3D photogrammetric data modeling and optimization for multipurpose analysis and representation of Cultural Heritage assets

This research deals with the issues concerning the processing, managing, representation for further dissemination of the big amount of 3D data today achievable and storable with the modern geomatic techniques of 3D metric survey. In particular, this thesis is focused on the optimization process applied to 3D photogrammetric data of Cultural Heritage assets. Modern Geomatic techniques enable the acquisition and storage of a big amount of data, with high metric and radiometric accuracy and precision, also in the very close range field, and to process very detailed 3D textured models. Nowadays, the photogrammetric pipeline has well-established potentialities and it is considered one of the principal technique to produce, at low cost, detailed 3D textured models. The potentialities offered by high resolution and textured 3D models is today well-known and such representations are a powerful tool for many multidisciplinary purposes, at different scales and resolutions, from documentation, conservation and restoration to visualization and education. For example, their sub-millimetric precision makes them suitable for scientific studies applied to the geometry and materials (i.e. for structural and static tests, for planning restoration activities or for historical sources); their high fidelity to the real object and their navigability makes them optimal for web-based visualization and dissemination applications. Thanks to the improvement made in new visualization standard, they can be easily used as visualization interface linking different kinds of information in a highly intuitive way. Furthermore, many museums look today for more interactive exhibitions that may increase the visitors’ emotions and many recent applications make use of 3D contents (i.e. in virtual or augmented reality applications and through virtual museums). What all of these applications have to deal with concerns the issue deriving from the difficult of managing the big amount of data that have to be represented and navigated. Indeed, reality based models have very heavy file sizes (also tens of GB) that makes them difficult to be handled by common and portable devices, published on the internet or managed in real time applications. Even though recent advances produce more and more sophisticated and capable hardware and internet standards, empowering the ability to easily handle, visualize and share such contents, other researches aim at define a common pipeline for the generation and optimization of 3D models with a reduced number of polygons, however able to satisfy detailed radiometric and geometric requests. iii This thesis is inserted in this scenario and focuses on the 3D modeling process of photogrammetric data aimed at their easy sharing and visualization. In particular, this research tested a 3D models optimization, a process which aims at the generation of Low Polygons models, with very low byte file size, processed starting from the data of High Poly ones, that nevertheless offer a level of detail comparable to the original models. To do this, several tools borrowed from the game industry and game engine have been used. For this test, three case studies have been chosen, a modern sculpture of a contemporary Italian artist, a roman marble statue, preserved in the Civic Archaeological Museum of Torino, and the frieze of the Augustus arch preserved in the city of Susa (Piedmont- Italy). All the test cases have been surveyed by means of a close range photogrammetric acquisition and three high detailed 3D models have been generated by means of a Structure from Motion and image matching pipeline. On the final High Poly models generated, different optimization and decimation tools have been tested with the final aim to evaluate the quality of the information that can be extracted by the final optimized models, in comparison to those of the original High Polygon one. This study showed how tools borrowed from the Computer Graphic offer great potentialities also in the Cultural Heritage field. This application, in fact, may meet the needs of multipurpose and multiscale studies, using different levels of optimization, and this procedure could be applied to different kind of objects, with a variety of different sizes and shapes, also on multiscale and multisensor data, such as buildings, architectural complexes, data from UAV surveys and so on

Algorithms for the reconstruction, analysis, repairing and enhancement of 3D urban models from multiple data sources

