3D technologies for cultural heritages

In the last years, museums have begun to apply new technological solutions to manage their exhibits in a more open, inclusive, and creative way, to improve the visitors' experience to respond to the need to expand the audience. The main goal is to face the increasing competition in an economy referred to as the “Experience Economy”. To this end, Augmented Reality technology seems to represent a good solution for museum guide systems, to improve visitors' learning and enjoyment. In this context, the present paper proposes a museum guide system based on Spatial Augmented Reality powered by dynamic projection. The paper describes the overall HW and SW system architecture and reports in detail the developed process adopted to design and implement a museum guide and entertainment application, in the context of the “Studiolo of Federico da Montefeltro” in the Ducal Palace of Urbino. A preliminary survey has been carried out, which involved a total of 79 subjects, aimed at investigating the quality of visitor's experience, aroused by the proposed application, in terms of the “Four Experience Realms” defined by Pine & Gilmore (1998). Results suggest that the proposed application can be used to stage experiences that satisfy the visitors and may help to enable museums into the Experience Economy.

Keywords: Cultural heritage , Dynamic projection , Experience economy , Museum guide , Spatial augmented reality

Virtual museum systems, based on different X-reality technologies, has begun to spread, as they represent decisive tools to promote exhibitions and reaching out to audiences. Although budgetary considerations have so far limited the choice of technologies a wide range of possible technological options are available today at low cost. This paper provides the results of an empirical study, with the aim to determine the most appropriate technologies to satisfy the visitors' expectation and maximise their likelihood to repeat and recommend the experience. The study focuses on the comparison of the performance of five VM systems for visualise digital reproduction of archaeological finds, based on different technologies (i.e., PC desktop, holographic display, 3D stereoscopic projection, head mounted display and mobile Augmented Reality). The results provide useful insight for the development of VM systems, in order to maximize the visitor experience in terms of presence and ability to activate an experience economy perspective.

Keywords: Augmented reality , Mixed reality , Presence , Virtual Museum , Virtual reality , Visitor experience , X-Reality technologies

Traditionally, duplicating handmade artefacts was done primarily by moulds. To obtain multiples of the casts, the artisan laid out a layer of clay over the mould and pressed on it strongly to make sure of thorough contact. The moulds found by excavation show wear due to compression and deterioration over time. They often disintegrate and are unusable. Consequently, understanding and studying the images they contain is only possible when the moulds are re-useable for casts which, to date, are carried out in restoration laboratories by traditional techniques. It should be noted that apart from the casts' shrinking, moulds are also subject to altered sizes and morphologies after extraction from the archetype and therefore at the end of the production line the cast image is all the more blurred due to a loss of detail. This study describes a multidisciplinary approach applied to two clay moulds from classical antiquity that differ in size and shape, and the casts they produce using traditional techniques. Using Reverse Engineering (RE) by 3D laser scanning, a computer-based method was applied to study their morphometric relationship only obtainable in a virtual environment without compromising the integrity of the physical models. Furthermore, the digitalised moulds have provided virtual casts without significant size alterations for the aims of this work, making them ‘ideal' casts. These last casts were then converted by Rapid Prototyping (RP) into physical prototypes which have negligible geometric errors for making multiple replicas for educational or exhibition purposes. In archaeology, this method offers researchers the opportunity to study and acquire morphological data which the moulds themselves cannot, nor can their casts. So, it is possible to go back in time to images which match their archetypes even without their casts. More detailed knowledge about the form of an art object is important for its study, conservation and how it was produced. So, ancient clay moulds are studied particularly in investigating methods of mass production, their social value and the degree of specialisation of those ancient societies.

