guariento L., McGreevy K.S., Mussi E., Parri N., Uccheddu F., Volpe Y., 3d printing-based pediatric trainer for ultrasound-guided peripheral venous access, IFMBE Proceedings, 76, 735-745, (2020). Abstract
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Peripheral venous access is an extremely common procedure, crucial in delivering drugs and collecting blood samples. It is associated to high failure rates, especially when pediatric subjects are involved, due to reduced limb size and low cooperation. Ultrasound can sensibly increase success rates and reduce the time required to perform the procedure, though a specific training is necessary to acquire adequate hand-eye coordination and simultaneously handle needle and probe. Commercially available simulators lack of realistic devices that reproduce anatomy and kinematics of pediatric patients. In this work, an echogenic simulator integrating direct 3D printing and silicone casting is proposed. More specifically, it replicates a five years old upper limb’s anatomy comprising an articulated skeleton, muscle tissues, skin and an integrated blood circuit. The devised simulator shows its effectiveness in terms of acoustic properties, articular kinematics reproduction and haptic feedback. Furthermore, the simulator can be easily customized according to specific training needs thanks to a highly flexible manufacturing process.

Keywords: 3D printing | Echogenic soft phantom | Peripheral venous access trainer | Silicone casting

[48] Buonamici F., Carfagni M., Furferi R., Lazzeri S., Servi M., Talanti E., Volpe Y., Automatic CAD modeling of ventilation holes for 3D printed wrist orthoses, Computer-Aided Design and Applications, 17(2), 325-336, (2020). Abstract
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The present paper presents the study of a semi-automatic CAD technique for the generation of ventilation holes on ABS AM-manufactured arm orthoses. A lighter device, good air and water transpiration and an increased patient’s comfort are the main advantages achievable by introducing openings on plastic casts. The proposed procedure relies on the adaptation of a reference pattern of holes, obtained integrating both structural and functional aspects, to each patient’s cast. The adaptation procedure maps the original pattern, respecting its proportions, on each target orthosis, thanks to a set of reference points automatically extracted. The generation of holes is performed relying on an advanced CAD environment (i.e. Siemens NX), where a series of CAD modeling operations, based on the data extracted by the mapping algorithm, have been studied and tested. The whole procedure has been tested on 5 orthoses to validate its efficacy.

Keywords: Cad | Cast modeling | Orthosis modeling | Personalized medicine

[49] Marzola A., Governi L., Genitori L., Mussa F., Volpe Y., Furferi R., A semi-automatic hybrid approach for defective skulls reconstruction, Computer-Aided Design and Applications, 17(1), 190-204, (2020). Abstract
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In cranioplasty surgery, achieving an effective aesthetic shape restoration of the cranial vault is the most important issue to ensure a proper outcome in terms of social and psychological benefits for the patient. To date, the most advanced approach uses CT/MRI data to reconstruct, in a pre-operative stage, the 3D anatomy of the defective skull in order to design a patient-specific prosthesis. In the last years, several techniques have been proposed to improve the applicability of such approach in the clinical practice, but the analysis of the related literature shows still open issues, due to the wide anatomical variability and complexity of the craniofacial anatomy that needs to be retrieved. With the aim to overcome the State-of-the-Art drawbacks, a new semi-automatic hybrid procedure for repairing unilateral or quasi-unilateral (i.e. a single defect slightly passing the sagittal plane) cranial defects is presented. The novel approach is hybrid because a surface interpolation for filling the hole is used together with a template-based reconstruction guided by the healthy counterpart. The procedure, being landmark-independent and avoiding any patch adaptation, represents a valid alternative for the existing approaches also in terms of user's burden, requiring less time consuming and less cumbersome operations. In addition, a new evaluating technique able to measure the symmetry of the reconstruction as well as the continuity between patch and healthy bone is proposed to test the procedure performance. Several test cases have been then addressed to prove the effectiveness and repeatability of the proposed procedure in reconstructing large-size defects of the skull.

Keywords: CAD | Cranioplasty | Reverse Engineering | Skull Reconstruction

[50] Boccini E., Furferi R., Governi L., Meli E., Ridolfi A., Rindi A., Volpe Y., Toward the integration of lattice structure-based topology optimization and additive manufacturing for the design of turbomachinery components, Advances in Mechanical Engineering, 11(8), (2019). Abstract
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Used in several industrial fields to create innovative designs, topology optimization is a method to design a structure characterized by maximum stiffness properties and reduced weights. By integrating topology optimization with additive layer manufacturing and, at the same time, by using innovative materials such as lattice structures, it is possible to realize complex three-dimensional geometries unthinkable using traditional subtractive techniques. Surprisingly, the extraordinary potential of topology optimization method (especially when coupled with additive manufacturing and lattice structures) has not yet been extensively developed to study rotating machines. Based on the above considerations, the applicability of topology optimization, additive manufacturing, and lattice structures to the fields of turbomachinery and rotordynamics is here explored. Such techniques are applied to a turbine disk to optimize its performance in terms of resonance and mass reduction. The obtained results are quite encouraging since this approach allows improving existing turbomachinery components’ performance when compared with traditional one.

Keywords: additive manufacturing | lattice structures | Topology optimization | turbomachinery

[51] Servi M., Buonamici F., Furferi R., Governi L., Uccheddu F., Volpe Y., Leng S., Facchini F., Ghionzoli M., Messineo A., Pectus Carinatum: a non-invasive and objective measurement of severity, Medical and Biological Engineering and Computing, 57(8), 1727-1735, (2019). Abstract
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To date, standard methods for assessing the severity of chest wall deformities are mostly linked to X-ray and CT scans. However, the use of radiations limits their use when there is a need to monitor the development of the pathology over time. This is particularly important when dealing with patients suffering from Pectus Carinatum, whose treatment mainly requires the use of corrective braces and a systematic supervision. In recent years, the assessment of severity of chest deformities by means of radiation-free devices became increasingly popular but not yet adopted as standard clinical practice. The present study aims to define an objective measure by defining a severity index (named External Pectus Carinatum Index) used to monitor the course of the disease during treatment. Computed on the optical acquisition of the patients’ chest by means of an appositely devised, fast and easy-to-use, body scanner, the proposed index has been validated on a sample composed of a control group and a group of Pectus Carinatum patients. The index proved to be reliable and accurate in the characterization of the pathology, enabling the definition of a threshold that allows to distinguish the cases of patients with PC from those of healthy subjects. [Figure not available: see fulltext.]

Keywords: Index | Optical imaging | Pectus Carinatum | Severity assessment | Three-dimensional

[52] Secciani N., Bianchi M., Ridolfi A., Vannetti F., Volpe Y., Governi L., Bianchini M., Allotta B., Tailor-made hand exoskeletons at the university of florence: From kinematics to mechatronic design, Machines, 7(2), (2019). Abstract
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Recently, robotics has increasingly become a companion for the human being and assisting physically impaired people with robotic devices is showing encouraging signs regarding the application of this largely investigated technology to the clinical field. As of today, however, exoskeleton design can still be considered a hurdle task and, even in modern robotics, aiding those patients who have lost or injured their limbs is surely one of the most challenging goal. In this framework, the research activity carried out by the Department of Industrial Engineering of the University of Florence concentrated on the development of portable, wearable and highly customizable hand exoskeletons to aid patients suffering from hand disabilities, and on the definition of patient-centered design strategies to tailor-made devices specifically developed on the different users' needs. Three hand exoskeletons versions will be presented in this paper proving the major taken steps in mechanical designing and controlling a compact and lightweight solution. The performance of the resulting systems has been tested in a real-use scenario. The obtained results have been satisfying, indicating that the derived solutions may constitute a valid alternative to existing hand exoskeletons so far studied in the rehabilitation and assistance fields.

Keywords: Biomechanical engineering | Hand exoskeleton | Kinematic analysis | Mechanism design and optimization | Mechatronics | Wearable robotics

[53] Furferi R., Governi L., Puggelli L., Servi M., Volpe Y., Machine vision system for counting small metal parts in electro-deposition industry, Applied Sciences (Switzerland), 9(12), (2019). Abstract
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In the fashion field, the use of electroplated small metal parts such as studs, clips and buckles is widespread. The plate is often made of precious metal, such as gold or platinum. Due to the high cost of these materials, it is strategically relevant and of primary importance for manufacturers to avoid any waste by depositing only the strictly necessary amount of material. To this aim, companies need to be aware of the overall number of items to be electroplated so that it is possible to properly set the parameters driving the galvanic process. Accordingly, the present paper describes a simple, yet effective machine vision-based method able to automatically count small metal parts arranged on a galvanic frame. The devised method, which relies on the definition of a rear projection-based acquisition system and on the development of image processing-based routines, is able to properly count the number of items on the galvanic frame. The system is implemented on a counting machine, which is meant to be adopted in the galvanic industrial practice to properly define a suitable set or working parameters (such as the current, voltage, and deposition time) for the electroplating machine and, thereby, assure the desired plate thickness from one side and avoid material waste on the other.

Keywords: Electro-deposition industry | Image analysis | Item counting device | Machine vision

[54] Leng S., Bici K., Facchini F., Volpe Y., Uccheddu F., Furferi R., Governi L., Carfagni M., Ghionzoli M., Messineo A., Customized Cutting Template to Assist Sternotomy in Pectus Arcuatum, Annals of Thoracic Surgery, 107(4), 1253-1258, (2019). Abstract
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Purpose: Pectus arcuatum is an anterior chest wall deformity that requires transverse wedge sternotomy. Determining and delivering the correct cutting angle are crucial for successful correction. This report describes the early clinical experience with a novel cutting template technology able to deliver the optimal cutting angle. Description: From patients’ computed tomographic scans, the optimal cutting angle is obtained using computer-aided design. A template comprising slots tilted at the right cutting angle and a safety block to avoid damaging the posterior periosteum is printed through additive manufacturing. Evaluation: The template allows surgeons to perform a precise wedge sternotomy, safely sparing the posterior periosteum in all patients, without complications. Postoperative chest roentgenograms and clinical photographs demonstrate optimal sternal realignment and cosmetic outcome. In this report, the mean operative time was 110 minutes. All patients were successfully discharged, with a mean length of stay of 4 days. Conclusions: Transverse wedge sternotomy aided by a computer-aided design–devised cutting template may reduce the technical challenge of this procedure, thereby increasing its safety and reducing operative times and hospital stay. Further research on long-term patient outcomes is necessary.

[55] Di Angelo L., Di Stefano P., Governi L., Marzola A., Volpe Y., A robust and automatic method for the best symmetry plane detection of craniofacial skeletons, Symmetry, 11(2), (2019). Abstract
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The accurate location of the mid-sagittal plane is fundamental for the assessment of craniofacial dysmorphisms and for a proper corrective surgery planning. To date, these elaborations are carried out by skilled operators within specific software environments. Since the whole procedure is based on the manual selection of specific landmarks, it is time-consuming, and the results depend on the operators' professional experience. This work aims to propose a new automatic and landmark-independent technique which is able to extract a reliable mid-sagittal plane from 3D CT images. The algorithm has been designed to perform a robust evaluation, also in the case of large defect areas. The presented method is an upgraded version of a mirroring-and registration technique for the automatic symmetry plane detection of 3D asymmetrically scanned human faces, previously published by the authors. With respect to the published algorithm, the improvements here introduced concern both the objective function formulation and the method used to minimize it. The automatic method here proposed has been verified in the analysis of real craniofacial skeletons also with large defects, and the results have been compared with other recent technologies.

Keywords: Cranio-maxillofacial | Feature recognition | Medical imaging | Mid-sagittal plane | Symmetry analysis

[56] Carfagni M., Furferi R., Governi L., Santarelli C., Servi M., Uccheddu F., Volpe Y., Metrological and critical characterization of the intel D415 stereo depth camera, Sensors (Switzerland), 19(3), (2019). Abstract
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Low-cost RGB-D cameras are increasingly being used in several research fields, including human–machine interaction, safety, robotics, biomedical engineering and even reverse engineering applications. Among the plethora of commercial devices, the Intel RealSense cameras have proven to be among the most suitable devices, providing a good compromise between cost, ease of use, compactness and precision. Released on the market in January 2018, the new Intel model RealSense D415 has a wide acquisition range (i.e., ~160–10,000 mm) and a narrow field of view to capture objects in rapid motion. Given the unexplored potential of this new device, especially when used as a 3D scanner, the present work aims to characterize and to provide metrological considerations for the RealSense D415. In particular, tests are carried out to assess the device performance in the near range (i.e., 100–1000 mm). Characterization is performed by integrating the guidelines of the existing standard (i.e., the German VDI/VDE 2634 Part 2) with a number of literature-based strategies. Performance analysis is finally compared against the latest close-range sensors, thus providing a useful guidance for researchers and practitioners aiming to use RGB-D cameras in reverse engineering applications.

