GCH 2018 - Eurographics Workshop on Graphics and Cultural Heritage

Permanent URI for this collection

https://diglib.eg.org/handle/10.2312/2632673

Browse

Now showing 1 - 20 of 40

An Investigation of Optimal Light Source Setups for Photometric Stereo Reconstruction of Historical Coins
(The Eurographics Association, 2018) Brenner, Simon; Zambanini, Sebastian; Sablatnig, Robert; Sablatnig, Robert and Wimmer, Michael
In this paper, we address the 3D reconstruction of historical coins by means of Photometric Stereo. We investigate the influence of the number and arrangement of lights to the reconstruction quality by comparing mean angular errors on 22 historical coin models. Our results demonstrate that 6 lights circularly placed at an optimal elevation angle do not show a significant loss of reconstruction quality compared to a full semispherical dome setup with 54 lights. This represents a considerable saving of acquisition time and system complexity when it comes to the mass digitization of historical coins.
A Configurable Design Approach for Virtual Museums
(The Eurographics Association, 2018) Tsita, Christina; Sinanis, Anastasis; Dimitriou, Nikolaos; Papachristou, Kostas; Karageorgopoulou, Anastasia; Drosou, Anastasios; Tzovaras, Dimitrios; Sablatnig, Robert and Wimmer, Michael
Virtual Museums (VM) are widely used to preserve and to disseminate cultural heritage to the audience, due to the existing evidence that they can enhance the interest on cultural heritage content, while reinforcing motivation for a real museum visit. A variety of technologies are being used including Virtual Reality (VR), to display cultural heritage objects (CHOs) and related information, in order to offer enjoyable and immersive experiences to the visitors. Additionally, educational aspects of VMs are being explored, due to their inheritance from physical museums, which are educational institutions, among their other roles. Innovative approaches such as authoring tools for the creation of VMs have been introduced in order to fulfil the variant needs of field specialist, audience and educators. The diversity of contexts where a VM can be used, require the creation of open access tools to form customizable VMs for every need. This study aims to present a configurable design approach for the creation of VR museums. The goal is to disseminate the virtual artefacts and introduce them in an appealing way to the audience, the field experts and conservators, through VR experiences. The current version of the VM, allows the curators to dynamically insert objects in the virtual space along with their metadata and measurements derived from various scanning processes. The proposed design approach can support the structure of an open access platform for the creation of immersive VM exhibitions.
CultArc3D_mini: Fully Automatic Zero-Button 3D Replicator
(The Eurographics Association, 2018) Ritz, Martin; Knuth, Martin; Santos, Pedro; Fellner, Dieter W.; Sablatnig, Robert and Wimmer, Michael
3D scanning and 3D printing are two rapidly evolving domains, both generating results with a huge and growing spectrum of applications. Especially in Cultural Heritage, a massive and increasing amount of objects awaits digitization for various purposes, one of them being replication. Yet, current approaches to optical 3D digitization are semi-automatic at best and require great user effort whenever high quality is desired. With our solution we provide the missing link between both domains, and present a fully automatic 3D object replicator which does not require user interaction. The system consists of our photogrammetric 3D scanner CultArc3D_mini that captures an optimal image set for 3D geometry and texture reconstruction and even optical material properties of objects in only minutes, a conveyor system for automatic object feed-in and -out, a 3D printer, and our sensor-based process flow software that handles every single process step of the complex sequence from image acquisition, sensor-based object transportation, 3D reconstruction involving different kinds of calibrations, to 3D printing of the resulting virtual replica immediately after 3D reconstruction. Typically, one-button machines require the user to start the process by interacting over a user interface. Since positioning and pickup of objects is automatically registered, the only thing left for the user to do is placing an object at the entry and retrieving it from the exit after scanning. Shortly after, the 3D replica can be picked up from the 3D printer. Technically, we created a zero-button 3D replicator that provides high throughput digitization in 3D, requiring only minutes per object, and it is publicly showcased in action at 3IT Berlin.
Virtual Reality (VR) Interactions With Multiple Interpretations of Archaeological Artefacts
(The Eurographics Association, 2018) Gaugne, Ronan; Samaroudi, Myrsini; Nicolas, Théophane; Barreau, Jean-Baptiste; Garnier, Laurent; Echavarria, Karina Rodriguez; Gouranton, Valérie; Sablatnig, Robert and Wimmer, Michael