Keywords: 3D laser scanning , 3D technology in archaeology , Ancient mould , Cultural heritage survey , Morphometric analysis , Virtual model

Underwater cultural heritage sites represent an attractive and exciting experience for diving tourists, even if often it is complicated for them to understand the significance and value of the remains that are usually strongly damaged and covered by the marine organisms. Thanks to the recent advancements in technologies that overcome these problems, augmented reality is nowadays possible even in such harsh conditions, opening new possibilities for enhancing the diver's experience. However, no user study has formally evaluated the usefulness and usability of augmented reality in open sea underwater environments. This paper presents two novel solutions for underwater augmented reality: a compact marker-based system for small areas, and a complex acoustic system for large areas. Both of them were deployed at an underwater cultural heritage site and evaluated by ten divers in experiments analyzing their perception and remembrance, interests, and user experience. For comparison, the same study was also performed with non-divers assessing the marker-based system on land. Results show that both systems allow divers to encounter new and exciting moments and provide valuable insights for underwater augmented reality applications.

Keywords: Augmented reality , cultural heritage , sensor fusion , underwater , user experience , user testing

Current conservation approaches are shifting toward small, tailored, and less invasive interventions. Therefore the problems and best practices for conservators are becoming increasingly mobile. The future of art preservation heating systems will be with “intelligent” devices that are portable, flexible, reliable, and cost-effective. In this scenario, flexible heaters are becoming the preferred device for the application of heat in restoration since they can be shaped in different geometries and sizes, are easy to be transported and can be applied in the most versatile way with other treatment devices. Moreover, such devices can be applied also for in situ treatments, for instance, in emergency interventions. The development of these flexible devices comes from the past and, therefore, has a long history. To provide the reader with a comprehensive description of most innovative heating devices for art conservation, this chapter provides a brief history on how such devices evolved from the beginning to now, with the final aim of understanding the technological challenges and issues that allowed to continuously improve traditional heat tables and wound wire-based blankets toward the creation of innovative carbon nanotubes (CNTs)-based devices. After an historical investigation of heating devices, mostly based on heat tables, the chapter focuses on current technologies where nanomaterials are increasingly being used to boost the heating performance in several fields of application. Finally this work describes the main outcomes of a recent European Project, which applied CNTs-based coating on flexible substrates to create the first prototypes of intelligent mobile heaters to be adopted extensively by conservators. A number of applications of this new kind of device are eventually proposed and discussed.

Keywords: Carbon nanotubes , Coatings , Cultural heritage , Heating mat

Cosmic ray radiation, thanks to its high penetration capability and relative abundance, has been successfully used in scientific research and civil applications for a long time. For example, techniques based on the attenuation of cosmic ray muons or on their angular scattering have been used to study the inner structure of volcanoes, to search for hidden chambers in Egyptian pyramids, to inspect nuclear waste containers and to monitor blast furnaces. In addition to these imaging techniques, cosmic ray muons have also been used for the detector alignment in large experiments in nuclear and elementary particle physics. In this context, a cosmic muon detection system for the stability monitoring of historical buildings will be here presented. The employment of cosmic rays is envisaged where the time scale of deformations is typically very long, and where conservation constraints could prevent the use of standard mechanical systems. The stability monitoring of Palazzo della Loggia (Brescia, Italy) has been considered as a case study, and performance and limitations of the technique have been evaluated using Monte Carlo (MC) simulations. A muon detection system based on two telescopes with three sensitive layers of scintillating fibers coupled to silicon photomultipliers has been studied. Results from MC studies, taking into account systematic uncertainties, are here presented. Finally, the main features and performance of a small-size detector prototype, developed as a proof of principle and consisting of three layers of 3x3 mm2 scintillating fibers, as those used in the simulations, are also described.

Potteries are the most numerous finds found in archaeological excavations; they are often used to get information about the history, economy, and art of a site. Archaeologists rarely find complete vases but, generally, damaged and in fragments, often mixed with other pottery groups. By using the traditional manual method, the analysis and reconstruction of sherds are performed by a skilled operator. Reviewed papers provided evidence that the traditional method is not reproducible, not repeatable, time-consuming and its results have great uncertainties. To overcome the aforementioned limits, in the last years, researchers have made efforts to develop computer-based methods for archaeological ceramic sherds analysis, aimed at their reconstruction. To contribute to this field of study, in this paper, a comprehensive analysis of the most important available publications until the end of 2019 is presented. This study, focused on pottery fragments only, is performed by collecting papers in English by the Scopus database using the following keywords: "computer methods in archaeology", "3D archaeology", "3D reconstruction", "automatic feature recognition and reconstruction", "restoration of pottery shape relics". The list is completed by additional references found through the reading of selected papers. The 53 selected papers are divided into three periods of time. According to a detailed review of the performed studies, the key elements of each analyzed method are listed based on data acquisition tools, features extracted, classification processes, and matching techniques. Finally, to overcome the actual gaps some recommendations for future researches are proposed.