Keywords: Active stereo | Depth camera | Device characterization | Performance comparison | RealSense D415 | Reverse engineering | VDI/VDE standard

[57] Puggelli L., Uccheddu F., Volpe Y., Furferi R., Di Feo D., Accuracy assessment of CT-based 3D bone surface reconstruction, Lecture Notes in Mechanical Engineering, 487-496, (2019). Abstract
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3D reconstruction of human anatomy from cross-sectional imaging has recently gained increasing importance in several medical fields thus designating the 3D bones reconstruction accuracy, critical for the success of the whole surgical intervention. The 3D anatomic model quality depends on the quality of the reconstructed image, on the quality of the images segmentation step and on the error introduced by the iso-surface triangulation algorithm. The influence of image processing procedures and relative parametrization has been largely studied in the scientific literature; however, the analysis of the direct impact of the quality of the reconstructed medical images is still lacking. In this paper, a comparative study on the influence of both image reconstruction algorithm (standard and iterative) and applied kernel is reported. Research was performed on the 3D reconstruction of a pig tibia, by using Philips Brilliance 64 CT scanner. At the stage of scanning and at the stage of 3D reconstruction, the same procedures were followed, while only image reconstruction algorithm and kernel were changed. The influence of such selection on the accuracy of bone geometry was assessed by comparing it against the 3D model obtained with a professional 3D scanner. Results show an average error in reconstructing the geometry of around 0.1 mm with a variance of 0.08 mm. The presented study highlights new opportunities to control the deviations on the geometry accuracy of the bones structures at the stage of cross sectional imaging generation.

Keywords: 3D model reconstruction | Accuracy | Computed tomography | Kernel reconstruction

[58] Buonamici F., Volpe Y., Furferi R., Carfagni M., Signorini G., Goli G., Governi L., Fioravanti M., Bamboo’s bio-inspired material design through additive manufacturing technologies, Lecture Notes in Civil Engineering, 24, 809-826, (2019). Abstract
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Bamboo is one of the longest-used organic raw materials in the tropics for a large number of different purposes in the daily lives of human beings. Because of its excellent physical-mechanical properties, in many parts of the world it is widely used as a structural material, especially for the construction of scaffolding and the construction of buildings. The bamboo can be modelled as a composite material, consisting of a of a parenchyma cells matrix, similar to a foam, reinforced by bundles of fibers associated with vessels. The present work aimed to explore the possibility to design a 3D printed biomimetic composite material able of keeping advantages from the bamboo morphological structure. Samples made of PVA, ABS and PVA + ABS were manufactured using Fused Deposition Modelling and tested under compression and bending conditions. The behavior under compression has shown to depend mainly on the material used while in bending the structure has shown important effects leading the sample made of PVA + ABS to have the same performances of much expensive pure ABS.

Keywords: Additive manufacturing | Bamboo | Structure optimization

[59] Mussi E., Furferi R., Volpe Y., Facchini F., McGreevy K.S., Uccheddu F., Ear reconstruction simulation: From handcrafting to 3D printing, Bioengineering, 6(1), (2019). Abstract
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Microtia is a congenital malformation affecting one in 5000 individuals and is characterized by physical deformity or absence of the outer ear. Nowadays, surgical reconstruction with autologous tissue is the most common clinical practice. The procedure requires a high level of manual and artistic techniques of a surgeon in carving and sculpting of harvested costal cartilage of the patient to recreate an auricular framework to insert within a skin pocket obtained at the malformed ear region. The aesthetic outcomes of the surgery are highly dependent on the experience of the surgeon performing the surgery. For this reason, surgeons need simulators to acquire adequate technical skills out of the surgery room without compromising the aesthetic appearance of the patient. The current paper aims to describe and analyze the different materials and methods adopted during the history of autologous ear reconstruction (AER) simulation to train surgeons by practice on geometrically and mechanically accurate physical replicas. Recent advances in 3D modelling software and manufacturing technologies to increase the effectiveness of AER simulators are particularly described to provide more recent outcomes.

Keywords: Additive manufacturing | Autologous ear reconstruction | Computer-Aided Design (CAD) | Costal cartilage | Image-processing | Microtia | Silicone rubbers | Simulation | Training

[60] Secciani N., Bianchi M., Meli E., Volpe Y., Ridolfi A., A novel application of a surface ElectroMyoGraphy-based control strategy for a hand exoskeleton system: A single-case study, International Journal of Advanced Robotic Systems, 16(1), (2019). Abstract
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Robotics is increasingly involving many aspects of daily life and robotic-based assistance to physically impaired people is considered one of the most promising application of this largely investigated technology. However, the World Health Organization reports that, so far, only 10% of people in need can get access to the so-called assistive technology also due to its high costs. This work aims to tackle the aforementioned point presenting an innovative control strategy for a low-cost hand exoskeleton system based on surface electromyography signals. Most of the activities of daily living are, in fact, carried out thanks to the hands while the exploitation of surface electromyography signals represents a non-invasive technique in straightforwardly controlling wearable devices. Although such approach results deeply studied in literature, it has not been deeply tested on real patients yet. The main contribution of this article is hence not only to describe a novel control strategy but also to provide a detailed explanation of its implementation into a real device, ready to be used. Finally, the authors have evaluated and preliminary tested the proposed technique enrolling a patient in a single-case study.

Keywords: assistive devices | control strategy | hand exoskeletons | Surface EMG | wearable robotics

[61] Carfagni M., Facchini F., Furferi R., Ghionzoli M., Governi L., Messineo A., Uccheddu F., Volpe Y., Towards a CAD-based automatic procedure for patient specific cutting guides to assist sternal osteotomies in pectus arcuatum surgical correction, Journal of Computational Design and Engineering, 6(1), 118-127, (2019). Abstract
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Pectus Arcuatum, a rare congenital chest wall deformity, is characterized by the protrusion and early ossification of sternal angle thus configuring as a mixed form of excavatum and carinatum features. Surgical correction of pectus arcuatum always includes one or more horizontal sternal osteotomies, consisting in performing a V-shaped horizontal cutting of the sternum (resection prism) by means of an oscillating power saw. The angle between the saw and the sternal body in the V-shaped cut is determined according to the peculiarity of the specific sternal arch. The choice of the right angle, decided by the surgeon on the basis of her/his experience, is crucial for a successful intervention. The availability of a patient-specific surgical guide conveying the correct cutting angles can considerably improve the chances of success and, at the same time, reduce the intervention time. The present paper aims to propose a new CAD-based approach to design and produce custom-made surgical guides, manufactured by using additive manufacturing techniques, to assist the sternal osteotomy. Starting from CT images, the procedure allows to determine correct resection prism and to shape the surgical guide accordingly taking into account additive manufacturing capabilities. Virtually tested against three case studies the procedure demonstrated its effectiveness.

Keywords: Biomedical devices | CAD | Design for additive manufacturing | Medical imaging

[62] Volpe Y., Furferi R., Governi L., Uccheddu F., Carfagni M., Mussa F., Scagnet M., Genitori L., Surgery of complex craniofacial defects: A single-step AM-based methodology, Computer Methods and Programs in Biomedicine, 165, 225-233, (2018). Abstract
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Background and objective: The purpose of the present paper is to pave the road to the systematic optimization of complex craniofacial surgical intervention and to validate a design methodology for the virtual surgery and the fabrication of cranium vault custom plates. Recent advances in the field of medical imaging, image processing and additive manufacturing (AM) have led to new insights in several medical applications. The engineered combination of medical actions and 3D processing steps, foster the optimization of the intervention in terms of operative time and number of sessions needed. Complex craniofacial surgical intervention, such as for instance severe hypertelorism accompanied by skull holes, traditionally requires a first surgery to correctly “resize” the patient cranium and a second surgical session to implant a customized 3D printed prosthesis. Between the two surgical interventions, medical imaging needs to be carried out to aid the design the skull plate. Instead, this paper proposes a CAD/AM-based one-in-all design methodology allowing the surgeons to perform, in a single surgical intervention, both skull correction and implantation. Methods: A strategy envisaging a virtual/mock surgery on a CAD/AM model of the patient cranium so as to plan the surgery and to design the final shape of the cranium plaque is proposed. The procedure relies on patient imaging, 3D geometry reconstruction of the defective skull, virtual planning and mock surgery to determine the hypothetical anatomic 3D model and, finally, to skull plate design and 3D printing. Results: The methodology has been tested on a complex case study. Results demonstrate the feasibility of the proposed approach and a consistent reduction of time and overall cost of the surgery, not to mention the huge benefits on the patient that is subjected to a single surgical operation. Conclusions: Despite a number of AM-based methodologies have been proposed for designing cranial implants or to correct orbital hypertelorism, to the best of the authors’ knowledge, the present work is the first to simultaneously treat osteotomy and titanium cranium plaque.

Keywords: Additive manufacturing | CAD | Cranium surgery | Image processing

[63] Bartalucci C., Furferi R., Governi L., Volpe Y., A survey of methods for symmetry detection on 3D high point density models in biomedicine, Symmetry, 10(7), (2018). Abstract
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Versatile, cheap and non-invasive 3D acquisition techniques have received attention and interest in the field of biomedicine in recent years as the accuracy of developed devices permits the acquisition of human body shapes in detail. Interest in these technologies derives from the fact that they have the potential to overcome some limitations of invasive techniques (CT, X-rays, etc.) and those based on 2D photographs for the acquisition of 3D geometry. However, the data acquired from the 3D scanner cannot be directly used but need to be processed as they consist of 3D coordinates of the acquired points. Therefore, many researchers have proposed different algorithms which recognise the shape of human body and/or its features when starting from a 3D point cloud. Among all possible human body features to be evaluated, symmetry results the most relevant one. Accordingly, this survey systematically investigates the methods proposed in the literature to recognise 2D symmetry by the symmetry line and bilateral symmetry by the symmetry plane. The paper also analyses qualitative comparisons among the proposed methods to provide a guide for both practitioners and researchers.

Keywords: 3D scan | Digital human model | Symmetry line | Symmetry plane

[64] Uccheddu F., Ghionzoli M., Volpe Y., Servi M., Furferi R., Governi L., Facchini F., Lo Piccolo R., McGreevy K.S., Martin A., Carfagni M., Messineo A., A Novel Objective Approach to the External Measurement of Pectus Excavatum Severity by Means of an Optical Device, Annals of Thoracic Surgery, 106(1), 221-227, (2018). Abstract
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Background: Current approaches to quantifying the severity of pectus excavatum require internal measurements based on cross-sectional imaging. The aim of this study is to exploit a novel index evaluated on the external surface of the chest with a three-dimensional (3D) optical scanner. Methods: Fifty-one children (41 male, 10 female) between 2 and 17 years of age were evaluated with a 3D optical scanner. Pectus excavatum severity was calculated by using an ad hoc instant 3D scanner and defining an automatic procedure to generate an optical 3D correction index (CI3D). For the latter, an ideal threshold was derived from a statistical analysis, and five blind surveys were collected from pediatric specialists on chest wall deformities. The CI3D was then correlated with blind clinical assessments of PE severity. Results: The cutoff thresholds were determined to optimally discriminate between six degrees of severity of PE patients by a correlation analysis. The correlation coefficient obtained by matching the CI3D with the average subjective severity shows that the proposed method outperforms traditional approaches. Conclusions: The optical 3D index has a good match with the average subjective assessment in distinguishing patients with mild to severe PE. This innovative approach offers several advantages over existing indices, as it is repeatable and does not require cross-sectional imaging. The index might be particularly suitable for monitoring the efficacy of nonoperative treatment and, in the future, for designing an optimal personalized usage of therapeutic devices.

[65] Buonamici F., Furferi R., Governi L., Puggelli L., Volpe Y., Tactile reproduction of paintings: The experience of the Department of Industrial Engineering of Florence, IOP Conference Series: Materials Science and Engineering, 364(1), (2018). Abstract
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Within the T-VedO project, financed by Tuscany Region, the Reverse Engineering and Virtual Prototyping Lab team of the Department of Industrial Engineering of Florence (Italy) developed a number of methods for the semiautomatic generation of digital 2.5D models starting from paintings. Once such models are prototyped, they can be used to enhance visually impaired people tactile experience of artworks. Such methods, combined into a systematic procedure, allow to solve most of the typical problems arising when dealing with artistic representation of a painted scene. The present paper presents both an overview of the proposed procedure, including most recent updates, and the results obtained for a selected number of artworks of the Florentine Renaissance.

Keywords: 2.5D models | 3D Reconstruction | CAD

[66] Furferi R., Giorgi R., Governi L., Matteini M., Volpe Y., Preface, IOP Conference Series: Materials Science and Engineering, 364(1), (2018).
[67] Buonamici F., Carfagni M., Furferi R., Governi L., Lapini A., Volpe Y., Reverse engineering modeling methods and tools: a survey, Computer-Aided Design and Applications, 15(3), 443-464, (2018). Abstract
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Reverse Engineering (RE) is a long-term goal of engineering and computer science; it aims at the reconstruction of CAD models from measured data by means of 3D mathematical surfaces and geometrical features representing the geometry of a physical part. In the last two decades, reviews and surveys have occasionally covered this topic, but a systematic dissertation of modeling methods from a mechanical engineering point of view is still missing. The purpose of this paper is to fill this gap; starting from a general description of the overall RE framework (acquisition, segmentation, classification, fitting), both an up-to-date survey and a categorization of available modeling techniques and tools working on 3D data are provided. The main aspects of various strategies are discussed as well, in order to highlight strengths and weaknesses characterizing different approaches. Moreover, an overview of commercial software for RE is presented, considering both dedicated solutions and packages supplied as add-on with ‘traditional’ CAD systems. Finally, possible improvements to be addressed by the research in the RE field are discussed, outlining potential future trends that are still to be investigated.

