GCH 2018 - Eurographics Workshop on Graphics and Cultural Heritage
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Browsing GCH 2018 - Eurographics Workshop on Graphics and Cultural Heritage by Subject "centered computing"
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Item 3D Reconstruction and Transparent Visualization of Indonesian Cultural Heritage from a Single Image(The Eurographics Association, 2018) Pan, Jiao; Li, Liang; Yamaguchi, Hiroshi; Hasegawa, Kyoko; Thufail, Fadjar I.; Mantara, Bra; Tanaka, Satoshi; Sablatnig, Robert and Wimmer, MichaelHerein, we propose a method for three-dimensional (3D) reconstruction of cultural heritage based on deep learning, which we apply to the reliefs of the Buddhist temple heritage of Borobudur Temple, in Indonesia. Some parts of the Borobudur reliefs have been hidden by stone walls and are not visible following the reinforcements during the Dutch rule. Today, only gray-scale photos of those hidden parts are displayed in the Borobudur Museum. First, we reconstruct 3D point clouds of the hidden reliefs from these photos and predict the pixel-wise depth information for each of them using a deep neural network model. We then apply our stochastic point-based rendering mechanism to produce a high-quality visualization of the reconstructed point clouds. We have achieved promising visualization results that provide us with an intuitive understanding of the valuable relief heritage that is no longer visible to ordinary visitors.Item Browsing Spatial Photography for Dissemination of Cultural Heritage Research Results using Augmented Models(The Eurographics Association, 2018) Niebling, Florian; Bruschke, Jonas; Latoschik, Marc Erich; Sablatnig, Robert and Wimmer, MichaelBoth digital and physical 3D models of buildings as well as historical photographs of architecture are used for a wide range of needs, from research in humanities and information technologies, museum contexts and library studies, to touristic applications. Spatially oriented photographs play an important role in visualizing and browsing contemporary as well as historical architecture, starting with the ground-breaking Photo Tourism project [SSS06]. We present a technique to combine physical, 3D-printed models of buildings with spatially registered historical photographic documents in a hand-held Augmented Reality (AR) environment. Users are enabled to spatially explore historical views of architecture by selecting photos from a collection of images, which are then utilized as textures for the physical model rendered on their respective mobile device. We compare different methods to spatially select photos registered to a physical model in hand-held AR.Item Data Visualization of Decoration Occurrence and Distribution. A Comparative Study of Late Egyptian Funerary Decoration in Thebes(The Eurographics Association, 2018) Wutte, Anja; Sablatnig, Robert and Wimmer, MichaelDecoration in Ancient Egyptian funerary monuments represents an important part of the monuments layout. Beside scenes displaying the owner, scenes of daily life, fabrication, offerings and hieroglyphic texts are found. Not only topics of self-presentation but also decoration for the translation to the afterlife were predominant. Therefore, this paper suggests approaches to analyze distribution and occurrence of decorations of several ancient monuments of the same style, with data visualization and quantitative methods. As a case study ancient Egyptian funerary monuments of High Officials from the Late Period, twenty-fifth to twenty-sixth dynasty, were studied. The decorative scenes were categorized and tagged in terms of their content. The positions in the monument were highlighted and included in abstracted 3-dimensional models. This computational implementation offers users to search for decoration categories, highlight, locate and finally compare the position of a scene between the monuments. The visualized data include the position and orientation of a categorized scene in the monument, their occurrence and distribution among the analyzed monuments. In a further step the analysis data was studied statistically in order to be able to query detailed results of the prevalence, distribution and preservation of decorations and specific scenes. Both introduced solutions provide a user friendly information interface to visualize, compare and request quantitative data.Item Evaluation of Multi-Platform Mobile AR Frameworks for Roman Mosaic Augmentation(The Eurographics Association, 2018) Cardoso, Jorge C. S.; Belo, André; Sablatnig, Robert and Wimmer, MichaelAugmented Reality (AR) development frameworks have different recognition performance on different kinds of target images. In this work, we studied AR frameworks applied in the context of outdoor Roman mosaic ruins with the final aim of developing a multi-platform mobile AR application. We started by analysing the documented features of existing frameworks to determine the feasible ones. This resulted in the selection of three frameworks: CraftAR, PixLive, and Wikitude. We then experimentally evaluated the performance of the target recognition features against real mosaics by measuring the recognition delay, minimum required target area, visual alignment and visual stability. Results indicate a good recognition rate for CraftAR and a poor recognition rate for Wikitude. CraftAR showed better recognition delay and visual stability, while PixLive showed better minimum required target area and visual alignment.Item Integrated Spatio-temporal Documentation and Analysis of Archaeological Stratifications Using the Harris Matrix(The Eurographics Association, 2018) Neubauer, Wolfgang; Traxler, Christoph; Lenzhofer, Andreas; Kucera, Matthias; Sablatnig, Robert and Wimmer, MichaelThe Harris Matrix (HM) is the fundamental diagrammatic representation of relative time for an archaeological site and the de facto standard for the representation of a stratigraphic sequence - the backbone for archaeological stratigraphy. It displays all uniquely identified units of stratification in a sequential