Keywords: 3D archaeology , 3D reconstruction , Automatic feature recognition and reconstruction , Computer methods in archaeology , Restoration of pottery shape relics

The registration permits to positioning in a single reference system point clouds acquired from different points of view. Since this is typically obtained with an iterative numerical method, it represents an important source of error in the entire reverse engineering process. As all iterative methods, such errors depend on the choice of the initial solution; therefore, this process requires an expert user who, by using dedicated software, choices the sequence of clouds to be registered, imposes for each pairwise the first attempt registration, launches the iterative method, and verifies the final result. With the aim to minimize the error and the user's interaction, some devices are proposed in the market (turntable or the anthropomorphic arm, etc.). The above-mentioned hardware and software tools cannot be used in the cultural heritage applications involving large and detailed objects. In this paper, an automatic alignment method of point clouds is proposed. The method uses as inputs the constant radius features, which are frequently detectable on cultural heritage objects. The automatic alignment of the point clouds is based on the recognition, the segmentation, and the registration of the sweep lines identifiable from these features.

This paper presents a combined subjective and objective evaluation of an application mixing interactive virtual reality (VR) experience with 360â—¦ storytelling. The hypothesis that the modern immersive archaeological VR application presenting cultural heritage from a submerged site would sustain high levels of presence, immersion, and general engagement was leveraged in the investigation of the user experience with both the subjective (questionnaires) and the objective (neurophysiological recording of the brain signals using electroencephalography (EEG)) evaluation methods. Participants rated the VR experience positively in the questionnaire scales for presence, immersion, and subjective judgement. High positive rating concerned also the psychological states linked to the experience (engagement, emotions, and the state of flow), and the experience was mostly free from difficulties linked to the accustomization to the VR technology (technology adoption to the head-mounted display and controllers, VR sickness). EEG results are in line with past studies examining brain responses to virtual experiences, while new results in the beta band suggest that EEG is a viable tool for future studies of presence and immersion in VR.

Keywords: 360-video storytelling , Cultural heritage , EEG , Immersion , Presence , Virtual reality

Automatic painting classification by author, artistic genre and/or other attributes has generated considerable research interest in recent years. Being one of the visual features that mark the difference between artists and artistic genres, colour plays a fundamental role in this process. Colour is the result of the interaction among the intrinsic properties of the material, the illumination conditions and the response of the imaging device. Consequently, the same painting/artwork will look significantly different when imaged under varied conditions, which can be a potential source of bias for automated recognition procedures. One can compensate for such variations either via colour calibration or colour pre-processing. In this work we investigate the latter, and, in particular, evaluate the effectiveness of colour constancy and colour augmentation when coupled with hand-crafted and deep learning features for painting classification by artistic genre. In our experiments neither approach showed a clear advantage compared with no pre-processing at all. Colour constancy brought some improvement in certain cases, whereas colour augmentation virtually provided no benefit despite its adding a significant computational overload to the procedure.

Close-Range Photogrammetry is a widespread and efficient technique in the 3D acquisition of artefacts, particularly in fields like Cultural Heritage. Despite this wide usage, also due to a convenient quality/cost ratio, it shows some limitations due to light conditions as well as the artefact surface finishing. In this paper, we would like to report the assessment of a photogrammetry approach to 3D capture metal reflective surfaces, such as bronze, which is a widely used material in ancient statues. To this aim, we propose a photogrammetry workflow based on systematic steps capable of overcome some of the main issues of reflective surfaces. To validate this approach, the developed 3D model is compared to a more accurate model of the same artefact, obtained with a 3D scanner. As a case study, we selected the Principe Ellenistico, an ancient bronze statue conserved in the Museo Nazionale Romano (Rome, Italy), of which a photogrammetric model is firstly developed and then compared to the scanned one.