Keywords: 3D modeling | CAD reconstruction | constrained fitting | Reverse engineering | reverse engineering software

[68] Uccheddu F., Carfagni M., Governi L., Furferi R., Volpe Y., Nocerino E., 3D printing of cardiac structures from medical images: an overview of methods and interactive tools, International Journal on Interactive Design and Manufacturing, 12(2), 597-609, (2018). Abstract
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The percutaneous interventions in the treatment of structural heart diseases represent nowadays a viable option for patients at high risk for surgery. However, unlike during the traditional open heart surgery, the heart structures to be corrected are not directly visualized by the physician during the interventions. The interpretation of the available medical images is often a demanding task and needs specific skills i.e. clinical experience and complex radiological and echocardiographic analysis. The new trend for cardiovascular diagnosis, surgical planning and intervention is, today, mutually connected with most recent developments in the field of 3D acquisition, interactive modelling and rapid prototyping techniques. This is particularly true when dealing with complex heart diseases since 3D-based techniques can really help in providing an accurate planning of the intervention and to support surgical intervention. To help the research community in confronting with this new trend in medical science, the present work provides an overview on most recent approaches and methodologies for creating physical prototypes of patient-specific cardiac structures, with particular reference to most critical phases such as: 3D image acquisition, interactive image segmentation and restoration, interactive 3D model reconstruction, physical prototyping through additive manufacturing. To this purpose, first, recent techniques for image enhancement to highlight anatomical structures of interest are presented together with the current state of the art of interactive image segmentation. Finally, most suitable techniques for prototyping the retrieved 3D model are investigated so as to derive a number of criteria for manufacturing prototypes useful for planning the medical intervention.

Keywords: 3D modelling | Cardiovascular diseases | Heart | Medical imagery | Rapid prototyping | Surgical planning

[69] Buonamici F., Carfagni M., Furferi R., Governi L., Lapini A., Volpe Y., Reverse engineering of mechanical parts: A template-based approach, Journal of Computational Design and Engineering, 5(2), 145-159, (2018). Abstract
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Template-Based reverse engineering approaches represent a relatively poorly explored strategy in the field of CAD reconstruction from polygonal models. Inspired by recent works suggesting the possibility/opportunity of exploiting a parametric description (i.e. CAD template) of the object to be reconstructed in order to retrieve a meaningful digital representation, a novel reverse engineering approach for the reconstruction of CAD models starting from 3D mesh data is proposed. The reconstruction process is performed relying on a CAD template, whose feature tree and geometric constraints are defined according to the a priori information on the physical object. The CAD template is fitted upon the mesh data, optimizing its dimensional parameters and positioning/orientation by means of a particle swarm optimization algorithm. As a result, a parametric CAD model that perfectly fulfils the imposed geometric relations is produced and a feature tree, defining an associative modelling history, is available to the reverse engineer. The proposed implementation exploits a cooperation between a CAD software package (Siemens NX) and a numerical software environment (MATLAB). Five reconstruction tests, covering both synthetic and real-scanned mesh data, are presented and discussed in the manuscript; the results are finally compared with models generated by state of the art reverse engineering software and key aspects to be addressed in future work are hinted at.

Keywords: 3D mesh | CAD reconstruction | CAD template | Constrained fitting | Particle Swarm Optimization | Reverse engineering

[70] Furferi R., Governi L., Uccheddu F., Volpe Y., Computer-aided design tool for GT ventilation system ductworks, Computer-Aided Design and Applications, 15(2), 170-179, (2018). Abstract
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The design of gas turbine ventilation systems (VSs) is a lengthy and tedious process, often requiring weeks to refine a single design concept and by additional time to manufacture it. This is particularly true when dealing with structural design since the typical approach followed by main worldwide manufacturing companies is to outsource finite elements analysis and, often, the 3d modelling phase itself. Moreover, the structural design process is iterative: the modeling and finite elements analysis steps are repeated several times whenever a new VS has to be produced. Accordingly, speeding-up the structural design phase is today a crucial issue for gas turbine sector. Keeping the above objective in mind, the present paper proposes a CAD-based tool, implemented in a commercial 3D CAD software package (SolidWorks), supporting and partly automating the complex structural VS design process. The solution suggested in this work consists of the design and implementation of a SolidWorks add-in, called DuctWorks, developed by using C# programming language. Differently from commercially available solutions, the proposed tool is specifically thought keeping in mind the necessity of performing a final structural assessment, which is of utmost importance given the considerable dimensions and stresses this kind of VS are subject to in the specific field of GT and energy production industry. Tested against a set of case studies, DuctWorks proved to be effective in allowing designers to accelerate the ventilation systems design process with excellent results when compared with the traditional design process.

Keywords: CAD tools | FEA | ventilation system

[71] Carfagni M., Facchini F., Furferi R., Ghionzoli M., Governi L., Messineo A., Servi M., Uccheddu F., Volpe Y., A semi-automatic computer-aided method for personalized Vacuum Bell design, Computer-Aided Design and Applications, 15(2), 247-255, (2018). Abstract
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Pectus Excavatum, one of the most frequent chest wall deformities, is characterized by a depression of the sternum and costal cartilages. Patients with mild deformities are generally treated conservatively by using the so called Vacuum Bell (VB) i.e. a suction cup to be placed on the patient's sternal region. Three different sizes, as well as a model fitted for young women, of VB are available on the market. Unfortunately, the variability of the surface to be treated, the possible asymmetry of the caved-in area and the prolonged use, can make the device uncomfortable and, in some cases, ineffective for the patient. In order to cope with these issues, the present paper proposes a computer-aided method for customized vacuum bell design to be used by non-expert user, e.g. by medical staff. In particular, the present work entails the development of a system comprising: 1) a dedicated software capable of acquiring the 3D chest geometry - by using a low-cost range sensor, i.e. Kinect v2 - and of processing the point cloud so to generate NURBS surfaces of the chest; 2) a procedural CAD modeling of a personalized VB implemented within Siemens NX 11 CAD environment. Using the devised method, the medical staff is required only to use the 3D scanning system for acquiring the patient chest and to sketch, in a CAD-based interface, the boundary of the area to be treated. Once these tasks are performed, the system automatically builds the personalized VB model, ready to be manufactured.

Keywords: design customization | Procedural CAD modeling | reverse engineering | vacuum bell

[72] Bartalucci C., Borchi F., Carfagni M., Furferi R., Governi L., Lapini A., Volpe Y., Curcuruto S., Mazzocchi E., Marsico G., Luzzi S., Bellomini R., Nizzola C.M., Maggi M., Fasanella A., LIFE MONZA: Project description and actions’ updating, Noise Mapping, 5(1), 60-70, (2018). Abstract
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The introduction of Low Emission Zones, urban areas subject to road traffic restrictions in order to ensure compliance with the air pollutants limit values set by the European Directive on ambient air quality (2008/50/EC), is a common and well-established action in the administrative government of cities. The impacts on air quality improvement are widely analysed, whereas the effects and benefits concerning the noise have not been addressed in a comprehensive manner. As a consequence, the definition, the criteria for the analysis and the management methods of a Noise Low Emission Zone are not clearly expressed and shared yet. The LIFE MONZA project (Methodologies fOr Noise low emission Zones introduction And management - LIFE15 ENV/IT/000586) addresses these issues. The first objective of the project, co-funded by the European Commission, is to introduce an easy-replicable method for the identification and the management of the Noise Low Emission Zone, an urban area subject to traffic restrictions, whose impacts and benefits regarding noise issues will be analyzed and tested in the pilot area of the city of Monza, located in Northern Italy. Background conditions, structure, objectives of the project and actions’ progress will be discussed in this article.

Keywords: Bottom-up approach | Environmental noise | Low Emission zones | Low noise paving | Smart noise monitoring system | Top-down approach | Urban planning

[73] Servi M., Volpe Y., Uccheddu F., Furferi R., Governi L., Lazzeri S., A preliminary usability assessment of a 3D printable orthosis design system, Communications in Computer and Information Science, 850, 273-280, (2018). Abstract
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The standard treatment for bones fractures entails the use of a tailor-made plaster cast which has several disadvantages: its weight generally causes discomfort, it cannot be taken off without breaking it, it can cause skin rashes and prevents ventilation of the treated area. Therefore, the application of traditional casts to orthopaedics patients does not represent, to date, the best option. To overcome the above-mentioned drawbacks, many strategies based on reverse engineering and additive manufacturing techniques have been proposed and proved to be a valid alternative for producing custom orthoses. Encouraged by the aforementioned results, the authors have developed a low-cost system (called Oplà), specifically dedicated to the hand-wrist-arm district of paediatric patients and capable of creating a 3D CAD model of the orthosis ready to be printed by using additive manufacturing techniques. Such a system comprises a 3D scanner, a control software and a semi-automatic CAD procedure to easily model the orthopaedic device on each patient, without the need of CAD modelling professionals. To evaluate if Oplà can be effectively used by the medical staff to design patient specific 3D printable orthoses in the clinical practice, a preliminary usability assessment has been performed. Five professional nurses from the Meyer Children’s Hospital of Florence (Italy) have been selected and trained in the use of the system. Subsequently, each of them has been asked to perform the whole process for the same patient. Effectiveness, efficiency and satisfaction have been measured in accordance to ISO 9241-11. Results proved that the Oplà system is characterized by a good usability allowing the user to easily and intuitively perform all the tasks in a reasonable time.

Keywords: CAD | Cast modelling | Reverse engineering | Usability

[74] Buonamici F., Carfagni M., Furferi R., Governi L., Saccardi M., Volpe Y., Optimizing fabrication outcome in low-cost FDM machines. Part 2 - tests, Manufacturing Technology, 18(4), 552-558, (2018). Abstract
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Several models of FDM machines, characterized by different architecture and hardware components, have flooded the market in the last 5 years. As a result, given the high sensitivity of FDM to the specific machine characteristics, the search for optimal printing parameters is a renown problem. This two-parts paper proposes an easy-to-follow and low-cost procedure for the characterization of any given FDM machine. The method allows the evaluation of the effects of a wide selection of FDM process parameters on the quality of 3D printed parts. The first part focused on the definition of a series of metrics to be measured on a series of test prints to evaluate the quality of the produced parts. The evaluation of seven quality parameters on a single print is made possible thanks to: i) a specifically designed specimen that is made available to the user and ii) a rigorous and repeatable measurement procedure, which are both discussed in the first part of the paper. This second part presents the characterization procedure, the statistical tools used in the experimentation (DOE tools and principles are adopted throughout the experimentation) and provides guidelines to be used for the characterization of any FDM machine. The whole procedure is tested on a desktop FDM machine to demonstrate obtainable results, proving the efficacy of the proposed methodology and highlight strengths and drawbacks of the approach.

Keywords: 3D printing | Additive manufacturing (AM) | Design of experiments (DOE) | Fused deposition modeling (FDM) | Process optimization

[75] Secciani N., Bianchi M., Meschini A., Ridolfi A., Volpe Y., Governi L., Allotta B., Assistive hand exoskeletons: The prototypes evolution at the university of florence, Mechanisms and Machine Science, 68, 307-315, (2018). Abstract
X

Robotic assistance to hand-impaired people represents an as difficult as important challenge. In this context, the research work of the Department of Industrial Engineering of the University of Florence (UNIFI) led to a tailor-made wearable device for rehabilitative and assistive purposes. In this paper, the synthesis of the development process, sequentially ordered, is given.

[76] Buonamici F., Carfagni M., Furferi R., Governi L., Saccardi M., Volpe Y., Optimizing fabrication outcome in low-cost FDM machines. Part 1-Metrics, Manufacturing Technology, 18(3), 372-378, (2018). Abstract
X

Several models of FDM machines, characterized by different architecture and hardware components, have flooded the market in the last 5 years. As a result, given the high sensitivity of FDM to the specific machine characteristics, the search for optimal printing parameters is a renown problem. This two-parts paper proposes an easy-to-follow and low-cost procedure for the characterization of any given FDM machine. The method allows the evaluation of the effects of a wide selection of FDM process parameters on the quality of 3D printed parts. The first part focuses on the definition of a series of metrics to be measured on a series of test prints to evaluate the quality of the produced parts. Specifically, several effects are considered: dimensional accuracy, small details, overhang surfaces, ability of printing small holes/thin extrusions and overall quality of the prints. The evaluation of seven quality parameters on a single print is made possible thanks to: i) a specifically designed specimen that is made available to the user and ii) a rigorous and repeatable measurement procedure, which are both discussed in the first part of the paper. The second part presents the characterization procedure, the statistical tools used in the experimentation and provides guidelines to be used for the characterization of any FDM machine. The whole procedure is tested on a desktop FDM machine to demonstrate obtainable results.

Keywords: 3D Printing | Additive Manufacturing (AM) | Design of Experiments (DOE) | Fused Deposition Modeling (FDM) | Process Optimization

[77] Buonamici F., Furferi R., Governi L., Lazzeri S., McGreevy K.S., Servi M., Talanti E., Uccheddu F., Volpe Y., A CAD-based procedure for designing 3D printable arm-wrist-hand cast, Computer-Aided Design and Applications, 16(1), 25-34, (2018). Abstract
X

Wrist injuries are one of the most common fractures, specifically around 25% of fractures among the pediatric population and up to 18% in the elderly age group are distal radius fractures. To date, the standard treatment entails the use of a tailor-made plaster of Paris cast. Although it is a simple and reliable treatment, it presents several disadvantages: its weight generally causes discomfort, it cannot be taken off without breaking it, it can cause skin rashes and prevents ventilation of the treated area. To overcome the limitations of the above mentioned treatment, 3D printed orthopaedic casts based on reverse engineering (RE) and additive manufacturing (AM) techniques have been proposed in literature. Despite these solutions prove to be a valid alternative to the standard treatment, the clinical use of AM-based devices is not trivial due to the need of expert CAD modelers to design the 3D model of the orthosis starting from the patient’s anatomy 3D acquisition. In this work, the authors identify a systematic procedure to create an orthosis model, compliant with medical guidelines, using common CAD tools. The systematic procedure, even still manually performed, envisages a set of tasks, grouped into five main blocks, that will be easy to be automatized in the future, thus eliminating the necessity of designing expertise to model the orthosis. The proposed procedure allows to design a device composed of two halves, to ease the application, locked through a zip tie-based mechanism. A preliminary ventilation pattern is proposed and tested with a FEM analysis to ensure structural resistance. The procedure has been tested on six case studies: all the orthoses models were correctly generated without major complications and positive user feedbacks were generally obtained throughout the tests.

