DH2013 - Digital Heritage International Congress 2013

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Reverse Engineering of Scale Models Using Dataflow Programming: Application to the fortification of plans-reliefs
(The Eurographics Association, 2013) Jacquot, Kevin; Chevrier, Christine; Gilles, Halin; -
Despite the progress in three-dimensional scanning, some architectural artifacts remain a digitizing challenge. Scale models and more especially the plans-reliefs of Louis XIV of France have specific characteristics such as size, scale, number, etc. A knowledge-based modeling approach is developed to address the limitations of digitizing tools. Our study deals with the fortified areas of the scale models. Bastioned fortification works extend over wide areas but they are built according to design rules. Once studied and organized, fortification knowledge has been used to create a library of parametric components. Implemented in Grasshopper, the components were manually adjusted to different practical cases. The library was then validated and we are now focusing on the automation of the adjustments of the components. Thereupon a reverse-engineering approach has been set up. Semantic segmentation algorithms have been defined and implemented in Grasshopper to automatically extract fortification features from 3D surveys based on the knowledge of fortification design rules. Along with the three-dimensional modeling of fortification, an automatic reconstruction of the city parts of the scale models is underway. Both these studies are part of a project aimed at valorizing and diffusing a very unique cultural heritage collection. As such, knowledge models are precious assets both the digitizing and the semantic enhancements of the final application.
Seamless Texturing of Archaeological Data
(The Eurographics Association, 2013) Birsak, Michael; Musialski, Przemyslaw; Arikan, Murat; Wimmer, Michael; -
In this paper we propose a framework for out-of-core real-time rendering of high-quality textured archaeological data-sets. Our input is a triangle mesh and a set of calibrated and registered photographs. Our system performs the actual mapping of the photos to the mesh for high-quality reconstructions, which is a task referred to as the labeling problem. Another problem of such mappings are seams that arise on junctions between triangles that contain information from different photos. These are are approached with blending methods, referred to as leveling. We address both problems and introduce a novel labeling approach based on occlusion detection using depth maps that prevents texturing of parts of the model with images that do not contain the expected region. Moreover, we propose an improved approach for seam-leveling that penalizes too large values and helps to keep the resulting colors in a valid range. For highperformance visualization of the 3D models with a huge amount of textures, we make use of virtual texturing, and present an application that generates the needed texture atlas in significantly less time than existing scripts. Finally, we show how the mentioned components are integrated into a visualization application for digitized archaeological site.
Dense Image Matching: comparisons and analyses
(The Eurographics Association, 2013) Remondino, Fabio; Nocerino, Erica; Menna, Fabio; Nex, Francesco; Spera, Maria Grazia; Gonizzi-Barsanti, Sara; -
The paper presents a critical review and analysis of dense image matching algorithms. The analyzed algorithms stay in the commercial as well open-source domains. The employed datasets include scenes pictured in terrestrial and aerial blocks, acquired with convergent and parallel-axis images and different scales. Geometric analyses are reported, comparing the dense point clouds with ground truth data.
Placing Intangible Cultural Heritage
(The Eurographics Association, 2013) Karavia, Despoina; Georgopoulos, Andreas; -
Over the last decades, the concept of Cultural Heritage has included Intangible Cultural Heritage (ICH), mainly due to UNESCO's initiatives. ICH is in danger of disappearance or degradation due to globalization, immigration, urbanization etc. On the other hand, ICH is strongly related to the features of space. It is formed and developed in a specific location, which is influenced by the vicinity with other civilizations. Its topographic features (altitude, inclination, distance from sea or freshwater, climate etc.), their influence in everyday life and the natural raw materials present are determinant in the process of the ICH formation. It is very important to capture and analyze the various forms of ICH, in order to extract the latent human creativity hidden in them, while at the same time studying the influence of space on their evolution. Their capture should be done by implementing appropriate equipment, methods and archival formats in order to fully describe them and to ensure the preservation of the resulting digital archives. Nowadays, the evolution of technology provides flexible means towards this aim. Furthermore, Geographic Information Systems (GIS) are a tool to disseminate and manage spatial data and their relations to attributes, like the forms of ICH They allow the correlation of data, the response to spatial queries and they can lucidly visualize the data. On one hand, a web GIS system, can designate and preserve ICH by presenting the digital records of its forms and by focusing on its relations to place. On the other hand, such a system can be implemented on a research level, by introducing the analysis of the ICH forms, in order to study the influence of the geographic and topographic features of space on their evolution and formation and to study similarities and relationships between ICH of different communities and cultures. This paper describes an integrated approach to the issues of digitization of ICH and the implementation of the analysis- within a GIS environment. Its practical application requires large effort by a multidisciplinary scientific team.
