Escaneado de artefactos religiosos con un escáner de luz estructurada

[EN] The digitization process for religious artifacts is subject to inherent difficulties often ignored in theoretical models or pipelines. In this paper we aim to describe these problems, which are present in practical environments such as temples and churches, using white light scanners instead of other common devices or technologies such as laser scanners and photogrammetry. Our case study is based on the digitization of two religious statues belonging to a Catholic brotherhood located in a village of the Province of Jaén (Spain), one of them presenting especially several limitations. After performing the scanning process with a portable hand-held scanner, the images captured were processed until the final models were acquired. On the basis of the results obtained, we discuss the problems arising after using well-known procedures for the reconstruction of 3D models, their causes and some possible solutions to achieving a correct digitization. It should be noted that it is not the aim of this study to establish procedures for the digitization of religious artifacts, but rather to transmit the inherent constraints of these types of scenes.[ES] Los modelos teóricos de digitalización 3D no tienen en cuenta problemas de escenarios específicos como el de la digitalización de objetos religiosos. El objetivo de este artículo es describir estos problemas presentes en entornos prácticos como templos o iglesias usando un escáner de luz blanca en lugar de otros instrumentos o tecnologías comunes como los escáneres láser y la fotogrametría. Nuestro caso de estudio se basa en la digitalización de dos tallas religiosas pertenecientes a una cofradía de una localidad de la provincia de Jaén (España), siendo especialmente restrictiva una de ellas. Tras el procedimiento de escaneado llevado a cabo con un escáner de mano, las capturas se procesaron usando procedimientos clásicos de reconstrucción de modelos 3D hasta obtener los resultados finales. Basándonos en los resultados obtenidos realizamos una discusión de los problemas, causas y posibles soluciones para llevar a cabo una correcta digitalización. Cabe destacar que el objetivo del artículo más que establecer un flujo de trabajo es el de presentar las restricciones que presentan este tipo de entornos.This study has been partially supported by the Ministerio de Ciencia e Innovación and the European Union (via ERDF funds) under the research project TIN2014-58218-R, and by the University of Jaén through the research project UJA2015/08/10Graciano, A.; Ortega, L.; Segura, RJ.; Feito, FR. (2017). Digitization of religious artifacts with a structured light scanner. Virtual Archaeology Review. 8(17):49-55. doi:10.4995/var.2016.4650SWORD4955817Wang, K., Lavoué, G., Denis, F., & Baskurt, A. (2011). Robust and blind mesh watermarking based on volume moments. Computers & Graphics, 35(1), 1-19. doi:10.1016/j.cag.2010.09.01

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

Batten Down the Hatches! Digitizing and Displaying Finds from the Spanish Plate Fleet Wrecks

Artefacts from the Spanish Plate Fleet Wrecks of 1715 and 1733 provide an unmatched archaeological window into 18th century life. To publicize these important finds that are often overshadowed by the wrecks’ alluring gold and silver treasures, the Florida Bureau of Archaeological Research Collections and Conservation section created an online 3D museum of selected artefacts. This presents our experiences as we plunged headfirst into the world of 3D photogrammetry and online museum development. We highlight our successes and failures with photogrammetry techniques, model creation, general workflow, and 3D web design for education and public outreach

Fuentes de color mejoradas para el modelado tridimensional de artefactos arqueológicos de tamaño medio localizados in situ.