Keywords: Cad | Cast modeling | Orthosis modelling | Personalized medicine | Reverse engineering

[78] Buonamici F., Furferi R., Genitori L., Governi L., Marzola A., Mussa F., Volpe Y., Reverse engineering techniques for virtual reconstruction of defective skulls: An overview of existing approaches, Computer-Aided Design and Applications, 16(1), 103-112, (2018). Abstract
X

The surgical process adopted to repair cranial defects using an implant, typically called Cranioplasty, has seen an abrupt increase in recent years due to the introduction of Reverse Engineering (RE) and Additive Manufacturing (AM) techniques. By adopting these techniques, CT/MRI data can be used to reconstruct, in a pre-operative stage, the 3D anatomy of the defective skull in order to design a patient-specific digital model of the prosthesis. The so-designed cranial plate can be then fabricated via AM, in a suitable metal alloy, and implanted. This allows for a perfect fit of the implant during the actual surgery, reducing the risks for the patient and increasing the efficacy of the treatment. This paper reviews existing approaches for the virtual reconstruction of defective skulls, and a basic classification, proposing four different classes of strategies (Mirroring, Surface Interpolation, Template-Based and Slice-based techniques) is provided. The findings of the study suggest that the reconstruction of skull defects is still an open problem, due to the complexities imposed by surface that needs to be retrieved (i.e. the human anatomy). All the presented approaches share weaknesses and limits, which are discussed in the article. Finally, possible directions to improve the existing techniques are briefly presented.

Keywords: Biomedical engineering | Cranioplasty | Reverse engineering | Skull reconstruction

[79] Furferi R., Governi L., Volpe Y., Puggelli L., Carfagni M., Original strategy for avoiding over-smoothing in SFS problem resolution, International Journal of Computational Vision and Robotics, 8(1), 58-73, (2018). Abstract
X

With the aim of retrieving 3D surfaces starting from single shaded images, i.e. for solving the widely known shape from shading problem, an important class of methods is based on minimisation techniques where the expected surface to be retrieved is supposed to be coincident with the one that minimise a properly developed functional, consisting of several contributions. Despite several different contributes that can be explored to define a functional, the so called 'smoothness constraint' is a cornerstone since it is the most relevant contribute to guide the convergence of the minimisation process towards a more accurate solution. Unfortunately, in case input shaded image is characterised by areas where actual brightness changes rapidly, such a constraint introduces an undesired over-smoothing effect for the retrieved surface. The present work proposes an original strategy for avoiding such a typical over-smoothing effect, with regard to the image regions in which this is particularly undesired such as, for instance, zones where surface details are to be preserved in the reconstruction. The proposed strategy is tested against a set of case studies and compared with other traditional SFS-based methods to prove its effectiveness.

Keywords: 3D model | Minimisation | SFS | shape from shading | Smoothing | Smoothness constraint | variational approach

[80] Carfagni M., Furferi R., Governi L., Volpe Y., 3D geometry reconstruction from orthographic views: An improved method exploiting shading information, Computers in Industry, 92-93, 137-151, (2017). Abstract
X

The demand of new tools devoted to integrate aesthetic design into classic parametric CAD suites has undergone a raising interest from the user community. Industrial tools for reconstructing the 3D geometry of an object starting from 2D representations and for surfacing wireframe models according to designers intent, assumed a high relevance and have experienced a steady evolution. The problem of surfacing wireframe models with consistent closing surface patches is still a hot topic in the computer graphics as well as in the industrial field, as demonstrated by a number of recent works. In this paper, authors propose a procedure for enhancing the surfacing process by using shading information, together with the wireframe model. In particular, this work allows to use shading, represented either in a rendered 3D model or sketched by a designer, for retrieving consistent geometrical information related to the 3D object. The procedure is accompanied by some selected case studies, to highlight its strengths and weaknesses.

Keywords: 3D reconstruction | CAD | Hand-drawn sketches | Surfacing | Wireframe model

[81] Conti R., Meli E., Ridolfi A., Bianchi M., Governi L., Volpe Y., Allotta B., Kinematic synthesis and testing of a new portable hand exoskeleton, Meccanica, 52(11-12), 2873-2897, (2017). Abstract
X

In this research activity, a new methodology for the synthesis of hand exoskeleton mechanisms has been developed and validated through real prototypes. The innovative methodology is based on a new parallel mechanism and has been tested by building a robotic assistive device for hand opening disabilities applied to real cases. The studied robotic orthosis is designed to be a low-cost, adaptable and portable hand exoskeletons to assist people with hand opening disabilities in their activities of daily livings. As regards the methodology for the synthesis of hand exoskeleton mechanism, the authors propose to use a motion capture system to acquire the real hand phalanx trajectories and the geometrical characteristics of the patient’s hand, and to use optimization algorithms to properly defines the novel kinematic mechanism that better fits the finger trajectories. The preliminary testing phase of the prototype on a single patient is concluded; currently, through the collaboration with an Italian rehabilitation center, a group of patients are testing the proposed HES methodology.

Keywords: Hand exoskeleton | Hand opening disabilities | Kinematic synthesis | Portable and wearable robotics

[82] Carfagni M., Furferi R., Governi L., Servi M., Uccheddu F., Volpe Y., On the Performance of the Intel SR300 Depth Camera: Metrological and Critical Characterization, IEEE Sensors Journal, 17(14), 4508-4519, (2017). Abstract
X

Specifically conceived for applications related to face analytics and tracking, scene segmentation, hand/finger tracking, gaming, augmented reality, and RGB-D cameras are nowadays used even as 3-D scanners. Despite depth cameras' accuracy and precision are not comparable with professional 3-D scanners, they still constitute a promising device for reverse engineering (RE) applications in the close range, due to their low cost. This is particularly true for more recent devices, such as, for instance, the RealSense SR300, which promises to be among the best performing close range depth cameras in the market. Given the potentiality of this new device, and since to date a deep investigation on its performances has not been assessed in scientific literature, the main aim of this paper is to characterize and to provide metrological considerations on the Intel RealSense SR300 depth sensor when this is used as a 3-D scanner. To this end, the device sensor performances are first assessed by applying the existing normative guidelines (i.e. the one published by the Association of German Engineers - Verein Deutscher Ingenieure - VDI/VDE 2634) both to a set of raw captured depth data and to a set acquired with optimized setting of the camera. Then, further assessment of the device performances is carried out by applying some strategies proposed in the literature using optimized sensor setting, to reproduce "real life" conditions for the use as a 3-D scanner. Finally, the performance of the device is critically compared against the performance of latest short-range sensors, thus providing a useful guide, for researchers and practitioners, in an informed choice of the optimal device for their own RE application.

Keywords: depth camera | device characterization | SR300 | structured light | temporal multiplexing | VDI/VDE normative

[83] Puggelli L., Volpe Y., Giurgola S., Analysis of deformations induced by manufacturing processes of fine porcelain whiteware, Lecture Notes in Mechanical Engineering, 0, 1063-1072, (2017). Abstract
X

During sintering, porcelain changes its phase composition as well as its physical and mechanical properties. The most evident effect of these transformations is a significant change of shape, which is a combination of shrinkage and pyroplastic deformations, caused by softening. Both of these phenomena are induced by temperature, which is on its turn influenced by several variable factors that are difficult to predict. Especially for products manufactured in large scale, the resulting shape of artefacts may significantly vary even among the same batch. Consequently, for companies demanding high quality standard, this variability entails a high number of rejected products. For this reason, the present work aims at investigating the amount of variation introduced by firing process for an actual industrial product, independently from other (more or less) known variation sources such as the ones related to materials and forming processes. This could help process engineers to focus their attention when trying to improve the quality of final products.

Keywords: Geometric characterization | Porcelain manufacturing | Reverse Engineering | Scattering analysis

[84] Buonamici F., Furferi R., Governi L., Volpe Y., Designing the architecture of a preliminary system for assisting tactile exploration of bas-reliefs, Journal of Design Research, 15(2), 110-127, (2017). Abstract
X

The participation of blind people (BP) in cultural life can be improved by enhancing methodologies and tools for facilitating the 3D reproduction of artworks and, at the same time, to facilitate their exploration. The creation of integrated systems including not only tactile media such as, for instance, sculptures or bas-reliefs but even a set of tools capable of providing the users with an experience cognitively comparable to the one originally envisioned by the artist, may undoubtedly enhance artworks exploration. The present work aims to design a conceptual system to aid BP in the tactile exploration of bas-reliefs. This conceptual system comprises both a hand-tracking system and an audio device, together with a number of methodologies, algorithms and information related to physical design. The designed layout, preliminarily tested to understand its potential and limits, proved to be a promising first attempt in enhancing the BP exploration experience.

Keywords: 3D reconstruction | Blind people | Hand-tracking system | Tactile bas-relief | Tactile exploration

[85] Carfagni M., Furferi R., Governi L., Servi M., Uccheddu F., Volpe Y., Mcgreevy K., Fast and Low Cost Acquisition and Reconstruction System for Human Hand-wrist-arm Anatomy, Procedia Manufacturing, 11, 1600-1608, (2017). Abstract
X

3D body scanners are nowadays used in a range of applications spanning from health, fashion and fitness to reverse engineering applications for robotics and computer vision. Nowadays very good performances are achievable when using commercial 3D body scanners; however, focusing on relative complex shape of some body details, the results still lack precision and acceptable accuracy. Such critical issue remains unsolved also when dealing with the instantaneous acquisition of the hand-wrist-arm (HWA) anatomy. In this paper, we present a new approach that leverages the emerging 3D depth cameras technologies to design a compact low cost 3D dedicated HWA scanner system capable of delivering almost instantaneous full 3D measurement.

Keywords: 3D body scanner | 3D surface | calibration | depth sensors | hand-wrist-arm anatomy

[86] Furferi R., Ganugi L., Giurgola S., Governi L., Puggelli L., Volpe Y., Enhancing Porcelain Whiteware Quality Assessment by Means of Reverse Engineering-based Procedures, Procedia Manufacturing, 11, 1659-1666, (2017). Abstract
X

During manufacturing, porcelain whiteware changes its shape due to the sintering process. For this reason, leader companies in the field of ceramics apply strict controls on final products in order to reach high quality standards. Typically, three quality parameters are considered: drop of the bottom, bending of the rim and roundness. To date, the assessment of such parameters is still based on visual inspections and manual measurements. In the present paper, authors propose a new quality assessment procedure based on reverse engineering (RE), able to measure the most relevant quality parameters in an effective, reliable and repeatable way.

Keywords: 3D model | 3D reconstruction | 3D scanning | measurement | porcelain | porcelain tableware | quality control | quality parameters | reverse engineering | whiteware

[87] Silvaggio R., Curcuruto S., Bellomini R., Luzzi S., Borchi F., Carfagni M., Volpe Y., Arcangeli G., Nizzola C., Introduction and management of noise low emission zones: Life monza project, 24th International Congress on Sound and Vibration, ICSV 2017, (2017). Abstract
X

The introduction of Low Emission Zones, urban areas subject to road traffic restrictions in order to ensure compliance with the air pollutants limit values, set by the European Directive on ambient air quality (2008/50/EC), is a common and well-established action in the administrative government of cities. The impacts on air quality improvement are widely analyzed, whereas the effects and benefits concerning the noise have not been addressed in a comprehensive manner. The definition, the criteria for analysis and the management methods of a Noise Low Emission Zone are not yet clearly expressed and shared. LIFE MONZA project (Methodologies fOr Noise low emission Zones introduction And management - LIFE15 ENV/IT/000586) addresses these issues. The first objective of the project, co-funded by the European Commission, is to introduce an easy-replicable method for the identification and the management of the Noise Low Emission Zone, an urban area subject to traffic restrictions, whose impacts and benefits regarding noise issues will be analyzed and tested in the pilot area of the city of Monza, located in Northern Italy. Further objectives include the monitoring and the analysis of the effects, due to the introduction of the Noise Low Emission Zone, on air quality improvement and on the wellbeing conditions of the inhabitants of a selected pilot area, the identification of the type of interventions that can induce beneficial and synergistic effects, such as those relating to the planning of traffic flows and the adoption of low-noise pavements, and the active involvement of the population in the definition of a more sustainable lifestyle. Background conditions, structure and objectives of the project will be discussed in this paper.

Keywords: Environmental noise | Low Emission Zones | Sound urban planning

[88] Buonamici F., Carfagni M., Volpe Y., Recent strategies for 3D reconstruction using reverse engineering: A bird’s eye view, Lecture Notes in Mechanical Engineering, 0, 841-850, (2017). Abstract
X

This paper presents a brief review of recent methods and tools available to designers to perform reverse engineering of CAD models starting from 3D scanned data (mesh/points). Initially, the basic RE framework, shared by the vast majority of techniques, is sketched out. Two main RE strategies are subsequently identified and discussed: automatic approaches and user-guided ones.