Patterning Culture: Developing a system for the visual notation of greetings
(The Eurographics Association, 2013) Shortt, Marie Therese; -
My research explores how the human interaction of greeting can be analysed through a digital graphic visualisation process to reveal nonverbal dimensions such as personal space, touch and other movement patterns. Previous systems of visualization devised by anthropologists for the study of greetings have stopped short of using contemporary digital technology. I aim to show how the use of digital techniques such as stop motion video, vector animation and interactive programming in the documentation and analysis of human greetings can advance our understanding of culturally patterned behaviour. Such visual and interactive explanations of greetings also open up the possibility of historical preservation and mapping of cultural greetings and, potentially, other forms of human interaction.
3D Reconstruction of an outdoor archaeological site through a multi-view stereo technique
(The Eurographics Association, 2013) Muzzupappa, Maurizio; Gallo, Alessandro; Spadafora, Francesco; Manfredi, Felix; Bruno, Fabio; Marca, Antonio La; -
This paper describes the experimentation of a common multi-view stereo technique on a particularly complex test case: the ''Via Colonnata'' in the archaeological site of Kyme Eolica in Turkey. The study demonstrates that it is possible to create a detailed 3D model of an area sized tens of square meters without the need to use any dedicated device like laser scanners, drones or helium balloons, but just employing a digital camera and open source software. The reconstruction process implemented in this study addresses and solves some of the most relevant problems related to the reconstruction of large areas and the subsequent mapping of a texture on the geometrical model. In particular, we suggest some guidelines for the acquisition phase that help to reduce the subsequent problems related both to 3D geometry creation and texture mapping. In the pre-processing phase, we propose an automated technique for filtering of unimportant areas, based on the analysis of the disparity maps related to each image pair (the farther areas from the current point of view are masked out, in order to obtain a 3D model free of artifacts/defects). For the texture mapping process, in order to reduce the blur resulting from averaging and blending operations in overlapping areas, we propose a method that automatically identifies the most appropriate subset of images to be projected on the 3D model.
A Computer Simulation to Test the Buchner Thesis. The Relationship of the Ara Pacis and Meridian in the Campus Martius, Rome
(The Eurographics Association, 2013) Frischer, Bernard; Fillwalk, John; -
3D modeling was first introduced into the fields of archaeology and art history in the early 1990s as a new form of illustration derived from the traditional paper-based plan, section, and elevation. In recent years, it has become clear that once we have an accurate 3D restoration model of a lost or damaged cultural heritage monument, we can use the model to pose new questions and generate new discoveries and insights. This paper will consider this heuristic use of 3D models in the field of archaeoastronomy. A simulation of a built environment that includes an accurate solar tracker with historical azimuthal data drawn from NASA's Horizons System can allow us to test alignments hypothesized in the scholarly literature and to discover hitherto unsuspected alignments. We will report on our development of a Unity simulation of the northern part of the Campus Martius in Rome during the period 8 BCE to 40 CE. We made the simulation in order to test the validity of a thesis first proposed by Edmund Buchner in the 1970s according to which two Augustan monuments built in this part of the city were designed to have a solar alignment on Augustus' birthday: the so-called Horologium Augusti and the Ara Pacis. Since Buchner wrote, his thesis has been hotly debated by Roman topographers. A computer simulation may be able to move research on this topic beyond the current impasse.