[EN] The paper describes a color enhanced processing system - applied as case study on an artifact of the Pompeii archaeological area - developed in order to enhance different techniques for reality-based 3D models construction and visualization of archaeological artifacts. This processing allows rendering reflectance properties with perceptual fidelity on a consumer display and presents two main improvements over existing techniques: a. the color definition of the archaeological artifacts; b. the comparison between the range-based and photogrammetry-based pipelines to understand the limits of use and suitability to specific objects.[ES] El documento describe un sistema mejorado de procesamiento de color, aplicado como caso de estudio sobre un artefacto de la zona arqueológica de Pompeya. Este sistema se ha desarrollado con la finalidad de mejorar las diferentes técnicas para la construcción de modelos 3D basados sobre datos de la realidad y para la visualización de artefactos arqueológicos. Este proceso permite visualizar las propiedades de reflectancia con fidelidad perceptible en una pantalla de usuario y presenta dos mejoras principales respecto a las técnicas existentes:a. la definición del color de los artefactos arqueológicos;b. la comparación entre los flujos de trabajo basados en range-based-modeling y en fotogrametría, para entender los límites de uso y la adecuación a los objetos específicos.Apollonio, FI.; Ballabeni, M.; Gaiani, M. (2014). Color enhanced pipelines for reality-based 3D modeling of on site medium sized archeological artifacts. Virtual Archaeology Review. 5(10):59-76. https://doi.org/10.4995/var.2014.4218OJS5976510AGISOFT PHOTOSCAN (2014), http://www.agisoft.ru.ALLEN P., FEINER S., et al. 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(eds), Recording, Modeling and Visualization of Cultural Heritage, Taylor & Francis.BOOCHS F., BENTKOWSKA-KAFEL A., et al. (2013): "Towards optimal spectral and spatial documentation of Cultural Heritage. COSCH - an interdisciplinary action in the COST framework", in ISPRS Arch., Vol. XL-5/W2, 2013, pp. 109-113.CALLIERI M., CIGNONI P., et al. (2008): "Masked photo blending: mapping dense photographic dataset on high-resolution 3D models", in Computer & Graphics, Vol. 32, N. 4, 2008, pp. 464 - 473.CALLIERI M., DELLEPIANE M., et al. (2011): "Processing Sampled 3D Data: Reconstruction and Visualization Technologies", in F. Stanco, S. Battiato, G. Gallo (eds.), Digital Imaging for Cultural Heritage Preservation: Analysis, Restoration and Reconstruction of Ancient Artworks, Taylor and Francis, pp. 105-136.CORSINI M., DELLEPIANE M., et al. 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(2010): "Issues in Acquiring, Processing and Visualizing Large and Detailed 3D Models", in Information Sciences and Systems (CISS), 44th Annual Conference on, pp.1-6. http://dx.doi.org/10.1109/ciss.2010.5464966GONIZZI BARSANTI S., MICOLI L.L., GUIDI G. (2013a): "Quick textured mesh generation for massive 3D digitization of museum artifacts", in DigitalHeritage 2013, Vol. 1, pp. 197-200.GONIZZI BARSANTI S., REMONDINO F., VISINTINI D. (2013b): "3D surveying and modeling of archaeological sites - some critical issues", in ISPRS Ann. Photogramm. Remote Sens., Vol. II-5/W1, 2013, pp. 145-150.GRUSSENMEYER P., LANDES T., et al. (2008): "Comparison methods of terrestrial laser scanning, photogrammetry and tacheometry data for recording of cultural heritage buildings", in ISPRS Arch. Photogramm. Remote Sens., Vol. XXXVII/W5, pp. 213-218.GUARNIERI A., REMONDINO F., VETTORE A. 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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

Virtual Cultural Heritage: Virtual Reality Navigation of Cultural Heritage Environments

With the plethora of digital devices that can provide information about almost anything anywhere the Virtual Cultural Heritage project implements a prototype for the integration of personal computers and o the shelf new media accessories functioning in concert in order to deliver cultural heritage information. The virtual experience is navigated through the use of Microsoft Kinect motion control technology, integrating both gesture recognition and full body control, giving an element of realism and control previously not available in VR simulations. The interactive VR environment explores the possibilities of Le Musee Imaginaire, or the Museum Without Walls. The short-term goal is to draw upon scholarly research in areas of history and archaeological interpretation in order to distribute that knowledge to a general public in a non-traditional, engaging and entertaining manner. The long-range goal is to develop collaborative interdisciplinary projects that explore developing technologies and their new media applications in matters of cultural heritage, education and tourism.M.S., Digital Media -- Drexel University, 201

Visions of Substance: 3D Imaging in Mediterranean Archaeology

With the advent of low-cost and easy to use 3D imaging tools, the discipline of archaeology is on the cusp of a major change in how we document, study, and publish archaeological contexts. While there are a growing number of volumes dedicated to this subject, Visions of Substance: 3D Imaging in Mediterranean Archaeology represents an accessible and conversational introduction to the theory and practice of 3D imaging techniques in a Mediterranean and European context