Keywords: CAD reconstruction | Constrained Fitting | Reverse Engineering

[89] Furferi R., Governi L., Uccheddu F., Volpe Y., A RGB-D based instant body-scanning solution for compact box installation, Lecture Notes in Mechanical Engineering, 0, 819-828, (2017). Abstract
X

Body scanning presents unique value in delivering the first digital asset of a human body thus resulting a fundamental device for a range of applications dealing with health, fashion and fitness. Despite several body scanners are in the market, recently depth cameras such as Microsoft Kinect® have attracted the 3D community; compared with conventional 3D scanning systems, these sensors are able to capture depth and RGB data at video rate and even if quality and depth resolution are not optimal for this kind of applications, the major benefit comes from the overall acquisition speed and from the IR pattern that allows poor lighting conditions optimal acquisition. When dealing with non-rigid bodies, unfortunately, the use of a single depth camera may lead to inconsistent results mainly caused by wrong surfaces registration. With the aim of improving existing systems based on low-resolution depth cameras, the present paper describes a novel scanning system for capturing 3D full human body models by using multiple Kinect® devices in a compact setup. The system consists of an instantaneous scanning system using eight depth cameras, appropriately arranged in a compact wireframe. To validate the effectiveness of the proposed architecture, a comparison of the obtained 3D body model with the one obtained using a professional Konica Minolta Range Seven 3D scanner is also presented and possible drawbacks are hinted at.

Keywords: 3D modelling | Body scanning | Custom Avatar | Depth Camera | Model Fitting

[90] Furferi R., Governi L., Volpe Y., Color matching of fabric blends: Hybrid Kubelka-Munk + artificial neural network based method, Journal of Electronic Imaging, 25(6), (2016). Abstract
X

Color matching of fabric blends is a key issue for the textile industry, mainly due to the rising need to create high-quality products for the fashion market. The process of mixing together differently colored fibers to match a desired color is usually performed by using some historical recipes, skillfully managed by company colorists. More often than desired, the first attempt in creating a blend is not satisfactory, thus requiring the experts to spend efforts in changing the recipe with a trial-and-error process. To confront this issue, a number of computer-based methods have been proposed in the last decades, roughly classified into theoretical and artificial neural network (ANN)-based approaches. Inspired by the above literature, the present paper provides a method for accurate estimation of spectrophotometric response of a textile blend composed of differently colored fibers made of different materials. In particular, the performance of the Kubelka-Munk (K-M) theory is enhanced by introducing an artificial intelligence approach to determine a more consistent value of the nonlinear function relationship between the blend and its components. Therefore, a hybrid K-M+ANN-based method capable of modeling the color mixing mechanism is devised to predict the reflectance values of a blend.

Keywords: computer-based color assessment | fabric blend | Kubelka-Munk theory | neural networks | spectrophotometer

[91] Furferi R., Governi L., Volpe Y., Carfagni M., Carded tow real-time color assessment: A spectral camera-based system, Sensors (Switzerland), 16(9), (2016). Abstract
X

One of the most important parameters to be controlled during the production of textile yarns obtained by mixing pre-colored fibers, is the color correspondence between the manufactured yarn and a given reference, usually provided by a designer or a customer. Obtaining yarns from raw pre-colored fibers is a complex manufacturing process entailing a number of steps such as laboratory sampling, color recipe corrections, blowing, carding and spinning. Carding process is the one devoted to transform a “fuzzy mass” of tufted fibers into a regular mass of untwisted fibers, named “tow”. During this process, unfortunately, the correspondence between the color of the tow and the target one cannot be assured, thus leading to yarns whose color differs from the one used for reference. To solve this issue, the main aim of this work is to provide a system able to perform a spectral camera-based real-time measurement of a carded tow, to assess its color correspondence with a reference carded fabric and, at the same time, to monitor the overall quality of the tow during the carding process. Tested against a number of differently colored carded fabrics, the proposed system proved its effectiveness in reliably assessing color correspondence in real-time.

Keywords: Carding process | Color assessment | Spectral camera sensor | Spectrophotometry

[92] Buonamici F., Carfagni M., Furferi R., Governi L., Volpe Y., Are we ready to build a system for assisting blind people in tactile exploration of bas-reliefs?, Sensors (Switzerland), 16(9), (2016). Abstract
X

Nowadays, the creation of methodologies and tools for facilitating the 3D reproduction of artworks and, contextually, to make their exploration possible and more meaningful for blind users is becoming increasingly relevant in society. Accordingly, the creation of integrated systems including both tactile media (e.g., bas-reliefs) and interfaces capable of providing the users with an experience cognitively comparable to the one originally envisioned by the artist, may be considered the next step for enhancing artworks exploration. In light of this, the present work provides a description of a first-attempt system designed to aid blind people (BP) in the tactile exploration of bas-reliefs. In detail, consistent hardware layout, comprising a hand-tracking system based on Kinect® sensor and an audio device, together with a number of methodologies, algorithms and information related to physical design are proposed. Moreover, according to experimental test on the developed system related to the device position, some design alternatives are suggested so as to discuss pros and cons.

Keywords: 3D reconstruction | Blind people | Hand-tracking system | Kinect sensor

[93] Furferi R., Carfagni M., Volpe Y., Governi L., Nanomaterials-based heating devices for cultural heritage application: A patent survey, Micro and Nanosystems, 8(1), 3-12, (2016). Abstract
X

Conservation practices are aimed to implement minimal, targeted and less in-vasive treatments. The conservation profession’s challenges and best practices are therefore becoming more global and mobile, especially when dealing with treatments involving temperature (e.g. painting conservation). The near future of heating devices in art conservation will be with mobile, versatile, accurate and cost effective “smart” devices. For these reasons, the design and manufacturing of heating mats for applications in the Cultural Heritage field moved from early concepts mainly based on electrically heated mats towards more accurate thermo-electrical mild heating devices, especially based on nanomaterials. Despite great scientific efforts have been spent in the last years to create more efficient devices for conservation, there is still room for practically implementing them and, moreover, for protecting new concepts by patenting them. To help the scientific community in getting an overview on the patent state of the art on this important sector, the present work is aimed to provide a survey of patents related to nanomaterials-based heaters to be adopted for artworks conservation. Starting from early works, the paper explores recent patents by selecting the domains referred to nanotechnology sector that are mainly relevant for the heating devices field.

Keywords: Carbon nanotubes | Heating mates | Nanomaterials | Nanotechnology | Paintings conservation | Patents

[94] Carfagni M., Governi L., Volpe Y., Development of a software platform for collaborative MCAD based shoe design, 2008 IEEE International Technology Management Conference, ICE 2008, (2016). Abstract
X

In this paper a novel approach, enabling rapid time to market and making shoe collaborative design effectively possible, will be presented. The solution suggested in this work consists of two elements: first, the implementation of a SolidWorks add-on called SYS (SYstem Shoe) whose main goal is to provide a widespread CAD software packages with specific features for shoe design; secondarily the development of a web platform, capable to communicate with and control the SYS add-on. This platform provides the unique opportunity of making the entire system (installed on a server PC) available to external users (small factories concurring to the shoe production chain), without the need of a CAD software own installation. The scenario in which the described system is supposed to work consists of a inter-company network with a main node equipped with the web-CAD platform. This main node acts as a server towards the peripheral nodes (clients: shoe assembly and component-making companies).

Keywords: collaborative design | reverse engineering | Shoe design

[95] Carfagni M., Furferi R., Governi L., Puggelli L., Volpe Y., Two simple yet effective strategies for avoiding over-smoothing in SFS problem, Journal of Computer Science, 12(3), 128-140, (2016). Abstract
X

Minimization techniques are widely used for retrieving a 3D surface starting from a single shaded image i.e., for solving the shape from shading problem. Such techniques are based on the assumption that expected surface to be retrieved coincides with the one that minimize a properly developed functional, consisting of several contributions. Among the possible contributes defining the functional, the so called "smoothness constraint" is always used since it guides the convergence of the minimization process towards a more accurate solution. Unfortunately, in areas where actually brightness changes rapidly, it also introduces an undesired over-smoothing effect. The present work proposes two simple yet effective strategies for avoiding the typical over-smoothing effect, with regards to the image regions in which this effect is particularly undesired (e.g., areas where surface details are to be preserved in the reconstruction). Tested against a set of case studies the strategies prove to outperform traditional SFS-based methods.

Keywords: 3D model | Minimization | Shape from shading | Smoothing | Smoothness constraint | Variational approach

[96] Allotta B., Conti R., Governi L., Meli E., Ridolfi A., Volpe Y., Development and experimental testing of a portable hand exoskeleton, IEEE International Conference on Intelligent Robots and Systems, 2015-December, 5339-5344, (2015). Abstract
X

In this paper, the development and the experimental testing phases of an innovative assistive device for hand disabilities are presented. This robotic device is based on an parallel kinematic chain applied to a single phalanx architecture and it is designed to be extremely portable to easily assist people with physical disabilities in their everyday lives. Focusing on patients with hand opening disabilities, the authors have developed a model-based methodology which starting from the motion capture of the patient fingertip trajectories is able to define the mechanism that better fits with such trajectories. The authors have validated the proposed innovative mechanism by developing a portable Hand Exoskeleton System (HES) prototype and performing a suitable preliminary testing campaign. The testing phase of the real prototype on a group of patients is currently ongoing.

Keywords: Exoskeletons | Joints | Kinematics | Mathematical model | Prototypes | Solid modeling | Trajectory

[97] Furferi R., Governi L., Volpe Y., Machine vision-based pilling assessment: A review, Journal of Engineered Fibers and Fabrics, 10(3), 79-93, (2015). Abstract
X

Pilling is an undesired defect of textile fabrics, consisting of a surface characterized by a number of roughly spherical masses made of entangled fibers. Mainly caused by the abrasion of fabric surface occurring during washing and wearing of fabrics, this defect needs to be accurately controlled and measured by companies working in the textile industry. Pilling measurement is traditionally performed using manual procedures involving visual control of fabric surface by human experts. Since the early nineties, great efforts in developing automatic and non-intrusive methods for pilling measurement have been made all around the world with the final aim of overcoming traditional, visual-based and subjective procedures. Machine Vision proved to be among the best options to perform such defect assessment since it provided increasingly performing measurement equipment and tools, serving the purpose of automatic control. In particular, a relevant number of interesting works have been proposed so far, sharing the idea of helping (or even replacing) traditional measurement methods using image processing-based ones. The present work provides a rational and chronological review of the most relevant methods for pilling measurement proposed so far. This work serves the purposes of 1) understanding whether today’s automatic machine vision-based pilling measurement techniques are ready for supplanting traditional pilling measurement and 2) providing textile technology researchers with a bird’s eye view of the main methods studied to confront with this problem.

Keywords: Artificial neural networks | Fabrics | Image processing | Machine vision | Pilling assessment | Review

[98] Buonamici F., Furferi R., Governi L., Volpe Y., Making blind people autonomous in the exploration of tactile models: A feasibility study, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 9176, 82-93, (2015). Abstract
X

Blind people are typically excluded from equal access to the world’s visual culture, thus being often unable to achieve concrete benefits of art education and enjoyment. This is particularly true when dealing with paintings due to their bi-dimensional nature impossible to be explored using the sense of touch. This may be partially overcome by translating paintings into tactile bas-reliefs. However, evidence from recent studies suggests that the mere tactile exploration is often not sufficient to fully understand and enjoy bas-reliefs. The integration of different sensorial stimuli proves to dramatically enrich the haptic exploration. Moreover, granting blind people the possibility of autonomously accessing and enjoying pictorial works of art, is undoubtedly a good strategy to enrich their exploration. Accordingly, the main aim of the present work is to assess the feasibility of a new system consisting of a physical bas-relief, a vision system tracking the blind user’s hands during “exploration” and an audio system providing verbal descriptions. The study, supported by preliminary tests, demonstrates the effectiveness of such an approach capable to transform a frustrating, bewildering and negative experience (i.e. the mere tactile exploration) into one that is liberating, fulfilling, stimulating and fun.

Keywords: Blind people | Cultural heritage | Hand tracking | Human-computer interaction

[99] Furferi R., Governi L., Volpe Y., Methods for predicting spectral response of fibers blends, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 9281, 79-86, (2015). Abstract
X

Textile companies usually manufacture fabrics using a mix of pre-colored fibers according to a traditional recipe based on their own experience. Unfortunately, mainly due to the fibers dyeing process, the colorimetric distance between the obtained fabric and the desired one results unsatisfactory with respect to a colorimetric threshold established by the technicians. In such cases, colorists are required to slightly change the original recipe in order to reduce the colorimetric distance. This trial and error process is time-consuming and requires the work of highly skilled operators. Computer-based color recipe assessment methods have been proposed so far in scientific literature to address this issue. Unlikely, many methods are still far to be reliably predictive when the fabric is composed by a high number of components. Accordingly, the present work proposes two alternative methods based on Kubelka-Munk and subtractive mixing able to perform a reliable prediction of the spectrophotometric response of a fabric obtained by means of any variation of a recipe. The assessment performed on a prototypal implementation of the two methods demonstrates that they are suitable for reliable prediction of fabric blends spectral response.