Over the last few years, there has been a notorious growth in the field of digitization of 3D buildings and urban environments. The substantial improvement of both scanning hardware and reconstruction algorithms has led to the development of representations of buildings and cities that can be remotely transmitted and inspected in real-time. Among the applications that implement these technologies are several GPS navigators and virtual globes such as Google Earth or the tools provided by the Institut Cartogràfic i Geològic de Catalunya. In particular, in this thesis, we conceptualize cities as a collection of individual buildings. Hence, we focus on the individual processing of one structure at a time, rather than on the larger-scale processing of urban environments. Nowadays, there is a wide diversity of digitization technologies, and the choice of the appropriate one is key for each particular application. Roughly, these techniques can be grouped around three main families: - Time-of-flight (terrestrial and aerial LiDAR). - Photogrammetry (street-level, satellite, and aerial imagery). - Human-edited vector data (cadastre and other map sources). Each of these has its advantages in terms of covered area, data quality, economic cost, and processing effort. Plane and car-mounted LiDAR devices are optimal for sweeping huge areas, but acquiring and calibrating such devices is not a trivial task. Moreover, the capturing process is done by scan lines, which need to be registered using GPS and inertial data. As an alternative, terrestrial LiDAR devices are more accessible but cover smaller areas, and their sampling strategy usually produces massive point clouds with over-represented plain regions. A more inexpensive option is street-level imagery. A dense set of images captured with a commodity camera can be fed to state-of-the-art multi-view stereo algorithms to produce realistic-enough reconstructions. One other advantage of this approach is capturing high-quality color data, whereas the geometric information is usually lacking. In this thesis, we analyze in-depth some of the shortcomings of these data-acquisition methods and propose new ways to overcome them. Mainly, we focus on the technologies that allow high-quality digitization of individual buildings. These are terrestrial LiDAR for geometric information and street-level imagery for color information. Our main goal is the processing and completion of detailed 3D urban representations. For this, we will work with multiple data sources and combine them when possible to produce models that can be inspected in real-time. Our research has focused on the following contributions: - Effective and feature-preserving simplification of massive point clouds. - Developing normal estimation algorithms explicitly designed for LiDAR data. - Low-stretch panoramic representation for point clouds. - Semantic analysis of street-level imagery for improved multi-view stereo reconstruction. - Color improvement through heuristic techniques and the registration of LiDAR and imagery data. - Efficient and faithful visualization of massive point clouds using image-based techniques.Durant els darrers anys, hi ha hagut un creixement notori en el camp de la digitalització d'edificis en 3D i entorns urbans. La millora substancial tant del maquinari d'escaneig com dels algorismes de reconstrucció ha portat al desenvolupament de representacions d'edificis i ciutats que es poden transmetre i inspeccionar remotament en temps real. Entre les aplicacions que implementen aquestes tecnologies hi ha diversos navegadors GPS i globus virtuals com Google Earth o les eines proporcionades per l'Institut Cartogràfic i Geològic de Catalunya. En particular, en aquesta tesi, conceptualitzem les ciutats com una col·lecció d'edificis individuals. Per tant, ens centrem en el processament individual d'una estructura a la vegada, en lloc del processament a gran escala d'entorns urbans. Avui en dia, hi ha una àmplia diversitat de tecnologies de digitalització i la selecció de l'adequada és clau per a cada aplicació particular. Aproximadament, aquestes tècniques es poden agrupar en tres famílies principals: - Temps de vol (LiDAR terrestre i aeri). - Fotogrametria (imatges a escala de carrer, de satèl·lit i aèries). - Dades vectorials editades per humans (cadastre i altres fonts de mapes). Cadascun d'ells presenta els seus avantatges en termes d'àrea coberta, qualitat de les dades, cost econòmic i esforç de processament. Els dispositius LiDAR muntats en avió i en cotxe són òptims per escombrar àrees enormes, però adquirir i calibrar aquests dispositius no és una tasca trivial. A més, el procés de captura es realitza mitjançant línies d'escaneig, que cal registrar mitjançant GPS i dades inercials. Com a alternativa, els dispositius terrestres de LiDAR són més accessibles, però cobreixen àrees més petites, i la seva estratègia de mostreig sol produir núvols de punts massius amb regions planes sobrerepresentades. Una opció més barata són les imatges a escala de carrer. Es pot fer servir un conjunt dens d'imatges capturades amb una càmera de qualitat mitjana per obtenir reconstruccions prou realistes mitjançant algorismes estèreo d'última generació per produir. Un altre avantatge d'aquest mètode és la captura de dades de color d'alta qualitat. Tanmateix, la informació geomètrica resultant sol ser de baixa qualitat. En aquesta tesi, analitzem en profunditat algunes de les mancances d'aquests mètodes d'adquisició de dades i proposem noves maneres de superar-les. Principalment, ens centrem en les tecnologies que permeten una digitalització d'alta qualitat d'edificis individuals. Es tracta de LiDAR terrestre per obtenir informació geomètrica i imatges a escala de carrer per obtenir informació sobre colors. El nostre objectiu principal és el processament i la millora de representacions urbanes 3D amb molt detall. Per a això, treballarem amb diverses fonts de dades i les combinarem quan sigui possible per produir models que es puguin inspeccionar en temps real. La nostra investigació s'ha centrat en les següents contribucions: - Simplificació eficaç de núvols de punts massius, preservant detalls d'alta resolució. - Desenvolupament d'algoritmes d'estimació normal dissenyats explícitament per a dades LiDAR. - Representació panoràmica de baixa distorsió per a núvols de punts. - Anàlisi semàntica d'imatges a escala de carrer per millorar la reconstrucció estèreo de façanes. - Millora del color mitjançant tècniques heurístiques i el registre de dades LiDAR i imatge. - Visualització eficient i fidel de núvols de punts massius mitjançant tècniques basades en imatges