Increasingly, the incorporation of 3D printed artefacts into Virtual Reality (VR) and Augmented Reality (AR) experiences is of interest to Cultural Heritage professionals. This is because virtual environments, by themselves, cannot convey information such as the physical properties of artefacts within the environments. This paper presents a methodology for the development of VR experiences which incorporate 3D replicas of artefacts as user interfaces. The methodology is applied on the development of an experience to present various interpretations of an urn which was found at the edge of a cliff on the south east coastal area of the United Kingdom in 1910. In order to support the understanding of the multiple interpretations of this artefact, the system deploys a virtual environment and a physical replica to allow users to interact with the artefacts and the environment. Feedback from heritage users suggests VR technologies along with digitally fabricated replicas can meaningfully engage audiences with multiple interpretations of cultural heritage artefacts.
Participatory Co-creation of a Public Sculpture Incorporating 3D Digital Technologies
(The Eurographics Association, 2018) Echavarria, Karina Rodriguez; Janzon, Karin; Wright, Jonathan; Sablatnig, Robert and Wimmer, Michael
This paper presents a interdisciplinary project between artists, civic groups, heritage organisations, technical experts and communities to co-create a piece of artwork for the community. Constellation is the name of the sculpture, and Jonathan Wright, its creator, used a co-creation approach to develop both the design and fabrication of the artwork. To be installed in the Hove Plinth in Brighton & Hove (UK) and commissioned by the Hove Civic Society, this sculpture was envisaged as a celebration of the community's heritage. As such, the mechanical model was designed as a solar system and instead of planets, the most iconic heritage objects in the city were selected to orbit the system. In collaboration with communities, the artist selected these icons which were later 3D scanned in collaboration with technical experts and local heritage organisations. The icons were then manufactured using digital fabrication technologies, and installed in the sculpture. The inauguration of Constellation took place in April 2018 with very good reception from the public. Hence, this paper illustrates the advantages of co-creative approaches which incorporate digital technologies into their workflow.
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, Michael
Both 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.
Granitic Recumbent Statue Reproduction by a Seven Axes Robotic Milling Machine
(The Eurographics Association, 2018) Barreau, Jean-Baptiste; Jouneau, Joëlle; Mérelle, Johnny; Maillard, Loïc; Bernard, Yann; Quesnel, Laurent; Sablatnig, Robert and Wimmer, Michael
Facing the sea, the rocks sculpted by the "Abbé Fouré" at the "Pointe du Christ" and the "Pointe de la Haie" in Rothéneuf (Brittany, France) attract many visitors. Winds, rains and sea spray erode each day a little more the sculptures carved in granite more than a century ago. In order to preserve the heritage, the "Association des Amis de l'Oeuvre de l'Abbé Fouré" tried to start an innovative project: recreate a statue sculpted by the "Ermite of Rothéneuf" at the end of the 19th century thanks to 3D technologies and robotics. With a first 3D scanning of the sculpture of the "Pointe du Christ", a stonecutters' company was approached to reproduce identically this recumbent statue, identified as John IV, Duke of Brittany. Thanks to a robotic milling machine working on seven axes, by cutting layers in the granite at each passage, the company realized 60% of the work in less than a month. Then, a sculptor of the company was responsible, from documents collected by the association, to give the granite block the features of the original recumbent statue. This replica is currently the centerpiece of several French exhibitions dedicated to the general public.
Frontmatter: Eurographics Workshop on Graphics and Cultural Heritage
(The Eurographics Association, 2018) Sablatnig, Robert; Wimmer, Michael; Sablatnig, Robert and Wimmer, Michael
Visualizing Networks of Maya Glyphs by Clustering Subglyphs
(The Eurographics Association, 2018) Bogacz, Bartosz; Feldmann, Felix; Prager, Christian; Mara, Hubert; Sablatnig, Robert and Wimmer, Michael
Deciphering 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.
Development of a High Resolution Topography and Color Scanner to Capture Crack Patterns of Paintings
(The Eurographics Association, 2018) Hengstum, Mathijs J. W. van; Essers, Tessa T. W.; Elkhuizen, Willemijn S.; Dodou, Dimitra; Song, Yu; Geraedts, Jo M. P.; Dik, Joris; Sablatnig, Robert and Wimmer, Michael
The aging of paintings is inevitable and over the years degradation occurs due to exposure to a variety of environmental influences. One of these degradations is craquelure, fracture patterns in the paint. 3D imaging techniques offer opportunities to capture the surface of a painting and these patterns at high resolution. In this paper we present a 3D scanner that is able to capture surface topography and color of oil paintings at high resolution utilizing fringe-encoded stereo imaging scanning system. The scanner is capable of automated capture of an area of 1x1m2, capturing a painting at a spatial resolution of 7 micron and a depth accuracy of 34 microns. Scanning at this resolution creates potential research opportunities for documentation and monitoring oil paintings under its environmental influences. A scan was made of 'Girl with a Pearl Earring' (c.1665), painted by Johannes Vermeer, which exhibits fine craquelure patterns. The scanner is able to capture the painting of 39x44.5 cm within 2 hours with a tile overlap of 25%. The results showed that the craquelure has more often a ridge-shaped profile instead of the expected inward valleys. The documentation of these variations in crack profiles create interesting paths for future research.
