3D technologies for cultural heritages

With the aim to reduce the uncertainties of the traditional archaeological approach and reduce costs for ceramic investigation, in this paper a computer-based method is proposed. A discrete geometric model of a pottery fragment is the starting input, from which a first distinction in axially and not-axially symmetric surfaces can be done. Geometrical and morphological features are then recognized. Only once that all this information is obtained, it is possible to proceed with the dimensional analysis. The analysis carried on the test case here illustrated proves that the automatic method presents accuracy and robustness not achievable even using the best application of the archaeological method. This method seems to be functional to other goals, such as for pottery classification and reconstruction of ancient ceramics.

Keywords: 3D archaeology , Automatic feature recognition , Computer methods in archaeology , Surface segmentation

In this paper, a method for determining the best choice of the 3D scanner for cultural heritage applications is presented. Generally speaking, this activity is not trivial since a 3D scanner that matches all the requirements of a typical preservation activity in cultural heritage does not exist. Thus, to the best of the authors' knowledge, the choice of compromise is typically performed in an unstructured way. In order to structure this choice, a method based on the Analytic Hierarchy Process (AHP) is proposed. In the proposed method, the three levels of the AHP hierarchy structure are the selection of the best 3D scanner for a specific cultural heritage application (goal), the most important technical parameters that mainly affect the choice of a 3D scanner (criteria), and the devices matching the required resolution (alternatives). Having defined the goal, prioritization of the type and quality of information is performed by the team leader of the research group (typically a skilled archaeologist), while the priority of the pairwise comparison among alternatives is decided by an expert on 3D scanners. The application of the proposed method in two contrasting situations concerning pottery fragments highlights its ease of use, its robustness (confirmed by the consistency analysis), and the completeness of the technical and economic assessment (since all relevant elements are taken into account), which put together, in a structured way, competences in very different fields (archaeology and 3D digital devices).

Keywords: 3D archaeology , Analytic Hierarchy Process (AHP) , Choice of best 3D scanners

Constant radius geometric features are a common type of manufacturing features of ancient ceramics. They are obtained by a sweeping action of a tool, which leaves negative or positive traces characterized by a cross-section with one or more constant radii. The automatic recognition and dimensional characterization of these features could be useful for understanding the technology used to manufacture ceramics. Thus, a new perspective in archaeological investigations can be furnished. For this purpose, in this paper a new computer-based methodology suited to segmenting constant radius geometric features and measuring their dimensional parameters is proposed. Starting from a 3D discrete geometric model of the ceramic, the region pertaining to these features is determined and measurements of their radii are performed. Due to the uncertainties of various sources, which affect the investigated object, the required process is not trivial. In order to solve this problem, the segmentation phase is conducted using a non-conventional logic suitable for exploring the object with a fuzzy sensitivity, and the measurement is performed by a robust fitting method applied to the segmented entities. The methodology has been tested in the identification of embossed decorations of an ancient olla. The combined effects of the feature segmentation process together with the measure detection approach on the obtained results are critically analyzed and discussed.

Keywords: Computer methods in archaeology , Fuzzy logic , Geometric features recognition , Metrology for cultural heritage

The construction of artificial emissary of Lake Fucino's represents one of the most significant engineering challenges that took place in antiquity. Unfortunately, the imposing structure of the Roman emissary was almost completely erased from the building of the late nineteenth century, constructed for the final drying of the lake. This article presents its virtual reconstruction, to understand the technological issues met by Romans and to visually offer reconstruction theories starting from interpreting of the few Roman remains. So that, engineering resources are used to try to understand unresolved issues in archaeology.

In this paper, a new method for axis detection of discrete thin-walled axially symmetric surfaces is presented. This method is based on the property of thin-walled axially symmetric surfaces that the minimum path of a point on the external wall to the internal wall is on a straight line passing through the axis. This working principle, since it does not require the evaluation of differential geometrical properties, makes the method robust to noise. The proposed method has been applied in a very critical application area: axially symmetric archaeological pottery fragments, for which the evaluation of the axis is complex because of manufacturing error and of modification of the surface properties due to the action of time and weather. The trueness of the proposed method is compared with those of the five methods presented in the literature in the analysis of real sherds of various dimensions and conditions. The proposed method demonstrates greater robustness than these methods and is shown to be promising to improve the number of sherds that can be successfully analyzed.