Surface Appearance Estimation from Video Sequences

The realistic virtual reproduction of real world objects using Computer Graphics techniques requires the accurate acquisition and reconstruction of both 3D geometry and surface appearance. Unfortunately, in several application contexts, such as Cultural Heritage (CH), the reflectance acquisition can be very challenging due to the type of object to acquire and the digitization conditions. Although several methods have been proposed for the acquisition of object reflectance, some intrinsic limitations still make its acquisition a complex task for CH artworks: the use of specialized instruments (dome, special setup for camera and light source, etc.); the need of highly controlled acquisition environments, such as a dark room; the difficulty to extend to objects of arbitrary shape and size; the high level of expertise required to assess the quality of the acquisition. The Ph.D. thesis proposes novel solutions for the acquisition and the estimation of the surface appearance in fixed and uncontrolled lighting conditions with several degree of approximations (from a perceived near diffuse color to a SVBRDF), taking advantage of the main features that differentiate a video sequences from an unordered photos collections: the temporal coherence; the data redundancy; the easy of the acquisition, which allows acquisition of many views of the object in a short time. Finally, Reflectance Transformation Imaging (RTI) is an example of widely used technology for the acquisition of the surface appearance in the CH field, even if limited to single view Reflectance Fields of nearly flat objects. In this context, the thesis addresses also two important issues in RTI usage: how to provide better and more flexible virtual inspection capabilities with a set of operators that improve the perception of details, features and overall shape of the artwork; how to increase the possibility to disseminate this data and to support remote visual inspection of both scholar and ordinary public

Assessment of plastics in the National Trust: a case study at Mr Straw's House

The National Trust is a charity that cares for over 300 publically accessible historic buildings and their contents across England, Wales and Northern Ireland. There have been few previous studies on preservation of plastics within National Trust collections, which form a significant part of the more modern collections of objects. This paper describes the design of an assessment system which was successfully trialled at Mr Straws House, a National Trust property in Worksop, UK. This system can now be used for future plastic surveys at other National Trust properties. In addition, the survey gave valuable information about the state of the collection, demonstrating that the plastics that are deteriorating are those that are known to be vulnerable, namely cellulose nitrate/acetate, PVC and rubber. Verifying this knowledge of the most vulnerable plastics enables us to recommend to properties across National Trust that these types should be seen as a priority for correct storage and in-depth recording

Guidelines for the Management of Cultural Heritage Using 3D Models for the Insertion of Heterogeneous Data