Linking 3D Digital Surface Texture Data with Ancient Manufacturing Procedures
(The Eurographics Association, 2013) Almeida, Vera Moitinho de; Barceló, Juan Antonio; Rosillo, Rafel; Palomo, Antoni; -
Surface texture is a key parameter in archaeological materials, where its study has been central to use-wear research, as well as in the understanding of manufacturing processes. Nowadays, 3D digital surface textures can be characterized from macroscale to nanoscale, using advanced metrology methods and techniques, and by means of 2D profile or 3D areal (non-)contact instruments, which span a wide range and resolution. In this paper, we describe an experiment based on the quantitative description of geometric surface texture patterns (i.e., the microtopography) from 3D scanned archaeological and experimental materials, in order to assess how objects were manufactured in the past. At the end, we aim to differentiate texture patterns; associate them with possible gestures, carving techniques, and used tools; and understand the technical procedure used by the craftsperson. The archaeological object of study is a large fragment of one of the stelae with carved horns on blocks of sandstone, late 4th millennium cal BC, discovered in 2008 in the Neolithic settlement in the Serra del Mas Bonet (Vilafant, Alt Empordà), Catalonia. Experimental replicas of this fragment's surface textures were made in blocks of sandstone coming from the same bedrock. The applied method consisted of using a 3D structured light scanner, with a submillimetre resolution, to capture the geometric surface texture of both prehistoric and experimental objects. Then, using surface roughness areal parameters, regulated by international standards, to describe quantitatively the texture patterns of a set of sampled areas. After that, comparisons were made, and a first conclusion is here presented.
Web Visualization of Complex Reality-Based 3D Models with Nubes
(The Eurographics Association, 2013) Palacios, Belen Jimenez Fernandez; Stefani, Chiara; Lombardo, Julie; Luca, Livio de; Remondino, Fabio; -
This paper discusses the fundamental issues of the real-time web-based visualization of complex reality-based 3D models. As web platform, we use NUBES, an innovative and powerful tool for sharing and analyzing reality-based 3D models online. A new automatic procedure for the setting-up and the uploading of 3D complex scenes into NUBES is presented, including the optimization of the geometric and radiometric information for web visualization.
Living Heritage A living lab for digital content production focused on cultural heritage.
(The Eurographics Association, 2013) Felice, Giuliano De; -
Only linking the most advanced technical solutions with creativity and innovative languages it is possible to realize communication products and strategies that can respect and boost the expressive potential of archaeology, and win the big challenge of interpretation, reconstruction and communication. Living Heritage is a project carried out by several enterprises specialized in digital content industry, in collaboration with the Digital Archaeology Lab (LAD) of University of Foggia and Regional Directorate for cultural Heritage of Apulia. The project aims to tool up a living lab that will set up and test a collaborative production methodology of digital content for archaeology and cultural heritage among technologies, languages and creativity. The co-design approach will be tested as a solution to improve the quality of communication, reaching results that should be at the same time scientifically correct and attractive.
V-embodiment for Cultural Heritage
(The Eurographics Association, 2013) Flynn, Bernadette; -
The paper argues that there is a need to consider sentient engagement in the digital expressions of cultural heritage. Focusing on full body 'natural interaction' the presentation looks at strategies for a phenomenological framework through the design for an embodied motion-sensing environment and analysis of a particular case study of Neolithic era sites and artefacts. The exchange between virtuality and embodiment, immersion and performativity is examined in particular how movement and kinaesthetic engagement can enhance embodied presence and forms of somatic knowledge. Models are proposed that represent phenomenological value for an emergent somatic heritage.