Keywords: 3D archeology , Axis estimation , Computer , Geometric inspection , Methods in archaeology

The manual drafting of lithics artefacts could be a very time-consuming work, and it could be cumbersome on the archaeological site. In this case, a 3D digital model of the object could be very useful. Nowadays, several digitizing technologies are available to easily acquire information about the shape of an object. Virtual models could be used to create a digital museum or to share information between researchers. On the other hand, the manual drafting of a lithic object contains information about the technologies used to realize it. Information about the core setup, types of chipping surfaces, detach sequence of supports, and much more. In this work a method to easily obtain a hand-made-like draft of lithic artefacts is proposed. The method is based on the 3D acquisition of the object with a structured-light based scanner and a sequence of digital processing of the acquired data.

Ancient wooden panel paintings are an essential part of our cultural heritage. Wood as artworks support has always been very popular and painted panels are largely diffuse in many churches and museums. However, depending on conservation conditions, the wooden panels shape may vary and, if not properly controlled, may lead to some sever damage to the artworks. This paper presents the results of a study on the measurement of paintings surface deformation carried out using two different three-dimensional acquisition devices both making use of structured light. The main goal was to highlight and measure the reliability of such 3D measuring techniques to evaluate deviations from planarity due to the curving and warping of the wood and to document spatial deformation suffered by the painting and monitoring its conservation status.

The paper presents a virtual diving system based on a virtual reality (VR) application for the exploitation of the Underwater Cultural Heritage. The virtual diving experience has been designed to entertain users, but its added pedagogical value is explicitly emphasized too. In fact, the ludic activities, consisting in the simulation of a real diving session from the point of view of a scuba diver, are following a storyline described by a virtual diving companion who guides users during the exploration of the underwater archaeological site. The virtual diving system provides general and historical-cultural contents, but also information about the flora and fauna of the specific submerged site to the users. The results collected through user studies demonstrate that the proposed VR system is able to provide a playful learning experience, with a high emotional impact, and it has been well appreciated by a large variety of audiences, even by younger and inexperienced users.

Keywords: Serious games , Underwater archaeological sites , Underwater Cultural Heritage , Virtual diving system , Virtual reality

Nowadays, the adoption of virtual reality (VR) exhibits is increasingly common both in large and small museums because of their capability to enhance the communication of the cultural contents and to provide an engaging and fun experience to its visitors. The paper describes a user-centered design (UCD) approach for the development of a VR exhibit for the interactive exploitation of archaeological artefacts. In particular, this approach has been carried out for the development of a virtual exhibit hosted at the “Museum of the Bruttians and the Sea” of Cetraro (Italy). The main goal was to enrich the museum with a playful and educational VR exhibit able to make the visitors enjoy an immersive and attractive experience, allowing them to observe 3D archaeological artefacts in their original context of finding. The paper deals with several technical issues commonly related to the design of virtual museum exhibits that rely on off-the-shelf technologies. The proposed solutions, based on an UCD approach, can be efficiently adopted as guidelines for the development of similar VR exhibits, especially when very low budget and little free space are unavoidable design requirements.

Keywords: Human–computer interaction , User interface design , User-centered design , Virtual museum systems , Virtual reality

The ever increasing availability of digital data from the Arts and cultural heritage calls for efficient methods to organise, categorise, and retrieve such information in an effective and reliable way. In this context, painting classification has attracted significant research interest in recent years. In this work we address the problem of style classification, which involves determining the school, period and art movement to which a painting belongs. Notably, this job is peculiarly different from other machine vision applications - such as material, object and scene recognition - since the concept of 'similarity' is much more difficult to define in this case. For this specific task we evaluate, in this study, the effectiveness of an array of hand-designed visual descriptors against a set of feature extractors based on last-generation convolutional neural networks. We also investigate the effect of pre-processing methods such as image split and pyramidal decomposition. The experiments are based on the open-access Pandora dataset. The results show that pre-trained models can significantly outperform hand-designed descriptors with overall accuracy surpassing 67%. This represents an improvement on the state-of-the-art by ≈12 percentage points.