Virtual Restoration of Wooden Artifacts by Non-Rigid 3D Shape Assembly: A Case of the First Solar Boat of King Khufu
(The Eurographics Association, 2018) Nemoto, Takashi; Kobayashi, Tetsuya; Oishi, Takeshi; Kagesawa, Masataka; Kurokochi, Hiromasa; Yoshimura, Sakuji; Ziddan, Eissa; Taha, Mamdouh; Sablatnig, Robert and Wimmer, Michael
In this paper, we present a method to digitally reassemble an object to its original form given the 3D data of its component which are assumed to be non-rigidly deformed. Targeting wooden artifacts, we developed an algorithm to deform the components parametrically, and constraints based on the physical properties of wood are imposed on the deformation. We apply our method to a deformed cultural asset, specifically the first solar boat of King Khufu which is made of wood.
Gloss Calibration and Gloss Gamut Mapping for Material Appearance Reproduction of Paintings
(The Eurographics Association, 2018) Elkhuizen, Willemijn S.; Essers, Tessa T. W.; Song, Yu; Pont, Sylvia C.; Geraedts, Jo M. P.; Dik, Joris; Sablatnig, Robert and Wimmer, Michael
Being able to link captured material characteristics and fabricable material appearance attributes is important for creating life-like reproductions. In this paper we propose a method for gloss calibration, and an approach for gloss gamut mapping, as part of an integrated approach for color, topography and gloss reproduction. For gloss calibration, gloss calibration targets were printed in the primary printing colors (CMYK and White), with uniform gloss in equal distant gloss levels. These targets were scanned using the proposed gloss scanner. To create the gloss gamut map, a monotonic curve was fitted to the mean gloss scan values at different gloss levels. Analysis of fitted curves indicated that the gloss mapping is independent of the diffuse colors. As a case study, the painting 'Fruit Still Life' by Cornelis de Heem was scanned, and the measured gloss was mapped to printable gloss levels using the relation described by the fitted curve. The printed result shows good correspondence to the painting's appearance, with clearly distinguishable gloss features for the in-gamut glass values.
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, Michael
Decoration 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.
Aging Prediction of Cultural Heritage Samples Based on Surface Microgeometry
(The Eurographics Association, 2018) Ciortan, Irina Mihaela; Marchioro, Giacomo; Daffara, Claudia; Pintus, Ruggero; Gobbetti, Enrico; Giachetti, Andrea; Sablatnig, Robert and Wimmer, Michael
A critical and challenging aspect for the study of Cultural Heritage (CH) assets is related to the characterization of the materials that compose them and to the variation of these materials with time. In this paper, we exploit a realistic dataset of artificially aged metallic samples treated with different coatings commonly used for artworks' protection in order to evaluate different approaches to extract material features from high-resolution depth maps. In particular, we estimated, on microprofilometric surface acquisitions of the samples, performed at different aging steps, standard roughness descriptors used in materials science as well as classical and recent image texture descriptors. We analyzed the ability of the features to discriminate different aging steps and performed supervised classification tests showing the feasibility of a texture-based aging analysis and the effectiveness of coatings in reducing the surfaces' change with time.
On Combining Epigraphy, TLS, Photogrammetry, and Interactive Media for Heritage Documentation: The Case Study of Djehutihotep's Tomb in Dayr al-Barsha
(The Eurographics Association, 2018) Lima, Roberto de; Sykora, Toon; Meyer, Marleen De; Willems, Harco; Vergauwen, Maarten; Sablatnig, Robert and Wimmer, Michael
The governors' tombs located at Dayr al-Barsha are considered among the most important monuments of the Egyptian Middle Kingdom. Unfortunately, due to quarrying activities, looting, and natural catastrophes, the archaeological remains are now in a dilapidated state. Their documentation therefore becomes a necessary task towards the preservation and research of this provincial elite cemetery. Traditional geomatics-based heritage recording methods and sensors are, however, not sufficient to yield a full and comprehensive documentation. Inspired by emergent technologies, this paper proposes a symbiosis of digital epigraphy, Terrestrial Laser Scanning (TLS), image-based digitalization techniques, and 3D visualization platforms, to provide experts with a digital tool able to yield high-level information in terms of accurate digital drawings of decorated sections and dense 3D mesh models. Results show that the proposed approach provides a reliable alternative to answer research questions, especially in the context of ancient Egyptian heritage, as the level of detail captured enables the academic community to further explore decoration techniques, damage recognition, and digital reconstruction.
New Haven Building Archive: A Database for the Collection, Study, and Communication of Local Built Heritage
(The Eurographics Association, 2018) Rubin, Elihu; Akhtar, Saima; Brown, Benedict; Rushmeier, Holly; Sablatnig, Robert and Wimmer, Michael