An Interactive Visualization of the Past using a Situated Simulation Approach
(The Eurographics Association, 2013) Madsen, Jacob B.; Madsen, Claus B.; -
This paper describes aspects of the development of an interactive installation for visualizing a 3D reconstruction of a historical church chapel in Kolding, Denmark. We focus on three aspects inherent to a mobile Augmented Reality development context; 1) A procedure for combating gyroscope drift on handheld devices, 2) achieving realistic lighting computation on a mobile platform at interactive frame-rates and 3) an approach to relocation within this applications situated location without position tracking. We present a solution to each of these three aspects. The development is targeted a specific application, but the presented solutions should be relevant to researchers and developers facing similar issues in other contexts. We furthermore present initial findings from everyday usage by visitors at the museum, and explore how these findings can be useful in connection with novel technology for facilitating information transfer to a museum audience. The installation is in active commercial use and is currently logging further user interactions via in-application logging for future investigations in line with this project.
ATHENA: Automatic Text Height ExtractioN for the Analysis of old handwritten manuscripts
(The Eurographics Association, 2013) Pintus, Ruggero; Yang, Ying; Rushmeier, Holly; -
A massive digital acquisition of huge sets of deteriorating historical documents is mandatory due to their value and delicacy. The study and the browsing of such digital libraries is becoming crucial for scholars in the Cultural Heritage field, but it requires automatic tools for analyzing and indexing those dataset items. We present here a layout analysis method to perform automatic text height estimation, without the need of any kind of manual intervention and user defined parameters. It proves to be a robust technique in the case of very noisy and damaged handwritten manuscripts. The effectiveness of the method is demonstrated on a huge heterogeneous corpus of medieval manuscripts, with different writing styles, and affected by other uncontrollable factors, such as ink bleed-through, background noise, and overtyping text lines.
Realistic Virtual Reproductions. Image-based modelling of geometry and appearance
(The Eurographics Association, 2013) Martos, Antonio; Ruiz, Bernardino; -
Existing technologies for contact-less 3D scanning and Image Based Modelling (IBM) methods are being extensively used nowadays to digitize cultural heritage elements. With a convenient degree of automation these methods can properly capture and reproduce shape and basic colour textures. However, there is usually a quite evident lack of fidelity in the resulting appearance of the virtual reproductions when compared with the original items. Even when properly photo-textured, the reproduced surfaces often resemble either plaster or plastic, regardless of the properties of the original materials. What is neither captured nor modelled is the natural dynamic response of the actual materials with respect to changes in observation angle and/or the lighting arrangement. The methodology introduced in this paper tries to improve the three-dimensional digitalization and visualization of cultural heritage elements, by extending the present capabilities of IBM with additional capture and modelling of surface appearance. We show that it is possible to automatically reproduce realistic-looking virtual objects and scenes, even with photographs taken with an uncalibrated single moving camera and while under uncontrolled and intentionally variable lighting conditions. This is achieved not only by reconstructing the shape and projecting colour texture maps from photographs, but also modelling and mapping the apparent optical response of the surfaces to light changes, while also determining the variable distribution of environmental illumination of the original scene. This novel approach integrates Physically Based Render (PBR) concepts in a processing loop that combines capture and visualization. Using the information contained in different photographs, where the appearance of the object surface changes with environmental light variations, we show that it is possible to enhance the information contained in the usual colour texture maps with additional layers. This enables the reproduc- ion of finer details of surface normals and relief, as well as effective approximations of the Bi-directional Reflectance Distribution Function (BRDF). The appearance of the surfaces can then be reproduced with a dedicated render engine providing unusual levels of detail and realism due to enriched multi-layer texture maps and custom shading functions. This methodology will be introduced with a real case-study, to illustrate its practical applicability and flexibility; The virtual reproduction of the Lady of Elche was performed only from archived photographs taken at the museum for different documentation purposes, using uncalibrated optics and an uncontrolled studio light arrangement. We discuss the capture on larger architectural elements as well, with uncontrolled (yet still variable) illumination in outdoor environments and challenging items with difficult to capture surfaces such as the brass sculpture of La Regenta, where proper reproduction of surface reflection and environmental lights are fundamental steps to provide a good visualization experience. These cases will show the feasibility of working with field calibration and initial approximations for the camera model and light-maps, addressing thus the flexibility required for practical field documentation in museum environments or outdoors. The potential for diffusion will be shown with the use of open source software tools for enhanced visualization. The presented capture methods are integrated with the specific adaptation of open-source GPU-based (Graphics Processing Unit) render engines to produce two flavours of 3D inspection/visualization tools with proper relighting capabilities, able to reveal very subtle details: A quasi-real time realistic engine (Blender Cycles), which is also the basis for the capture process and is focused on realistic reproduction, and a real-time version based on customized pixel shaders, for the real-time visualization of lightweight models on web browsers and other interac