[ES] La Gestión del Patrimonio Cultural (GPC) es una operación muy compleja cuyo objetivo es preservar la integridad física de los Bienes Culturales y, al mismo tiempo, difundir los valores históricos y permitir el disfrute del Patrimonio. Debido a las múltiples fases que componen la GPC (documentación, intervención, conservación preventiva, uso), el gestor se ve sometido a un gran esfuerzo de coordinación de las interacciones creadas por figuras profesionales muy diferentes, tanto por formación como por necesidades específicas en el ámbito de la gestión. En los últimos años, la aplicación de las tecnologías digitales al Patrimonio Cultural se ha convertido en una parte indispensable de la GPC. Las metodologías más utilizadas para la adquisición de datos, como el escaneo láser terrestre y la fotogrametría digital, también se han convertido en una práctica habitual en las actividades profesionales. Sin embargo, el uso de modelos 3D para la gestión se limita hasta ahora a algunas investigaciones académicas, que a menudo no tienen continuidad tras la finalización del proyecto. Además, hasta la fecha existen pocas normas supranacionales que guíen a las instituciones en el proceso de creación y uso de modelos 3D para la GPC. Por tanto, la falta de herramientas para controlar la calidad de los datos y productos digitales adquiridos afecta negativamente a la interacción entre el sector de la investigación académica, el sector de la gestión y el mundo profesional. La investigación propone el uso de los modelos 3D como una herramienta válida de apoyo en todas las fases de la gestión, ya sea utilizando los datos tridimensionales como base del archivo digital, o explotando todos los productos obtenidos a partir de los datos básicos para las múltiples acciones de cada fase. Por lo tanto, el objetivo de la tesis doctoral es desarrollar directrices para la producción de modelos 3D con el fin de gestionar, introducir y preservar eficazmente los datos. Estas directrices investigan todos los aspectos del proceso que va desde la adquisición de datos, pasando por su catalogación y archivo, hasta su tratamiento y la creación de un sistema de información simplificado para su gestión. Cada directriz guía al usuario a través de una fase específica del tratamiento y el uso de los datos digitales, y proporciona indicaciones adaptadas al nivel de conocimientos respecto a las tecnologías y metodologías digitales. De este modo, el gestor puede utilizar los modelos 3D para su gestión y controlar su calidad y sus estándares mínimos. Se ha optado por un enfoque interdisciplinar e internacional con el fin de elaborar directrices que se adapten al mayor número posible de Bienes Culturales, desarrollando la tesis en el marco de un acuerdo de cotutela entre la Universidad de Bolonia y la Universitat Politècnica de València. Con el fin de obtener unas pautas universales, las metodologías analizadas en el estudio del estado del arte se aplicaron a una serie de casos de estudio. Los principales son los monumentos paleocristianos de Rávena (Italia), pertenecientes a la Lista del Patrimonio Mundial de la UNESCO, y un panteón neogótico situado en Castellón de la Plana (España). Las experiencias realizadas sobre la GPC en los dos países han contribuido a la elaboración de directrices y normas universales que mejoren las interacciones entre el mundo académico, los gestores y el sector profesional. La investigación, al poner de manifiesto los problemas inherentes a la GPC, ha permitido identificar las principales cuestiones abiertas que se deben explorar en futuras líneas de investigación, como la aplicación de estándares a un gran número de Bienes Culturales para conducir a la puesta a punto de los mismos estándares; la búsqueda de sistemas para la clasificación automática de los datos brutos; el tratamiento de los datos recogidos para la creación de relaciones, estrategias y métodos de clasificación, integración y optimización de datos heterogéneos.[CA] La Gestió del Patrimoni Cultural (GPC) és una operació molt complexa l'objectiu de la qual és preservar la integritat física del els Béns Culturals i, al mateix temps, difondre els valors històrics i permetre el gaudi del Patrimoni. A causa de les múltiples fases que componen la GPC (documentació, intervenció, conservació preventiva, ús) , el gestor es veu sotmés a un gran esforç de coordinació de les interaccions creades per figures professionals molt diferents, tant per formació com per necessitats específiques en l'àmbit de la gestió. En els últims anys, l'aplicació de les tecnologies digitals al Patrimoni Cultural s'ha convertit en una part indispensable de la GPC, des de les fases de documentació fins a les d'intervenció. Les metodologies més utilitzades per a l'adquisició de dades, com l'escaneig làser terrestre i la fotogrametria digital, també s'han convertit en una pràctica habitual en les activitats professionals. No obstant això, l'ús de models 3D per a la gestió es limita fins ara a algunes investigacions i aplicacions acadèmiques, que sovint no tenen continuïtat després de la finalització del projecte. A més, fins a la data hi ha poques normes supranacionals que guien a les institucions en el procés de creació i ús de models 3D. Per tant, la falta de ferramentes per a controlar la qualitat de les dades i productes digitals adquirits afecta negativament la interacció entre el sector de la investigació acadèmica, el sector de la gestió i el món professional. La investigació proposa l'ús dels models 3D com una ferramenta vàlida de suport en totes les fases de la gestió, ja siga utilitzant les dades tridimensionals com a base de l'arxiu digital, o explotant tots els productes obtinguts a partir de les dades bàsiques per a les múltiples accions de cada fase. Per tant, l'objectiu de la tesi doctoral és desenrotllar directrius per a la producció de models 3D a fi de gestionar, introduir i preservar eficaçment les dades. Estes directrius investiguen tots els