Keywords: Computer-based color assessment | Fabric blend | Kubelka-Munk theory | Spectro-photometer

[100] Volpe Y., Governi L., Furferi R., Computer-aided design of new service doors for recreational vehicles, International Journal of Mechanics, 9, 26-35, (2015). Abstract
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Recreational vehicles (camper, vans and motorhomes) are equipped with service doors to access to specific areas such as water tank or luggage zone. As the state-of-the-art technology stands at present, two different typologies of service doors are manufactured: doors with plastic frames, obtained by injection molding, and doors with aluminum frames realized by extruded bars. Plastic frame-based doors are characterized by concealed hinges (i.e. hinges integrated in the frame), therefore resulting aesthetically pleasant to the final user. Unfortunately, they are basically produced in standard dimensions due to the complexity and costs of injection molding process; as a consequence the number of available measures in the market is really limited. Quite the reverse, aluminum frame-based doors can be produced in customizable formats by adjusting the bars length. The main drawbacks of this second typology of doors are that the cutting and bending machines, used to produce them, need to be periodically tuned in order to take into account possible environmental thermal variations and, moreover, in order to achieve 180° opening, the hinges are required to stick out the wall. Moving from these considerations, this work proposes a CAD/CAE-based design of an innovative service door based on a modular design where frames consist of extruded plastic bars, cut in required length, which are capable to comprise concealed hinges. Accordingly, the new door designed in the present work brings together the advantages offered by the standard solutions pushing forward the RV door technological state of the art.

Keywords: CAD | CAE | Service doors | Slam test

[101] Volpe Y., Governi L., Furferi R., A computational model for early assessment of padded furniture comfort performance, Human Factors and Ergonomics In Manufacturing, 25(1), 90-105, (2015). Abstract
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Seating comfort has always been a primary issue in the design of padded furniture pieces. This paper proposes a computational model-basedmethodology to assist the designer willing to take comfort into account as a primary requirement for padded furniture design. The methodology is based on a virtual mannequin, which can be tailored to reproduce the average target user, and the complete assembly of the main elements composing a typical armchair. Since contact pressure distribution is recognized to be strictly related to seating comfort perception, the contact occurring between these components, during the seating act, was simulated by means of a finite element solver and the resulting contact pressure distribution was computed. Several simulations were carried out with reference to a set of different armchair layout and materials; the obtained results showed a reasonable agreement with the experimental data recorded by means of a capacitive mat. Finally, by using an exemplificative criterion based on comfort-related pressure distribution parameters, the authors demonstrate the possibility of selecting the best-performing configurations prior to building a physical prototype. The proposed approach, tested on a complex seat and a wide range of possiblematerials, can be considered of general applicability since 1) the virtual mannequin, as opposed to what is reported in a number of scientific works, is not requested to closely resemble a single test subject, and 2) the selected seat structure and seat components encompass the most commonly used ones for this kind of product so that a few generally applicable considerations can be drawn.

Keywords: Comfort assessment | Computational model | Padded furniture design | Seat experiments | Seat modeling

[102] Governi L., Furferi R., Volpe Y., Puggelli L., Vanni N., Tactile exploration of paintings: An interactive procedure for the reconstruction of 2.5D models, 2014 22nd Mediterranean Conference on Control and Automation, MED 2014, 14-19, (2014). Abstract
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Cultural heritage is often not accessible to visually impaired and blind people, hardly ever when dealing with two-dimensional artworks like, for instance, paintings. In fact, despite tactile reproductions of 3D works of art such as sculptures or architectural models are quite common, a real barrier between blind people and pictorial artworks still exists, obviously due to their intrinsic 2D format. The translation of paintings into bas-relieves is recognized to be one of the most effective ways for breaking down such a barrier, thus allowing a sensible improvement in blind people's accessibility to this kind of works of art. Moving from these considerations, in this work the authors want to provide a bird's eye view on a new methodology for the semi-automatic generation of tactile 3D models starting from paintings, in particular those characterized by single-point perspective. The proposed method relies on an interactive Computer-based modelling procedure, which is conceived to be simple and effective to use. The procedure, which has been implemented into a prototypal software package, has been effectively used to 'translate' a set of paintings from the Italian Renaissance.

[103] Furferi R., Governi L., Vanni N., Volpe Y., Tactile 3D bas-relief from single-point perspective paintings: A computer based method, Journal of Information and Computational Science, 11(16), 5667-5680, (2014). Abstract
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Visually impaired and blind people are more excluded from equal access to the world's visual culture, thus being often unable to achieve concrete benefits of art education or to experience the life enhancing power of art. Despite the fact that all over the world several initiatives based on the interaction with sculptures and tactile three-dimensional reproductions or architectural aids on scale have been devised, a "sensory barrier" between blind people and pictorial artworks still exists, obviously due to their intrinsic 2D format. Translation of paintings into tactile models in the form of bas-reliefs is recognized to be one of the most effective ways for breaking down such a barrier, thus allowing a tangible improvement of the blind people's accessibility to artworks. In the recent years, computer aided technologies for automatic or semi-automatic translation of paintings into tactile models dramatically have been devised all over the world, thus improving blind people's accessibility to artworks. Inspired by some of these impressive works, this paper describes a user-driven methodology for the semi-automatic generation of tactile 3D models starting from paintings. Particularly devoted to the reconstruction of pictorial artworks characterized by single-point perspective, the proposed method relies on an interactive Computer-based modelling procedure. The method has been tested on two masterpieces of the Italian Renaissance period.

Keywords: 3d computer based modelling | Blind people | Haptic exploration | Single-point perspective | Tactile bas-relief

[104] Furferi R., Carfagni M., Governi L., Volpe Y., Bogani P., Towards automated and objective assessment of fabric pilling, International Journal of Advanced Robotic Systems, 11, (2014). Abstract
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Pilling is a complex property of textile fabrics, representing, for the final user, a non-desired feature to be controlled and measured by companies working in the textile industry. Traditionally, pilling is assessed by visually comparing fabrics with reference to a set of standard images, thus often resulting in inconsistent quality control. A number of methods using machine vision have been proposed all over the world, with almost all sharing the idea that pilling can be assessed by determining the number of pills or the area occupied by the pills on the fabric surface. In the present work a different approach is proposed: instead of determining the number of pills, a machine vision-based procedure is devised with the aim of extracting a number of parameters characterizing the fabric. These are then used to train an artificial neural network to automatically grade the fabrics in terms of pilling. Tested against a set of differently pilled fabrics, the method shows its effectiveness.

Keywords: Computational vision | Image processing | Machine vision system | Neural networks | Pilling | Textile industry

[105] Governi L., Furferi R., Puggelli L., Volpe Y., A practical approach based on shape from shading and fast marching for 3D geometry recovery under oblique illumination, Applied Mechanics and Materials, 472, 503-509, (2014). Abstract
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Design of new industrial objects characterized by high stylistic content often starts from sketches or images of the product to be, subsequently, represented in a 3D digital form by using CAD software. To speed up this phase, a number of methods for automatic or semi-automatic translation of sketches or images into a 3D model have been devised all over the world also for reverse engineering purposes. When the image shading is a crucial information for recovering the final 3D shape, Fast Marching is recognized to be among the best method to date, especially for frontally illuminated scenes. Unfortunately, such a method cannot be directly applied when object illumination in the considered image is oblique. The present work is aimed to propose a simple, but effective, approach for recovering 3D shape of objects starting from single side illuminated scenes i.e. for solving non-eikonal SFS problems. Tested against a set of case studies, the method proved its effectiveness. © (2014) Trans Tech Publications, Switzerland.

Keywords: Digital design | Fast marching | Intelligent manufacturing | Oblique illumination | Shape from shading

[106] Furferi R., Governi L., Volpe Y., Puggelli L., Vanni N., Carfagni M., From 2D to 2.5D i.e. from painting to tactile model, Graphical Models, 76(6), 706-723, (2014). Abstract
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Commonly used to produce the visual effect of full 3D scene on reduced depth supports, bas relief can be successfully employed to help blind people to access inherently bi-dimensional works of art. Despite a number of methods have been proposed dealing with the issue of recovering 3D or 2.5D surfaces from single images, only a few of them explicitly address the recovery problem from paintings and, more specifically, the needs of visually impaired and blind people. The main aim of the present paper is to provide a systematic method for the semi-automatic generation of 2.5D models from paintings. Consequently, a number of ad hoc procedures are used to solve most of the typical problems arising when dealing with artistic representation of a scene. Feedbacks provided by a panel of end-users demonstrated the effectiveness of the method in providing models reproducing, using a tactile language, works of art otherwise completely inaccessible.

Keywords: 2.5D model | Minimization techniques | Shape From Shading | Tactile model

[107] Rocco F., Lapo G., Luca P., Volpe Y., Improved interactive method for reco-vering 2.5D models from single images, Journal of Computer Science, 10(10), 2141-2154, (2014). Abstract
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In the last years the development of interactive Computer-based methods for building virtual and physical 2.5D models from single shaded images faced with an exponential growth. In particular, a wide range of methods based on image processing-based procedures and on Shape From Shading (SFS) can be documented. On the basis of the most favorable techniques devised in literature, the present work describes an improved interactive method capable of retrieving 2.5D models using image shading information. The pro-posed method performs a SFS-based reconstruction where (1) the overall geometry of the expected surface is first recovered and (2) the final 2.5D reconstruction is obtained by minimizing a suitable functional using the rough surface as an initialization function. The method improves previous interactive works by introducing a novel two-step rough surface recovery and a new definition of a functional to be minimized for solving the SFS problem. Tested against a set of case studies the proposed method proves to be effective in providing 2.5D models. © 2014 Science Publications.

Keywords: 2.5D model | Image processing | Interactive reconstruction | Minimization | Shape from shading

[108] Markevicius T., Furferi R., Olsson N., Meyer H., Governi L., Carfagni M., Volpe Y., Hegelbach R., Towards the development of a novel CNTs-based flexible mild heater for art conservation, Nanomaterials and Nanotechnology, 4(1), (2014). Abstract
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Mild heating devices currently available to conservators are still limited in terms of precision, versatility, mobility, accessibility and cost. Moreover, they lack a range of operational features, such as low power requirements, efficient power use, temperature stability and uniform heat distribution. Carbon nanotubebased technologies can provide a wide range of technical solutions for overcoming these limitations, thereby allowing the development of more precise, flexible and portable heating devices. This work describes the design of an innovative carbon nanotube-based intelligent mobile accurate thermo-electrical mild heating device, to be used in the art conservation field. The device consists of three different types of flexible heating mats with different designs (opaque and ultra-thin/woven and breathable/transparent) and different operational and physical properties. The entire heating system is completed by a control unit that controls, monitors and registers the heating and by a power supply unit. First tests performed on a series of prototypes of the designed heaters showed that the device was able to convey uniform heating on different working materials, thus proving to be effective for thermal consolidation. © 2014 The Author(s).

Keywords: Carbon nanotubes | Cultural heritage | Mild heating devices

[109] Volpe Y., Furferi R., Governi L., A computer-based system for dyeing leather patch edges, International Journal of Computer Aided Engineering and Technology, 6(2), 139-158, (2014). Abstract
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The visual appearance of seamless dyed edges of luxury leather goods represents a key issue in terms of quality grading since a high-quality leather has to be characterised by homogeneously coloured and shaped edges with uniform ink thickness. Despite a huge literature produced by scientific and technical community to automate many leather manufacturing processes, since leather patches are often characterised by a free-form shape, any attempt of automating leather edges dyeing produced unsatisfactory and inaccurate results. In order to overcome the drawbacks of the existing approaches, the main objective of the present work is to provide a computer-based system for automatically dyeing leather patches edges. The described system includes: 1) a machine vision (MV) hardware equipment, consisting of both illumination and a high resolution acquisition device, devoted to patches edge detection; 2) a pantograph whose dyeing tool is moved along leather edges; 3) a series of computer-based methods for the automatic extraction of the leather patches outlines. Extensive testing performed using the developed machine demonstrated its effectiveness in delivering fast, automatic and high quality edge finishing in a reliable and repeatable way. © 2014 Inderscience Enterprises Ltd.

Keywords: Leather dyeing | Machine vision | Process automation

[110] Volpe Y., Furferi R., Governi L., Tennirelli G., Computer-based methodologies for semi-automatic 3D model generation from paintings, International Journal of Computer Aided Engineering and Technology, 6(1), 88-112, (2014). Abstract
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Over the last few years, technologies like 3D scanning and rapid prototyping provided an extraordinary boost in improving reproductions of 3D artworks, like sculptures and historical buildings, all over the world. Physical 3D reproduction of subjects represented in paintings, is recognised to be one of the best ways to allow visually impaired people to enjoy such kind of artworks. However, the use of advanced technologies with the aim of realising 3D models starting from paintings has not been satisfactorily investigated yet. Though a number of algorithms coming from computer vision science exist to cope with similar issues, the specific problem of producing a 3D representation which is targeted at blind people tactile exploration has been only marginally investigated. Starting from these considerations, this work presents 1) a quite extensive review of the criteria proposed in literature for producing tactile models suitable for blind people and 2) four alternative computer-based methods for semi-automatic generation of tactile 3D models starting from RGB digital images of paintings. The outcomes of this study contribute new information to the field of visually impaired user-oriented 3D reconstruction and clearly indicate the strategy to be adopted in order to produce a meaningful reproduction of a bi-dimensional piece of artwork. © 2014 Inderscience Enterprises Ltd.