The New Haven Building Archive (NHBA) is a digital, mobile, and interactive field guide to New Haven, Connecticut's built heritage. As an interactive digital guide and database for local buildings, the NHBA harnesses digital mapping technologies, place-based storytelling and community-based research. Ultimately, the development of the NHBA will aid in the co-production of knowledge about the city by students, academic researchers and local citizens in a way that will facilitate conversations about the historical patterns and future development of New Haven while suggesting a model for engaged teaching and research for urban studies more broadly.
Multi-Light Energy Map
(The Eurographics Association, 2018) Lardeux, Florian; Marchand, Sylvain; Gomez-Krämer, Petra; Sablatnig, Robert and Wimmer, Michael
We propose a model to represent quasi-flat objects, such as coins or amphora stamps. These objects are flat surfaces, meaning their length and their width largely exceed their height, and feature a distinctive relief. This relief characterizes the object and its perception is directly influenced by the position of the object, the light direction and the viewer's direction. Our model is a single image representation containing the underlying structural variations of the object. This model, that we call 'Multi-Light Energy Map', is constructed out of several classic images taken with several illumination directions without computing the object's surface normals. We found a way to extract useful information out of this sequence of images and compile it into our map. We eventually explain how we can use this model in the case of image registration of ancient coins.
Deep Mapping Tarn Hows: Automated Generation of 3D Historic Landscapes
(The Eurographics Association, 2018) Reinhold, Alexander; Gregory, Ian; Rayson, Paul; Sablatnig, Robert and Wimmer, Michael
Changing landscape presents a problem for both conservation and education at heritage sites. We consider the site of Tarn Hows in the English Lake District National Park, a site which has had significant landscape change over the past 200 years, from developing tree coverage, to the merging of three lakes into one. We created an automated process that combines an elevation map and a vegetation map to build a 3D representation of the landscape. We used this tool to create a 3D Deep Map of Tarn Hows, representing the site's landscape at multiple periods over time, allowing them to be viewed side by side and explored in an interactive environment. This 3D Deep Map provides an exploratory resource for site authorities to educate the public about the historic environment, with embedded multimedia in the application to provide additional information to users that might be disruptive or impractical to display on site. The 3D Deep Map also provides a tool for conservators to plan site maintenance to best maintain the integrity of the historic landscape without negatively impacting visitors' experience of the iconic site.
Elastic Flattening of Painted Pottery Surfaces
(The Eurographics Association, 2018) Preiner, Reinhold; Karl, Stephan; Bayer, Paul; Schreck, Tobias; Sablatnig, Robert and Wimmer, Michael
Generating flat images from paintings on curved surfaces is an important task in Archaeological analysis of ancient pottery. It allows comparing styles and painting techniques, e.g, for style and workshop attribution, and serves as basis for domain publications which typically use 2d images. To obtain such flat images from scanned textured 3d models of the pottery objects, current practice is to perform so-called rollouts using approximating shape primitives like cones or spheres, onto which the mesh surfaces are projected. While this process provides in intuitive deformation metaphor for the users, it naturally introduces unwanted distortions in the mapping of the surface, especially for vessels with high-curvature profiles. In this work, we perform an elastic flattening of these projected meshes, where stretch energy is minimized by simulating a physical relaxation process on a damped elastic spring model. We propose an intuitive contraction-directed physical setup which allows for an efficient relaxation while ensuring a controlled convergence. Our work has shown to produce images of significantly improved suitability for domain experts' tasks like interpretation, documentation and attribution of ancient pottery.
An Image-based Approach for Detecting Faces Carved in Heritage Monuments
(The Eurographics Association, 2018) Lai, Yu-Kun; Echavarria, Karina Rodriguez; Song, Ran; Rosin, Paul L.; Sablatnig, Robert and Wimmer, Michael
Heritage monuments such as columns, memorials and buildings are typically carved with a variety of visual features, including figural content, illustrating scenes from battles or historical narratives. Understanding such visual features is of interest to heritage professionals as it can facilitate the study of such monuments and their conservation. However, this visual analysis can be challenging due to the large-scale size, the amount of carvings and difficulty of access to monuments across the world. This paper makes a contribution towards this goal by presenting work-in-progress for developing image-based approaches for detecting visual features in 3D models, in particular of human faces. The motivation for focusing on faces is the prominence of human figures throughout monuments in the world. The methods are tested on a 3D model of a section of the Trajan Column cast at the Victoria and Albert (V&A) Museum in London, UK. The initial results suggest that methods based on machine learning can provide useful tools for heritage professionals to deal with the large-scale challenges presented by such large monuments.

Browse

Browsing GCH 2018 - Eurographics Workshop on Graphics and Cultural Heritage by Issue Date

Results Per Page

Sort Options