diagram representing their relative temporal succession. The Harris Matrix Composer is a widely used application in the archaeological community to efficiently create and analyse HMs. However, it does not support explicit dating of HM units, which is an important information for post-excavation investigations of an archaeological site. In this paper we describe an integrated approach for a combination of stratigraphic and chronologic relations. The implicit, chronologic sequence given by the HM becomes explicit as scientists are enabled to define a hierarchical time model and assign units of the HM to temporal intervals or provide exact dating. The system maintains a consistent visual representation, which means that a correct stratigraphic layout is preserved while units are aligned to intervals of the time model. Evaluation of a real-world use case showed that this combined visualisation makes the scientific analysis and interpretation more efficient and reliable.Item Integrated Volume Visualisation of Archaeological Ground Penetrating Radar Data(The Eurographics Association, 2018) Bornik, Alexander; Wallner, Mario; Hinterleitner, Alois; Verhoeven, Geert; Neubauer, Wolfgang; Sablatnig, Robert and Wimmer, MichaelThe non-invasive prospection of our archaeological heritage is one of the main tasks of modern archaeology and often provides the necessary bases for further activities, such as special protection or intensified research. Geophysical prospections using ground-penetrating radar (GPR) are an invaluable tool for the non-destructive exploration of archaeological monuments still buried in the ground. However, the analysis and interpretation of the data sets generated in this way is a time-consuming and complex process and requires not only three-dimensional imagination but also a broad understanding of the archaeological remains. Therefore, understandable 3D visualisations are in great demand. This paper presents a novel integrated visualisation approach, which supports conjoint visualisation of scenes composed of heterogeneous data including GPR volumes and 3D models of interpretations and reconstructions. Visual depiction of relevant dataset areas and archaeological structures is facilitated based on flexible and localised visualisation techniques. Furthermore, the rendering system supports the computation of dynamic label layouts for scenes annotations.Item Objective and Subjective Evaluation of Virtual Relighting from Reflectance Transformation Imaging Data(The Eurographics Association, 2018) Pintus, Ruggero; Dulecha, Tinsae; Jaspe, Alberto; Giachetti, Andrea; Ciortan, Irina; Gobbetti, Enrico; Sablatnig, Robert and Wimmer, MichaelReflectance Transformation Imaging (RTI) is widely used to produce relightable models from multi-light image collections. These models are used for a variety of tasks in the Cultural Heritage field. In this work, we carry out an objective and subjective evaluation of RTI data visualization. We start from the acquisition of a series of objects with different geometry and appearance characteristics using a common dome-based configuration. We then transform the acquired data into relightable representations using different approaches: PTM, HSH, and RBF. We then perform an objective error estimation by comparing ground truth images with relighted ones in a leave-one-out framework using PSNR and SSIM error metrics. Moreover, we carry out a subjective investigation through perceptual experiments involving end users with a variety of backgrounds. Objective and subjective tests are shown to behave consistently, and significant differences are found between the various methods. While the proposed analysis has been performed on three common and state-of-the-art RTI visualization methods, our approach is general enough to be extended and applied in the future to new developed multi-light processing pipelines and rendering solutions, to assess their numerical precision and accuracy, and their perceptual visual quality.Item Proxy Painting(The Eurographics Association, 2018) Lange, Vanessa; Kurth, Philipp; Keinert, Benjamin; Boss, Martin; Stamminger, Marc; Bauer, Frank; Sablatnig, Robert and Wimmer, MichaelFor archaeologists it is often desireable to present statues in their original coloration. With projection mapping real-world surfaces are augmented by digital content to create compelling alterations of the scene's visual appearance without actually altering or even damaging the object. While there are frequent advances in projection quality, content creation is still a chal- lenging and often unintuitive task, especially for non-experts. In our presented system we combine the advantages of digital content creation such as rapid prototyping with the convenience of an analog workflow. Users paint on smaller versions of the projection mapping target, employing real-world brushes and pencils, while the results are presented live on its large counter- part. We further demonstrate the integration of our system into a state-of-art game engine. By leveraging a powerful rendering and material workflow we make creating compelling materials and lighting situations an intuitive experience.Item A Social Platform to Support Citizens Reuse of Open 3D Visualisations: a Citizen Science Approach(The Eurographics Association, 2018) Donato, Renato De; Santo, Massimo De; Negro, Alberto; Pirozzi, Donato; Rizzolo, Diletta; Santangelo, Gianluca; Scarano, Vittorio; Sablatnig, Robert and Wimmer, MichaelThere is a growing interest in the world of Open Data, with many initiatives in the Cultural Heritage field. Platforms like Europeana, archive.org, Open Heritage by Google are only few examples of on-line catalogues full of open artefacts published with various formats. It is a new and promising way to engage public, such as, students, citizens, non-profit organisations. This paper faces the question of how to help audience in reusing Open 3D models and other artefacts available on Open Cultural Heritage repositories. The idea is to provide a Social Platform named SPOD where citizens can visualise