aspectes del procés que va des de l'adquisició de dades, passant per la seua catalogació i arxiu, fins al seu tractament i la creació d'un sistema d'informació simplificat per a la seua gestió. Cada directriu particular guia l'usuari a través d'una fase específica del tractament i l'ús de les dades digitals, i proporciona indicacions adaptades al nivell de coneixements respecte a les tecnologies i metodologies digitals. D'esta manera, el gestor pot utilitzar els models 3D per a la seua gestió i controlar la seua qualitat i els seus estàndards mínims. S'ha optat per un enfocament interdisciplinari i internacional a fi d'elaborar directrius que s'adapten al nombre més gran possible de tipus de Béns Culturals Cultural, desenrotllat la tesi en el marc d'un acord de cotutela entre la Universitat de Bolonya i la Universitat Politècnica de València. A fi d'obtindre unes pautes universals, les metodologies analitzades en l'estudi de l'estat de l'art es van aplicar a una sèrie de casos d'estudi. Els principals són els monuments paleocristians de Ravenna (Itàlia), pertanyents a la Llista del Patrimoni Mundial de la UNESCO, i una capella neogòtica situada a Castelló de la Plana (Espanya). Les experiències realitzades sobre la GPC en els dos països han contribuït a l'elaboració de directrius i normes universals que milloren les interaccions entre el món acadèmic, els gestors i el sector professional. La investigació, al posar de manifest els problemes inherents a la GPC, permet identificar les principals qüestions obertes que s'han d'explorar en futures línies d'investigació, com l'aplicació d'estàndards a un gran nombre de Béns Culturals per a conduir a la posada al punt dels mateixos estàndards; la busca de sistemes per a la classificació automàtica de les dades brutes; el tractament de les dades arreplegats per a la creació de relacions, estratègies i mètodes de classificació, integració i optimització de dades heterogènies.[EN] The Management of Cultural Heritage (MCH) is a very complex operation aimed at protecting the physical integrity of Cultural Heritage assets, while promoting their historical value and development of tourism industry. Composed by distinct phases (documentation, intervention, monitoring and use), MCH implies a great effort for the project manager to coordinate the interactions among very different professional figures. In recent years, the use of digital technologies has become an essential part of the MCH delicate process, from early documentation to late intervention phases. The most commonly used methodologies for digital data acquisition, such as terrestrial laser scanning and digital photogrammetry, have become common practice in a broad range of professional activities. On the contrary, the use of 3D models for MCH is still limited to few academic research to date, often lacking continuity and wide application after the end of specific projects. Furthermore, very few supra-national standard guidelines regulating their use are available to date. As a consequence, the operator who decides to use a 3D model as a basis for management is faced with the scarcity and fragmentation of standards and guidelines. Moreover, the lack of standard on quality of acquired data and digital products negatively influences the interaction between the academic research sector, the managers and the professional world. The focus is on the use of 3D models as a valid support tool in the MCH process, highlighting their advantages in all the distinct phases of the management. As an example, 3D data can constitute themselves the basis for the digital database, gathering all available information concerning a Cultural Heritage site, exploitable for restoration works or for scientific dissemination. In particular, the aim of this PhD research is to develop guidelines to produce 3D models for MCH, with the purpose to efficiently entry, store and manage digital data. The here provided guidelines investigate every aspect of the process leading from data acquisition to cataloguing and archiving, processing and creation of a simplified information system. Each recommendation guides the user through the management of digital data, by adapting to his/her level of knowledge with respect to digital technologies and methodologies. In this way, the manager can efficiently use 3D models in MCH projects. In order to elaborate guidelines that could be suitable for as many typologies of Cultural Heritage as possible an international approach was chosen, developing the thesis in joint supervision under the University of Bologna and the Universitat Politècnica de València. We decided to apply state-of-the-art technologies and methodologies to a variety of case studies. The main ones are the early Christian monuments of Ravenna (Italy) belonging to the UNESCO World Heritage List, and a small neogothic chapel located in Castellón de la Plana (Spain). The fruitful collaboration between two different countries allowed an invaluable exchange of MCH expertise and, more broadly, contributed to the elaboration of standardized and universally applicable MCH guidelines that will allow a better interaction between managers, the academic research world and the professional one. The investigation, by highlighting the problems inherent to the MCH, made it possible to identify the main open issues that need to be explored in future lines of research, such as the application of standards to a large number of cultural assets in an iterative, continuous and automatic way, in order to perfecting the standards; the search for automatic classification of raw data; the processing of collected data for the creation of relations, strategies and methods for the classification, integration and optimisation of heterogeneous data.Bertacchi, G. (2022). Guidelines for the Management of Cultural Heritage Using 3D Models for the Insertion of Heterogeneous Data [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/182419TESI