Keywords: 3D acquisition , Bronze statue , Close-Range Photogrammetry , Principe Ellenistico , Systematic approach

The introduction of two-wheel chariots, pulled by horses, was a key technological innovation in the Bronze Age. Archaeological evidences, found in Northern Africa, Europe and Asia, allowed identifying various chariot typologies and understanding their main features. However, many questions about the function of single pieces and the behavior of the vehicles are still open. In a previous work, a war chariot wheel, found in northern Italy and known as the “Mercurago wheel”, was studied with an engineering approach. In this paper, the whole vehicle, to which the wheel was hypothesized to belong, was studied. In particular, two chariot typologies, differing mainly for the axle position, were analyzed. The stiffness of the various chariot parts were characterized by means of static finite element analyses. These data were subsequently used as input parameters in running multibody dynamics simulations. Finite element dynamical simulations were carried out as well. The analyses results allowed determining the crucial effect of some parts, particularly the cockpit floor, in favoring the passenger stability in dangerous conditions, such as bumping. The effect of the axle position on the passenger and wheel trajectory were evaluated as well.

Kandinsky-Experience Book is a multisensory Augmented Reality experience that involves sight, hearing and smell senses and aims at improving the users' engagement in the Kandinsky's artworks. Specifically, the aim of the application is to augment the experience of the user creating a journey throughout Kandinsky's work by using an AR application for smartphones integrated with audio and olfactory stimuli, in order to allow him/her to be more immersed in the piece of art. The research project has been inspired by the synesthetic approach of the abstract painter to the theory and the perception of art in his books. Starting from the artist's considerations about the relationship between different sensorial stimuli in works of art, we decided to amplify some of his theories suggesting a connection between the main pictorial elements and some corresponding olfactory stimuli, grounding our hypotheses on the content of papers concerning the crossmodal synesthetic correspondences between olfactory stimuli and other sensorial modalities. Thanks to the simultaneous presentation of the specifically developed AR contents and the olfactory stimuli, the users' feelings and emotions during the experience are amplified as a result of the sensory integration. Moreover, by using AR technology and olfactory devices to stimulate visual and olfactory perceptual channels we aimed at increasing the generation of longer-lasting memories in the users' mind.

Keywords: Augmented Reality , Cultural Heritage , Multisensory Perception , User Experience

Interactive multimedia applications in museums generally aim at integrating into the exhibition complementary information delivered through engaging narratives. This article discusses a possible approach for effectively designing an interactive app for museum collections whose physical pieces are mutually related by multiple and articulated logical interconnections referring to elements of immaterial cultural heritage that would not be easy to bring to the public with traditional means. As proof of this concept, a specific case related to ancient Egyptian civilization has been developed. A collection of Egyptian artifacts such as mummies, coffins, and amulets, associated with symbols, divinities, and magic spells through the structured funerary ritual typical of that civilization, has been explained through a virtual application based on the concepts discussed in the methodological section.

Keywords: Ancient Egypt , Cultural heritage exhibition , Digital heritage , Intangible heritage , Interactive devices , Multimedia , Virtual museum

Ceramic sherds are the most common finds in archaeology. They are complex to analyze and onerous to process. A large number of indistinct sherds coming from excavations must be preliminarily grouped in some categories. This clusterization helps the next phase, in which archaeologists classify the ceramics. Due to the difficulty of these preliminary, repetitive, and routine phases, a great deal of archaeological material remains unstudied in museum repositories or archaeological sites. An effective method to automate these routine phases is presented in this article. The proposed method performs a shape feature segmentation of the sherds, which is fundamental to undertake any further analysis, such as potsherds classification, reconstruction, or cataloging. A set of specific shape features, useful to understand the find properties, is defined and methods for recognizing them are proposed. The method's performance is tested in the analysis of some real, critical cases.