Keywords: 3D computer-based modelling | Blind | Haptic exploration | Visually impaired

[111] Governi L., Carfagni M., Furferi R., Puggelli L., Volpe Y., Digital Bas-Relief Design: A Novel Shape from Shading-Based Method, Computer-Aided Design and Applications, 11(2), 153-164, (2014). Abstract
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Design of products characterized by high stylistic content and organic shapes in the form of bas-relief (e.g. fashion accessories, commemorative plaques and coins) is traditionally performed starting from handmade drawings or photographs that are manually reproduced by highly skilled craftsmen such as sculptors and engravers and finally digitized by means of 3D scanning. Several Computer-based procedures have been devised with the aim of speeding up this process, which is considerably time consuming, subjective and costly; these are mainly based on image processing techniques such as embossing, enhancement, histogram equalization or dynamic range, also implemented in CAD-based commercial software. However, these approaches are characterized by several limitations preventing them from providing a "correct" final geometry. In view of that, the present work describes a novel method for the creation of digital bas-reliefs from a single image using a Shape From Shading (SFS) based approach with interactive initialization. Image processing-based techniques and minimization SFS methods are first used in order to retrieve a rough version of the objective surface; successively, this is used as initialization for the final reconstruction algorithm. Tested on a set of case studies, the method proved to be effective in providing satisfactory digital bas-relief from single images. © 2013 © 2013 CAD Solutions, LLC.

Keywords: digital bas-relief | image processing | shape from shading | shape retrieval

[112] Governi L., Furferi R., Palai M., Volpe Y., Detecting intersection zones in thread-like 3D voxel clouds: a novel algorithm based on neighbourhood tracing, Journal of Information and Computational Science, 10(8), 2187-2197, (2013). Abstract
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3D topological segmentation entails the partition of 3D clouds of connected voxels (e.g. 3D images) into sets of entities, connected by a series of nodes. Especially for thread-like structures (e.g. blood vessels, proteins, piping and voxel-based 3D sketches), nodes detection and, more in particular, identification of entities converging in a node may be considered a crucial issue to correctly interpret the "structure" of the analysed object. The main objective of the present work is to describe an innovative algorithm able to determine the possible intersection zones between groups of voxels composing a thread-like 3D voxel cloud. The devised algorithm is based on a multi-directional ray-tracing procedure applied, for each voxel of the 3D dataset, with reference to a set of directions defined by an appropriate 3D neighbourhood domain. The thread-like structure thicknesses, coming from the ray-trace analysis, are estimated along different directions. Finally, the set of thicknesses is analysed by means of a statistical approach so that voxels, possibly belonging to intersection zones, can be identified. The proposed algorithm demonstrated its effectiveness in a number of test cases. Copyright © 2013 Binary Information Press.

Keywords: 3D topology | Local thickness | Ray-trace analysis | Voxel graphics

[113] Furferi R., Governi L., Volpe Y., Carfagni M., Design and assessment of a machine vision system for automatic vehicle wheel alignment, International Journal of Advanced Robotic Systems, 10, (2013). Abstract
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Wheel alignment, consisting of properly checking the wheel characteristic angles against vehicle manufacturers' specifications, is a crucial task in the automotive field since it prevents irregular tyre wear andaffects vehicle handling and safety. In recent years, systems based on Machine Vision have been widely studied in order to automatically detect wheels' characteristic angles. In order to overcome the limitations of existing methodologies, due to measurement equipment being mounted onto the wheels, the present work deals with design and assessment of a 3D machine vision-based system for the contactless reconstruction of vehicle wheel geometry, with particular reference to characteristic planes. Such planes, properly referred to as a global coordinate system, are used for determining wheel angles. The effectiveness of the proposed method was tested against a set of measurements carried out using a commercial 3D scanner; the absolute average error in measuring toe and camber angles with the machine vision system resulted in full compatibility with the expected accuracy of wheel alignment systems. © 2013 Furferi et al.

Keywords: Machine vision | Stereovision | Wheel alignment

[114] Furferi R., Governi L., Volpe Y., Image processing-based method for glass tiles colour matching, Imaging Science Journal, 61(2), 183-194, (2013). Abstract
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Furniture glass tiles are increasingly used for covering walls and facades or for conferring fashionable aesthetical properties to buildings. Companies that produce furniture glass tiles of a desired colour are devoted to performing a colour comparison between the manufactured glass tiles and the ones desired by a customer, or provided by a catalogue. Still today, such a comparison, known as 'colour matching', is mainly performed by company experts by means of a visual inspection, thus leading to a subjective and qualitative colour assessment. A number of methods for colour matching have been afforded in the literature in several industrial fields such as textile, plastics or food; unfortunately, to the best of author's knowledge, no practical method for glass tiles colour matching has been devised until today. The present work provides an image processing-based method capable of carrying out nonpatterned glass tiles colour matching. The method is devised using an appositely developed hardware so as to extract a series of statistical data from scanned images of 10 mm sized glass tiles and, on the basis of the definition of two novel colour distance formulas, endows with colour matching. The achieved colour matching performance agrees in 91% of tests with expertperformed colour classification. The provided formulas are meant to be of general usage for assessing glass tiles colour matching. © RPS 2013.

Keywords: Colour gaussian | Colour matching | Glass | Image processing | Mahalanobis

[115] Governi L., Furferi R., Puggelli L., Volpe Y., Improving surface reconstruction in shape from shading using easy-to-set boundary conditions, International Journal of Computational Vision and Robotics, 3(3), 225-247, (2013). Abstract
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Minimisation techniques are commonly adopted methodologies for retrieving a 3D surface starting from its shaded representation (image), i.e., for solving the widely known shape from shading (SFS) problem. Unfortunately, depending on the imaged object to be reconstructed, retrieved surfaces often results to be completely different from the expected ones. In recent years, a number of interactive methods have been explored with the aim of improving surface reconstruction; however, since most of these methods require user interaction performed on a tentative reconstructed surface which often is significantly different from the desired one, it is advisable to increase the quality of the surface, to be further processed, as much as possible. Inspired by such techniques, the present work describes a new method for interactive retrieving of shaded object surface. The proposed approach is meant to recover the expected surface by using easy-to-set boundary conditions, so that the human-computer interaction primarily takes place prior to the surface retrieval. The method, tested on a set of case studies, proves to be effective in achieving sufficiently accurate reconstruction of scenes with both front and side illumination. © 2013 Inderscience Enterprises Ltd.

Keywords: Boundary conditions | Computational vision | Human-computer interaction | Minimisation techniques | SFS | Shape from shading

[116] Carfagni M., Furferi R., Governi L., Volpe Y., A vane-motor automatic design procedure, International Journal on Interactive Design and Manufacturing, 7(3), 147-157, (2013). Abstract
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Because of their features, pneumatic motors are often preferred to their electrical counterparts in a number of industrial applications. In spite of their growing diffusion, to the best of authors knowledge, a well-established design procedure is still missing due to the large number of factors (e.g. friction, fluid-dynamic losses, etc.) introducing non idealities in the motor behaviour. Moving from these considerations, this work aims to illustrate the development of a design methodology, implemented in the form of a prototypal software tool, capable of automatically define all the necessary constructive parameters of vane motors on the basis of a required characteristic curve and to considerably speed-up the whole design process. The methodology is based on three main elements: an experimental-mathematical model obtained by means of a DoE approach; a search algorithm meant to identify the constructive solution best matching the design target; a parametric CAD model which is directly driven by the constructive parameters provided by the mathematical model. The presented methodology, applied to the development of a set of pneumatic vane motors, led to the manufacturing of units fulfilling the design target within an error lower than 3 %, thereby demonstrating the effectiveness of the proposed approach. © 2012 Springer-Verlag France.

Keywords: Air motor | Automatic design | Optimization | Parametric modelling

[117] Governi L., Furferi R., Palai M., Volpe Y., 3D geometry reconstruction from orthographic views: A method based on 3D image processing and data fitting, Computers in Industry, 64(9), 1290-1300, (2013). Abstract
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Industrial esthetic designers typically produce hand-drawn sketches in the form of orthographic projections. A subsequent translation from 2D-drawings to 3D-models is usually necessary. This involves a considerably time consuming process, so that some automation is advisable. Common approaches to this "reconstruction problem" start directly from "exact" 2D vector representations or try to vectorize 2D raster images prior to the reconstruction phase. These approaches, however, typically fail to deal with free form geometries like the ones commonly found in esthetic industrial design. This work presents a new methodology suitable for free form geometries, comprising the generation and processing of a 3D voxel image obtained from a hand drawing, the creation of a set of 3D curves fitting the voxel image and the automatic generation of surface patches on the resulting curve network. Several case studies are also presented in order to emphasize and discuss strengths and weaknesses of the proposed method. © 2013 Elsevier B.V. All rights reserved.

Keywords: 3D geometry fitting | 3D reconstruction | Industrial design | Orthographic views | Voxel imaging

[118] Governi L., Furferi R., Volpe Y., A genetic algorithms-based procedure for automatic tolerance allocation integrated in a commercial variation analysis software, Journal of Artificial Intelligence, 5(3), 99-112, (2012). Abstract
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In the functional design process of a mechanical component, the tolerance allocation stage is of primary importance to make the component itself responding to the functional requirements and to cost constraints. Present state-of-the-art approach to tolerance allocation is based on the use of Statistical Tolerance Analysis (STA) software packages which, by means of Monte Carlo simulation, allow forecasting the result of a set of user-selected geometrical and dimensional tolerances. In order to completely automate and optimize this process, this work presents a methodology to allow an automatic tolerance allocation, capable to minimize the manufacturing cost of a single part or assembly. The proposed approach is based on the Monte Carlo method to compute the statistical distribution of the critical to quality characteristics and uses an optimization technique based on Genetic Algorithms. The resulting procedure has been integrated in an off-the-shelf variation analysis software: eM-TolMate (by Siemens AG). Both the description of the optimization algorithm and some practical applications are presented in order to demonstrate the effectiveness of the proposed methodology. © 2012 Asian Network for Scientific Information.

Keywords: Functional design | Genetic algorithms | Monte carlo method | Tolerance allocation

[119] Carfagni M., Furferi R., Governi L., Volpe Y., Tennirelli G., Tactile representation of paintings: An early assessment of possible computer based strategies, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 7616 LNCS, 261-270, (2012). Abstract
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In recent years, a number of works meant to define the criteria for translating two-dimensional art into tactile representation, to be benefit of blind and visually impaired people. Due to technology-related limitations, however, these studies mainly investigated only some kinds of possible representations (e.g. tactile diagrams). This work deals with the analysis of 4 alternative translation strategies, implemented using computer-based tools, to determine the most effective one in delivering blind people a correct perception of pictorial artworks. The outcomes of the study contribute new information to the field of tactile paintings for blind and visually impaired individuals by testing the response of a panel of potential users. © 2012 Springer-Verlag Berlin Heidelberg.

Keywords: blind | Computer-based 3D modeling | haptic exploration | tactile artwork | visually impaired

[120] Furferi R., Governi L., Volpe Y., A novel method for ring spinning performance evaluation based on Computer Aided analysis of yarn geometry, International Journal of Mechanics, 6(4), 212-221, (2012). Abstract
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Yarn hairiness and yarn hand represent key parameters to be strictly assessed and controlled in textile processes since they affect many aspects such as visual appearance of yarns (and consequently of fabrics), handle, thermal insulation, pleasant sensation during touch and smoothness. This is particularly true when fancy yarns, such as jaspè or frisè, are produced using ring spinning: colored natural fibers composing the fancy yarns are required to protrude, to some extent, from the yarn core, usually composed by synthetic material, so as to impart the desired properties in terms of smoothness and luster. With the aim of realizing highest performing fancy yarns, a novel ring spinning system, equipped with a double drafting unit, has been realized by Università di Firenze thanks to the contribute of Tuscany Region (Italy). Once the fancy yarns are obtained, the performance of this innovative ring spinning is evaluated by means of a Computer Aided analysis of yarn geometry able to provide a novel measurement of yarn hairiness and to quantitatively define a yarn hand-related parameter. A Machine Vision system has been devised in order to acquire yarn geometry so that an accurate analysis can be carried out. Such computer aided-based analysis allows to determine two parameters used for determining hairiness and hand: the "equivalent yarn hairiness" and the "yarn hand index". Such parameters are evaluated for yarns obtained using both the innovative and a conventional ring spinning machine so that the yarns quality can be effectively compared. Based on the obtained results that the proposed method proved to be suitable and effective for evaluating yarn hairiness within an average error of about 5.40% with respect to the Uster tester. Furthermore, a good correlation (93%) between objective and subjective assessment of yarn hand was reached.

Keywords: Computer Aided analysis | Image processing | Yarn geometry | Yarn hairiness | Yarn hand

[121] Furferi R., Governi L., Volpe Y., Modelling and simulation of an innovative fabric coating process using artificial neural networks, Textile Research Journal, 82(12), 1282-1294, (2012). Abstract
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A polyurethane-based fabric coating process requires a series of parameters to be set in order to meet the desired quality of the final product. Usually, the optimal setting of such parameters is performed by means of experimental tests, based on the experience of trained operators. The lack of understanding of the interaction between the coating process parameters and the final quality properties of the coated fabric encourages the development of predictive models. The main aim of the present work is to provide a predictive model of a particular coating process for forecasting the final characteristics of a coated fabric, based on the process parameters. The devised model, based on artificial neural networks, is trained and validated using a wide experimental database created with reference to an innovative coating process. Once simulated with new process parameters, the model proves to be capable of determining the best possible process parameter values to obtain the preferred coated fabric properties. By employing the developed model, a series of charts are also built that can be used to provide technicians with a practical tool for effectively selecting the process parameters. © 2012, SAGE Publications. All rights reserved.