artefacts, share and comment with others in a social way to increase understanding, awareness and engagement in cultural heritage. The foundation is the Datalet-Ecosystem Provider (DEEP), an open source, extensible, scalable, and Edge-centric visualisation architecture to support reuse of visualisations of Open Data in Cultural Heritage. It consists of reusable, dynamic and interactive visualizations named datalets. It includes a variety of visualisations, charts, geographical maps and 3D visualisations. Datalets can be generated and embedded in any web-page as well. SPOD exploits the DEEP architecture to support users within the platform in generating visualisations of Open artefacts, reuse and share them within discussions.Item Visualising Dudsbury Hillfort: Using Immersive Virtual Reality to Engage the Public with Cultural Heritage(The Eurographics Association, 2018) John, David; Hurst, David; Cheetham, Paul; Manley, Harry; Sablatnig, Robert and Wimmer, MichaelWhilst computer visualisation is an established method of presenting cultural heritage, the use of game engines to provide a full immersive virtual reality experience is less well developed. This research documents the development of a visualisation of an Iron Age hillfort using Unreal Engine together with LiDAR terrain data to create a fully immersive experience for the virtual visitor. The visualisation was evaluated by 36 members of the public. The results show a high degree of satisfaction with the visualisation and agreement with the results of other studies demonstrating significant differences between those new to and those familiar with virtual reality applications. The conclusion is that in combination, game engines and LiDAR are effective tools for creating engaging virtual heritage visualisations.Item Visualization of Orientations of Spatial Historical Photographs(The Eurographics Association, 2018) Bruschke, Jonas; Niebling, Florian; Wacker, Markus; Sablatnig, Robert and Wimmer, MichaelHistorical imagery are an important basis for research in Digital Humanities (DH). Especially art and architectural historians rely on historical photographs that are provided by online media repositories. In general, querying those image repositories is based on metadata. Unfortunately, these are often incomplete, imprecise, or wrong, impeding the search process. Using photogrammetric methods to spatialize the historical imagery, keyword-based search is enhanced by time- and location-dependent browsing methods within a four-dimensional model. The interactive, spatial presentation and exploration of these images opens up new potentials to answer research questions related to art and architectural historical science. One important aspect of the work presented here is to provide visualization methods that present statistical information about image positions, and in particular camera orientations. In addition to heat maps, we present adaptations of methods from flow field visualization to enable the exploration of camera orientations in large numbers of photographic images.Item Visualizing Networks of Maya Glyphs by Clustering Subglyphs(The Eurographics Association, 2018) Bogacz, Bartosz; Feldmann, Felix; Prager, Christian; Mara, Hubert; Sablatnig, Robert and Wimmer, MichaelDeciphering the Maya writing is an ongoing process that has already started in the early 19th century. Among the reasons why Maya hieroglyphic script and language are still undeciphered are inexpertly-created drawings of Maya writing systems resulting in a large number of misinterpretations concerning the contents of these glyphs. As a consequence, the decipherment of Maya writing systems has experienced several setbacks. Modern research in the domain of cultural heritage requires a maximum amount of precision in capturing and analyzing artifacts so that scholars can work on - preferably - unmodified data as much as possible. This work presents an approach to visualize similar Maya glyphs and parts thereof and enable discovering novel connections between glyphs based on a machine learning pipeline. The algorithm is demonstrated on 3D scans from sculptured monuments, which have been filtered using a Multiscale Integral Invariant Filter (MSII) and then projected as a 2D image. Maya glyphs are segmented from 2D images using projection profiles to generate a grid of columns and rows. Then, the glyphs themselves are segmented using the random walker approach, where background and foreground is separated based on the surface curvature of the original 3D surface. The retrieved subglyphs are first clustered by their sizes into a set of common sizes. For each glyph a feature vector based on Histogram of Gradients (HOG) is computed and used for a subsequent hierarchical clustering. The resultant clusters of glyph parts are used to discover and visualize connections between glyphs using a force directed network layout.Item VR-assisted Architectural Design in a Heritage Site: the Sagrada Família Case Study(The Eurographics Association, 2018) Andujar, Carlos; Brunet, Pere; Buxareu, Jerónimo; Fons, Joan; Laguarda, Narcís; Pascual, Jordi; Pelechano, Nuria; Sablatnig, Robert and Wimmer, MichaelVirtual Reality (VR) simulations have long been proposed to allow users to explore both yet-to-built buildings in architectural design, and ancient, remote or disappeared buildings in cultural heritage. In this paper we describe an on-going VR project on an UNESCO World Heritage Site that simultaneously addresses both scenarios: supporting architects in the task of designing the remaining parts of a large unfinished building, and simulating existing parts that define the environment that new designs must conform to. The main challenge for the team of architects is to advance towards the project completion being faithful to the original Gaudí's project, since many plans, drawings and plaster models were lost. We analyze the main requirements for collaborative architectural design in such a unique scenario, describe the main technical challenges, and discuss the lessons learned after one year of use of the system.