Ancient bronze statues mainly require material integrity assessment and restoration. Restoration may include also the update of the museum exhibition, defining new structural frames and fragment re-composition to preserve the statue and improve the interpretation of the original aspect. This paper proves how engineering methods (such as Finite Element Analysis, Computer Aided Design modelling, Reverse Engineering) may assist cultural heritage experts and restorers in these tasks. It presents the activities made together with the Museo Nazionale Romano and the Istituto Superiore per la Conservazione e il Restauro, on the so-called "Principe Ellenistico" (Hellenistic Prince). This bronze was found in pieces (body, left arm and right leg), at the end of 19th century during an excavation made in Rome. No visual or reference sources can say its origin and its final posture was defined by restorers at the end of the 19th century according to their hypothesis and studies. In the 20th century, a further restoration was made on the critical areas of the surface, together with some structural improvement of the inner frame. Nowadays, after a review of its position inside the Museum, new experimental and numerical analyses have been carried out to better understand surface weakness and correct left arm positioning.

One of the most effective strategies that can be adopted to make successful cultural heritage expositions consists in attracting the visitors' attention and improving their enjoyment/engagement. A mid-air gesture-based Natural User Interface was designed, through the user-centric approach, for the navigation of virtual tours in cultural heritage exhibitions. In detail, the proposed interface was developed to “visit” Murgia, a karst zone lying within Puglia, very famous for its fortified farms, dolines, sinkholes, and caves. Including an “immersive” gesture-based interface was demonstrated to improve the user's experience thus giving her/him the sensation of “exploring” in a seamless manner the wonderful and rather adventurous sites of Murgia. User tests aimed at comparing the implemented interface with a conventional mouse-controlled one confirmed the capability of the proposed interface to enhance the user engagement/enjoyment and to make “more” natural/real, the virtual environment.

Keywords: Gesture vocabulary design , Natural user interface , User-centric approach , Virtual tour

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

The visualization and analysis of mosaics and pavements are often compromised by their large sizes, which do not enable the observer to perceive their whole arrangement or to focus on details placed in farthest areas from its boundaries. Moreover, the usual precarious state of conservation of these artefacts, often with damaged or missing areas, makes it difficult to perceive their original aesthetic value. To overcome these limitations, we propose an application of augmented reality able to support the observer in two ways: first, the application completes the missing surface of the mosaic or pavement by integrating the existent surface with a virtual reconstruction; second, it enables the analysis of the geometric pattern of the mosaic/pavement by overlaying virtual lines and geometric figures in order to explicit its geometric arrangements. The result is achieved via a custom Android application able to recognize and track the mosaic figure pattern and extra marker board, obtaining in that way a coordinate system used to render in real-time the reconstruction of the mosaic. Such rendering is overlaid to the video stream of the real scene. The application runs on a standard smartphone embedded in a Google Cardboard-compatible viewer and therefore is extremely affordable. As a case study, in order to reconstruct its aspects and to analyse its geometric pattern, we chose the roman mosaic re-found in Savignano sul Panaro (near Modena, Italy) in 2011, after 115 years from its first discovery, which is preserved less than half of its original 4.5 x 6.9 m surface.

Keywords: Augmented Reality , Cultural heritage , Geometric pattern , Photogrammetry , Real-time visualization , Roman mosaic

This paper proposes the integration of photogrammetric reconstruction, 3D modelling and augmented reality application in order to achieve the complete visualization of a stone sculpture even if highly damaged or fragmentary. The first part of the research aims to the reconstruction of the original aspect of an incomplete sculpture, by using photogrammetry techniques based on standard resolution photos and free software in order to obtain a first model; then, we integrate this model with other 3D digital data (from other sculptures of the same period) or with 3D modelling based on historical sources and views from historians, aiming to achieve the original aspect of the sculpture. The second part of the research consists of the embedding of the obtained model in a custom application able to render in real-time the 3D reconstruction of the lion. Then, the rendering is overlaid to the video stream of the real scene and, as a result, a complete 3D digital model of the sculpture is achieved and could be visualized through a VR viewer. As a case study, we focus on a Roman stone sculpture of a male lion conserved in the Museo Estense of Modena (Italy), which lacks of its head and its four legs. The original aspect of the lion may be achieved by integrating the damaged sculpture with other photogrammetric reconstructions of lions sculptures of the same period and with 3D model based on historical sources. Finally, the lion is visualized through an augmented reality application which digitally overlays the reconstructed models on the original one.