Keywords: coatings | systems engineering | testing

[122] Furferi R., Governi L., Palai M., Volpe Y., The reconstruction problem: Integrating different approaches into a systematic procedure for pseudo wireframe retrieval, Journal for Geometry and Graphics, 15(1), 79-91, (2011). Abstract
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Nowadays three-dimensional Computer Aided modeling is of out-standing importance in the mechanical design process since it impacts on several issues like visualization, simulation, machining, etc. Anyway, multi orthographic view engineering drawings have been widely used up to latest decade and still are, so they play an essential role in traditional engineering. The conversion from 2D drawings to 3D CAD models is still a key task in a wide range of applications. In order to cope with this issue a number of works have been proposed in the last decades, providing a series of methodologies for solving the reconstruction prob-lem. On the basis of such methodologies the main aim of the present paper is to suggest a comprehensive, orderly, unambiguous and automatic procedure meant to help researchers and practitioners who want to deal with the reconstruction problem. The procedure, by using an appropriate formal mathematic language, systematize and integrates some of the methods proposed so far. © 2011 Heldermann Verlag.

Keywords: 3D reconstruction | Computational geometry | Computer aided design | Engineering drawings | Or-thographic projections | Pseudo-wireframe

[123] Furferi R., Governi L., Palai M., Volpe Y., Artificial vision based inspection of marbled fabric, Applications of Mathematics and Computer Engineering - American Conference on Applied Mathematics, AMERICAN-MATH'11, 5th WSEAS International Conference on Computer Engineering and Applications, CEA'11, 93-98, (2011). Abstract
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Marbling effect on fabrics is a relevant aesthetic feature, increasing its diffusion specially in the field of textiles for technical applications. The fabric aesthetic anisotropy, characterizing the marbling effect, has a strong impact on the perceived quality: a high-quality marbled fabric to be used in automotive textiles, for instance, is characterized by a tiny quantity of veins and spotted areas. A large amount of "veins" and/or discolored areas may induce a customer to consider the fabric as "defected". In common practice, the identification of whether the fabric is defective or not is performed by human experts by means of visual inspection. As a consequence, fabric inspection is performed in a qualitative and unreliable way; thereby the definition of a method for the automatic and objective inspection is advisable. On the basis of the state of the art, the present work aims to describe a computer-based approach for the automated inspection of marbling effect on fabrics, resulting in the classification of fabrics into three quality classes. The devised apparatus is composed by a machine vision system provided with an image processing-based software. The processing software is able to determine the anisotropy of a fabric using edge segmentation and image entropy and defining a "fabric entropy curve" The proposed method proves to be able to classify the fabrics into the correct quality class in 90% of the cases, with respect to the selection criteria provided by human operators.

Keywords: Artificial vision | Edge detection | Fabric inspection | Image entropy | Marbling effect

[124] Furferi R., Governi L., Palai M., Volpe Y., From unordered point cloud to weighted B-spline - A novel PCA-based method, Applications of Mathematics and Computer Engineering - American Conference on Applied Mathematics, AMERICAN-MATH'11, 5th WSEAS International Conference on Computer Engineering and Applications, CEA'11, 146-151, (2011). Abstract
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Digital applications such as CG, CAD and GIS are based on vectorial data since all the information about shape, size, topology etc. are provided in such kind of data representation rather than raster one. Turning raster images into vector ones is a key issue which has been addressed by a number of authors but still far to be exhaustively worked out. Especially in the case of 2D images representing technical drawings, fitting analytical curves to point clouds (pixel sets) is a critical matter. The present paper provides a novel approach to fit unordered point cloud data. Such an approach integrates a PCA-based method, for detecting the main local directions of the point cloud and to order the points, with and a weighted approximation of a B-spline curve to the original data, based on pixel gray levels. The methodology, tested against alternative techniques based on Least Square (LS) B-spline approximation and on image thinning, proved to be effective in preserving the original shape according to human perception.

Keywords: Curve reconstruction | Image processing | PCA | Unorganized points | Weighted least-squares

[125] Carfagni M., Furferi R., Governi L., Palai M., Volpe Y., "3D reconstruction problem": An automated procedure, Applications of Mathematics and Computer Engineering - American Conference on Applied Mathematics, AMERICAN-MATH'11, 5th WSEAS International Conference on Computer Engineering and Applications, CEA'11, 99-104, (2011). Abstract
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3D CAD techniques represent today a crucial tool in almost all the design fields. Nevertheless, due to a number of well known reasons, multi orthographic view drawings are still widely used; accordingly, the conversion of 2D drawings into 3D CAD models (known in the scientific literature as the "reconstruction problem") is still a key issue. During the last decades a number of works, dealing with the reconstruction problem, have been proposed. On the basis of these works, the authors have developed and implemented an automatic procedure that allows the reconstruction of 3D polyhedral models. The reconstruction procedure involves a number of software routines; by means of them, an initial 2D DXF file is processed and a set of 3D solutions, consistent with the initial drawing, is extracted. The obtained 3D models are subsequently output according to the most common 3D exchange formats (e.g. IGES, STEP, Parasolid, etc.). The proposed procedure and its implementation have been developed in order to achieve two main goals: to introduce researchers into the "reconstruction problem" and to create a common basis in order to methodologically compare different procedures dealing with the "reconstruction problem" itself.

Keywords: 3D reconstruction | CAD | Computational geometry | Engineering drawings | Orthographic projections | Pseudo-wireframe

[126] Furferi R., Governi L., Palai M., Volpe Y., Multiple Incident Splines (MISs) algorithm for topological reconstruction of 2D unordered point clouds, International Journal of Mathematics and Computers in Simulation, 5(2), 171-179, (2011). Abstract
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An automatic 3D model retrieval from freehand conceptual sketches is a key target for both commercial software houses and academic research. Unfortunately, most of the approaches are not suitable for properly translating stylistic sketches into 3D models. In order to carry out this 3D model conversion, the first task to be dealt with is to turn raster data (3D or 2D free-form curves) into vectorial ones. Such a task represents a key issue which has been addressed by a number of authors but still far to be exhaustively worked out. To address this challenge, this work presents a new method that allows to fit 2D unordered point cloud data with Multiple Incident Splines (MISs). At the heart of the proposed approach are two main procedures: the first one is based on Euclidean Minimum Spanning Tree (EMST) and Principal Component Analysis (PCA) for detecting the main local directions of the point cloud and to order its points while preserving original topology; the second is meant to fit ordered point clouds with spline curves providing a robust intersection and vertex detection. The proposed methodology, tested on a number of case studies, proves to preserve the original topology more efficiently than alternative techniques supplied by commercial vectorization software packages.

Keywords: Curve reconstruction | Freehand sketches | Image Processing | Styling | Unorganized point cloud

[127] Furferi R., Governi L., Volpe Y., Neural network based classification of car seat fabrics, International Journal of Mathematical Models and Methods in Applied Sciences, 5(3), 696-703, (2011). Abstract
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Car seat fabrics are uniquely fashioned textiles. A number of them is branded by a sponged-like appearance, characterized by spots and slightly discoloured areas. Their surface anisotropy is considered to be a relevant aesthetic feature since it has a strong impact on customer perceived quality. A first-rate car seat fabric requires a "small" quantity of spots and discoloured areas while fabrics characterized either by a large number or by a low number of spots, are considered to be of lower quality. Therefore, car seat fabric quality grading is a relevant issue to be dealt with downstream to the production line. Nowadays, sponged-like fabric grading is performed by human experts by means of manual inspection and classification; though this manual classification proves to be effective in fabric grading, the process is subjective and its results may vary depending on the operator skills. Accordingly, the definition of a method for the automatic and objective grading of sponged-like fabrics is necessary. The present work aims to provide a computer-based tool capable of classifying sponged-like fabrics, as closely as possible to classifications performed by skilled operators. Such a tool, composed by an appositely devised machine vision system, is capable of extracting a number of numerical parameters characterizing the fabric veins and discoloured areas. Such parameters are, then, used for training an Artificial Neural Network (ANN) with the aim of classifying the fabrics in terms of quality. Finally, a comparison between the ANN-based classification and the one provided by fabric inspectors is performed. The proposed method, tested on a validation set composed by 65 sponged-like fabrics, proves to be able to classify the fabrics into the correct quality class in 93.8% of the cases, with respect to the selection provided by human operators.

Keywords: Artificial neural networks | Car seat fabrics | Grading | Machine vision

[128] Furferi R., Governi L., Palai M., Volpe Y., 3D model retrieval from mechanical drawings analysis, International Journal of Mechanics, 5(2), 91-99, (2011). Abstract
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Computer Aided Engineering (CAE) techniques provide effective solutions for automating the whole product development chain process. Designers, engineers, manufacturing professionals and researchers can now leverage solid modeling data and multi-physics analysis in ways that were inconceivable just few years ago. Among CAE techniques, Computer Aided Design (CAD) has been the most effective in providing methodologies capable of compressing product design and manufacturing cycles, assuring faster turnaround time between design and simulation and improving product quality. Designers and manufacture companies reap the rewards of 3D CAD modelling; as a consequence, research is unceasingly stimulated to look forward. On one hand, research aims to improve capabilities of existing CAD methods and tools; on the other hand novel approaches are extensively investigated with the ambition of carrying out innovative CAD techniques capable of lighting sparking design innovation and creativity. This is particularly true for mechanical design: fast and robust 3D retrieval from 2D drawings that was considered future trend few years ago, is now a key target for commercial software houses like Dassault Systems® and Autodesk® as well as a vigorous focus from an academic outlook. Unfortunately, even if a number of works have been carried out during the last decades, these are mainly described by a conceptual point of view. To derive an orderly procedure covering the necessary steps for retrieving 3D models from mechanical drawings could provide a dramatic boost to researchers and practitioners that introduce this issue on their research. Therefore, the main aim of the present work is to carry out a systematic clear and concise step-by-step procedure for 3D retrieval starting from wireframe models. Since the intent is to afford an as clear as possible, guided, procedure for 3D reconstruction, mathematical description is limited to the simplest case of polyhedral objects. The proposed procedures, inspired by state of the art works, can be effectively contribute to speed-up the possible implementation of methodologies confronting the 3D reconstruction problem.

Keywords: 3D Retrieval | Computational geometry | Computer aided design | Mechanical drawings | Pseudo-wireframe

[129] Furferi R., Governi L., Volpe Y., ANN-based method for olive Ripening Index automatic prediction, Journal of Food Engineering, 101(3), 318-328, (2010). Abstract
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The influence of ripening degree of drupes during the harvesting period is well established in olive oil sector. A range of methods for expressing the stage of maturity of olives have been proposed in scientific literature. One of the most commonly adopted methods provides the evaluation of a Ripening Index (RI) on the basis of olive skin and pulp colour. Unfortunately, the RI evaluation technique is time-consuming, subjective (depending on expert skill) and depends on environmental conditions that may affect colour appearance of olives. This work describes a novel method for rapid, automatic and objective prediction of the Ripening Index of an olive lot. The method integrates a Machine Vision system, capable of performing a colour-based raw prediction of RI, with an Artificial Neural Network (ANN) based algorithm to refine it. Such a refinement is based on a set of chemical parameters (oil content, sugar content and phenol content) which are provided as input to the ANN and which can be obtained by historical curves for the region where the RI needs to be predicted. Experimental results demonstrate the effectiveness of the proposed approach. © 2010 Elsevier Ltd. All rights reserved.

Keywords: Artificial neural networks | Machine vision system | Ripening index

[130] Carfagni M., Governi L., Meiattini D., Volpe Y., A new methodology for computer aided design of fine porcelain whiteware, 2008 Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, DETC 2008, 3(PART A), 151-158, (2009). Abstract
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Fine porcelain products get their peculiar characteristics at the end of their thermal process. During the firing, the product is subjected to shrinkage and a considerable amount of the material mass becomes viscous, causing the product shape to be modified due to the own object weight. As the final object shape is a relevant characteristic for both usability and aesthetics of the commercial product, the activity purpose was to devise a methodology to automatically detect the raw product shape required to match a provided final geometry. Such a methodology has been implemented by means of commercial CAD/FEM tools and should be used in porcelain products design. The research consists of three parts. During the first one an extensive experimental campaign has been carried out in order to model the behavior of the heat treated material; by using the experimental data a numerical model of the material behavior has been built. in the second part the model reliability has been tested by means of a set of FE analysis. Such an analysis simulates the effects of stresses caused by the real industrial firing process. in the end, during the third part, inverse firing process FE simulations have been performed. These simulations will allow the designer to know the raw-product geometry, in order to obtain the expected finished product. .Copyright © 2008 by ASME.

[131] Carfagni M., Governi L., Meiattini D., Volpe Y., A new methodology for computer aided design of fine porcelain whiteware, Proceedings of the ASME Design Engineering Technical Conference, 3(PARTS A AND B), 151-158, (2008). Abstract
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Fine porcelain products get their peculiar characteristics at the end of their thermal process. During the firing, the product is subjected to shrinkage and a considerable amount of the material mass becomes viscous, causing the product shape to be modified due to the own object weight. As the final object shape is a relevant characteristic for both usability and aesthetics of the commercial product, the activity purpose was to devise a methodology to automatically detect the raw product shape required to match a provided final geometry. Such a methodology has been implemented by means of commercial CAD/FEM tools and should be used in porcelain products design. The research consists of three parts. During the first one an extensive experimental campaign has been carried out in order to model the behavior of the heat treated material; by using the experimental data a numerical model of the material behavior has been built. In the second part the model reliability has been tested by means of a set of FE analysis. Such an analysis simulates the effects of stresses caused by the real industrial firing process. In the end, during the third part, inverse firing process FE simulations have been performed. These simulations will allow the designer to know the raw-product geometry, in order to obtain the expected finished product. Copyright © 2008 by ASME.