Metadata for phonograph records : facilitating new forms of use and access

This dissertation presents a new metadata design, as part of a large digitization management system being developed, to assist in the consistent creation of digital libraries of phonograph records. The Metadata provides digital libraries with an effective tool for the description, discovery, management, control, delivery, and sharing of digital objects of phonograph record. The metadata design is the outcome of two pilot projects for the digitization of phonograph records that took place at the Marvin Duchow Music Library at McGill University. The new design offers an approach to maintaining and using digital sound and ensures the long-term viability of digital libraries of phonograph records.The dissertation discusses key areas of preservation and addresses the most common retrieval problems of music in digital libraries. These problems include challenges in the digital context of bibliographic control, cataloging, distribution, and copyright protection. The dissertation revisits traditional cataloging approaches, summarizes historical music cataloging and metadata development, sets up preservation principles and rationales for digitizing phonograph records, and presents state-of-the-art techniques for preserving phonograph records in the digital domain.The dissertation contains three main parts. The first is an introduction to the new metadata design for phonograph records. The second is a metadata dictionary, which assigns precise syntactic and semantic meanings to metadata elements, to guide digitizers working in libraries, archives, museums, and heritage sectors. These will be followed by two case studies of phonograph record digitization projects using the Metadata and the Data Dictionary. The dissertation concludes by examining three challenges that are critical to future development in both the preserving of and access to phonograph records: the issue of interoperability between different metadata standards, the need for usability and quality evaluation of digitization management systems, and the importance of further development in digital library retrieval services and tools

Investigating the use of 3D digitisation for public facing applications in cultural heritage institutions

This thesis contains research into the use of 3D digitisation technologies by cultural heritage institutions in public facing applications. It is particularly interested in those technologies that can be adopted by institutions with limited budget and no previous experience in 3D digitisation. Whilst there has been research in the area of 3D imaging by museums and cultural heritage institutions, the majority is concerned with the use of the technology for academic or professional, curatorial purposes and on technical comparisons of the various technologies used for capture. Similarly, research conducted on the use of 3D models for public facing and public engagement applications has tended to focus on the various capture technologies, while little has been published on processing raw data for public facing applications – a time-consuming and potentially costly procedure. This research will investigate the issues encountered through the entire 3D digitisation workflow, from capture through processing to dissemination, focusing on the specific problems inherent in public facing projects and the heterogeneous and often problematic nature of museum objects. There has been little research published on the efficacy of 3D models both as providers of informational content and as public engagement tools used to fulfil a cultural heritage institution’s public facing remit. This research assesses the utility of interactive 3D models, as well as rendered animations of 3D content used as in-gallery exhibits and disseminated online. It finds that there is a prima facie case for believing that 3D models may be used to further a museum’s engagement and educational aims, and that there is an appetite among the general public for the use of this type of content in cultural heritage applications. The research will also compare a variety of methods for assessing the success of models

3D high resolution techniques applied on small and medium size objects: from the analysis of the process towards quality assessment

The need for metric data acquisition is an issue strictly related to the human capability of describing the world with rigorous and repeatable methods. From the invention of photography to the development of advanced computers, the metric data acquisition has been subjected to rapid mutation, and nowadays there exists a strict connection between metric data acquisition and image processing, Computer Vision and Artificial Intelligence. The sensor devices for the 3D model generation are various and characterized by different functioning principles. In this work, optical passive and active sensors are treated, focusing specifically on close-range photogrammetry, Time of Flight (ToF) sensors and Structured-light scanners (SLS). Starting from the functioning principles of the techniques and showing some issues related to them, the work highlights their potentialities, analyzing the fundamental and most critical steps of the process leading to the quality assessment of the data. Central themes are the instruments calibration, the acquisition plan and the interpretation of the final results. The capability of the acquisition techniques to satisfy unconventional requirements in the field of Cultural Heritage is also shown. The thesis starts with an overview about the history and developments of 3D metric data acquisition. Chapter 1 treats the Human Vision System and presents a complete overview of 3D sensing devices. Chapter 2 starts from the enunciation of the basic principle of close-range photogrammetry considering digital cameras functioning principles, calibration issues, and the process leading to the 3D mesh reconstruction. The case of multi-image acquisition is analyzed, deepening the quality assessment of the photogrammetric process through a case study. Chapter 3 is devoted to the range-based acquisition techniques, namely ToF laser scanners and SLSs. Lastly, Chapter 4 focuses on unconventional applications of the mentioned high-resolution acquisition techniques showing some examples of study cases in the field of Cultural Heritage

VR Technologies in Cultural Heritage

This open access book constitutes the refereed proceedings of the First International Conference on VR Technologies in Cultural Heritage, VRTCH 2018, held in Brasov, Romania in May 2018. The 13 revised full papers along with the 5 short papers presented were carefully reviewed and selected from 21 submissions. The papers of this volume are organized in topical sections on data acquisition and modelling, visualization methods / audio, sensors and actuators, data management, restoration and digitization, cultural tourism