Keywords: Augmented Reality , Cultural heritage , Photogrammetry , Real-time visualization , Virtual modeling

Lab4Dive project aims to design, develop, and validate an innovative, marketable and competitive product for supporting underwater archaeologists in surveying, documenting and preserving the underwater cultural heritage. These activities could be improved considerably with the introduction of new technological devices and tools, helping underwater archaeologists to collect data from the marine environment. The project will provide a solution by equipping divers with portable, low cost and relatively small sized data-gathering systems (i.e. environmental sensors, acoustic localization system, HD cameras, etc.), so they can significantly improve both the amount of data collected in a single mission and the management of time and human resources at disposal. In this paper, the preliminary developments and the tests of the Lab4Dive system will be presented, which is mainly based on two modules: Cloud Server Module and the Underwater Module. The latter is based on two systems: an underwater tablet, that supports the diver during the immersion providing an augmented navigation interface that guides the diver along the selected targets; and a Docking Station, to acquire and exchange data coming from different environmental sensors, a high-resolution camera and an acoustic localization system, physically connected to it.

The Underwater Cultural Heritage represents a key aspect of our historical memory still little known due to a number of limitations imposed by the underwater environment. The aim of this paper is to explore the use of digital three-dimensional reconstructions to support the research about this immeasurable archaeological and historical resource. The whole virtual reconstruction process is described step by step, focusing on the iterative feedback allowing for reaching the best virtual reconstruction solutions, helping the archaeologists to better focus their reasoning through a detailed visual representation, and the technical experts to avoid misleading details in the final virtual reconstruction.

UCRCA - Underwater Cultural Routes in Classical Antiquity" is an eu project financed through the easme-emff fund in order to promote the creation of touristic thematic itineraries linked to the underwater archaeological heritage. It aims to enhance the sustainability of the touristic sector in coastal and maritime areas through the broadening of the cultural tourism offer, thanks to the creation of underwater itineraries for recreational diving activities. Four pilot sites bearing specific characteristics have been chosen to create and launch a new touristic product, two in Greece and two in Southern Italy. Alonissos Island (Sporades), Methoni (Peloponnese), San Pietro in Bevagna (Puglia) and Crotone (Calabria) are four popular holiday destinations in the Mediterranean Sea, whose archaeological underwater sites are still unnoticed by the greater audience. Before creating archaeological underwater itineraries, the Italian Institute for the Conservation and Restoration (MiBAC-iscr) and the Department of Mechanical and Management Engineering of the Calabria University (dimeg-unical) carried out several years of activities linked to the research and test of new methods and technologies for the in situ conservation of the underwater artifacts.

Keywords: European community , In situ preservation , Responsible tourism , Shipwrecks , Underwater archaeological heritage , Underwater archaeology , Underwater restoration , Underwater tourism

The dimensional characterisation of pottery is usually necessary to typify finds and also to recognise sherds pertaining to the same object. With the aim of reducing the uncertainties that typically affect the measurement carried out by the approach traditionally performed by archaeologists, we propose a new automatic method for dimensional characterisation of pottery fragments. The method, starting from a 3D-scanned high point density model, takes advantages from the preventive segmentation and recognition of its significant geometric features; the corresponding characteristic dimensions are evaluated by dedicated procedures. The dimensions measured are also those typically evaluated by archaeologists. In order to quantify the performances of the proposed method, a comparison of its repeatability and reproducibility is made with respect to the traditional manual approach. The proposed method, tested in some real critical cases, demonstrates better performances and lower uncertainties with respect to the traditional approaches.

Keywords: 3D archaeology , Automatic feature recognition , Computer methods in archaeology , Measurement precision in archaeology , Pottery profile , Surface segmentation

For the purpose of reducing uncertainties in the measurements of morphologically complex biological objects, the authors present a new automatic method, which takes advantage from the representation of the object in the form of the 3D geometric model obtained from CT-scans or 3D scanning. In this paper, the method is verified in real cases and compared with the traditional approaches.

Keywords: 3D biomedical image analysis , measurement accuracy , measurement protocols in biomedicine , shape segmentation