Keywords: 3D archaeology , Automatic feature recognition , computer methods in archaeology , surface segmentation

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

In the field of cultural heritage, operators make use of high resolution orthophotos of paintings both for purposes related to restoration and monitoring of art pieces and for realizing online documentations and exhibitions. Unfortunately, artworks to be restored and/or presented in digital museums are painted on canvas which are far to be perfectly planar. Therefore, technical documentation accompanying an artwork to be stored in digital archives or museums can be enriched by information related to the 3D shape of the canvas. In this paper, both the design of a portable low-cost device that allows the acquisition of the 3D geometry of the painting and a procedure to triangulate 3D data are proposed. Such a procedure, working using the principle of laser-camera triangulation, is based on the use of a set of fiducial markers to set and continuously control the reciprocal orientation of the laser source and of the camera.

Keywords: 3D laser scanner , Cultural heritage , Marker detection , Pose estimation , Reverse engineering

Very often historical buildings used as museums are characterized by rooms completely covered with decorations (e.g. frescoes, inlay, etc.) rich in details and symbolic contents. Providing adequate information to the visitors to allow them to fully appreciate the artworks is of paramount importance in this context. X-reality technologies have the potential to provide an effective response to the need to combine the educational mission of museums with the ability to involve visitors emotionally, allowing the public to learn new knowledge in a playful way. This study introduces a Museum Guide System, based on Dynamic Projection, to increase the involvement of visitors to the Studiolo by Federico da Montefeltro at Urbino, minimizing technology intrusiveness by ensuring a complete fusion of digital contents with the physical environment. The system is able to track the visitors, to detect their profile and to offer information and multimedia contents tailored to the characteristics of the audience (e.g., children, adults).

Keywords: Adaptive system , Digital Cultural Heritage , Dynamic projection , Museum Guide System , Spatial Augmented Reality

The aim of this study was to confirm the identities of numerous portraits attributed to the composer Vincenzo Bellini by using 3D-to-2D projection. This study also followed on from earlier research on three death masks of Bellini, the results of which had shown that the wax mask in Catania's Bellini museum best represented Bellini's face compared to the other two. This study used the aforementioned 3D wax death mask obtained through Reverse Engineering as a reference for a morphometric comparison with 14 other portraits. For each portrait, the linear 3D-to-2D transformation M was found which minimized the distance between the 2D landmarks in the picture and the projected landmarks on the 3D mask. This normalized the distances considering the scale of the portrait and the final dissimilarity score with the mask. In particular, the analytical results were able to identify two portraits which particularly resembled the 3D death mask providing future researchers with the chance to carry out historical-artistic evaluations. We were also able to develop a new tool – Image Mark Pro - to easily annotate 2D images by introducing landmark locations. Since it was so reliable for manually annotating landmarks, we decided to make it publicly available for future research.

Keywords: 3D death mask , 3D-2D comparison , Face recognition , Landmarks projection

The preservation of cultural heritage often involves the design of systems with different purposes, as for example the devices for extraction of data from inaccessible locations and/or demonstrative models. For the latter, when the starting information about the model to be designed is incomplete, the task is not trivial, and different interpretations of the system can lead to different design outcomes. Moreover, other requirements concerning size, materials and interactivity, make this a real engineering design task, where actors with conflicting needs can be involved. Accordingly, to ensure a comprehensive fulfilment of the task, it is possible to follow engineering systematic design approaches that, even if originally developed for the development of industrial systems, can be conveniently used for different fields of application. More specifically, these design methods ensure the design of cost-effective solutions by reducing the useless and costly design iterations that often characterize non-structured procedures. In particular, the present paper shows the application of systematic methods for the interpretation, the design and the development of realistic physical models from some of the Leonardo da Vinci's machines, for the Museo Leonardiano of Vinci (Italy). The followed approach allowed to efficiently gather the starting list of design requirements, and to engage a successful interaction among the designers, the historians, the museum staff and the architect involved in the showroom design. The key points of the systematic design methodology are presented in this paper, together with some applicative examples from the Da Vinci's models. Other possible application of systematic design approaches are also presented, with the aim of showing some representative examples were the Engineering design and problem-solving methods can support the preservation of cultural heritage.