Automatic creation of bas-relieves from single images
(The Eurographics Association, 2013) Lorenzini, Cristian; Carrozzino, Marcello; Tecchia, Franco; Bergamasco, Massimo; -
When we think to bas-relieves it is natural to compare them with sculptures, because they share some common properties such as techniques, materials and shapes. However, from a different perspective, bas-relieves have even deeper connections with other bi-dimensional forms of art, such as the frescoes; both have been used to decorate walls surfaces, although bas-reliefs enabled different perspective of interpretation. Bas-relieves, in fact, extend themselves in the three-dimensional space and are therefore able to provide more information compared to an image representing the same scene; moreover, and not less interestingly, they are also enjoyable by users with special needs, such as blind people, that are able to explore their surfaces by means of their sense of touch. For this reason, many attempts have been made in the past to realize bas-relieves representing transpositions of bi-dimensional artworks such as images in order to improve their accessibility. Commonly these transpositions are manually made since manual procedures allow to retain the full control of the final result. The introduction of ICT tools such as 3D modeling and printing has allowed to simplify this process which however still results long and time-consuming, often aimed to one single specific case. In this paper we present an automatic system to enable a fast and massive production of 2.5D models, suitable to be transformed into simplified bas-relieves, starting from a single image, and providing an interactive editor in order to refine the results of the automatic reconstruction, designed for users having no special technical skills. The resulting digital models can be (optionally) refined with 3D modeling tools and directly used in Virtual Reality applications, for instance for educational purposes, or physically reconstructed as actual bas-reliefs to enable access to blind people. The paper details the methodology, the algorithm and presents the results obtained.
Building Information Modelling and the Documentation of Architectural Heritage: between the typical and the specific
(The Eurographics Association, 2013) Fai, Stephen; Sydor, Mikael; -
One of the greatest challenges to using Building Information Modelling (BIM) for the documentation of architectural heritage is in overcoming the propensity of the software toward standardization. Most BIM applications are optimized for industrialized building systems where even a minor deviation in geometry or dimension between like elements is considered problematic. Heritage buildings, on the other hand, are more typically constructed of unique elements that, while sometimes similar, can never be assumed to be identical. For example, two Corinthian capitals from the Temple of Mars Ultor may be similar, but they are not the same. In this paper, we discuss a novel method for developing a BIM for a unique vernacular building in eastern Ontario, Canada. Constructed anonymously in two discrete stages during the last half of the 19C, the builders employed both stacked log and an idiosyncratic balloon frame construction. Both types of construction are far from the standard assemblies found in commercial BIM software. In discussing the construction of the model, we will outline the integration of detailed survey data, including pointcloud, with a library of 'typical', but parametric, construction details under development by our research group. While the survey provides an accurate geometrical record of the building under discussion including structural deformations the library is used to develop the specific assemblies and is based on, and fully indexed to, 'typical' details culled from construction manuals available in Canada during the late 19C.
Aspects of the Digitalisation of the Documentation and Research of Lithuanian Historical Organs
(The Eurographics Association, 2013) Povilionis, Girenas; Povilioniene, Rima; -
About 450 historical organs have survived to the present day in Lithuania. Some of them are almost completely authentic instruments which constitute valuable heritage and have been recognised as being unique in European context. Currently the digitalisation of the data about the Lithuanian organ heritage is being implemented at the Centre for the Lithuanian Cultural Heritage since 2000 (until then non-digital data were accumulated) and is oriented towards the promotion of this part of the country's heritage, and scientific research. The most valuable instruments included on the heritage list are registered in detail: comprehensive photography of their separate parts and equipment, engineering data, as well as that of the surviving authentic mechanism and parts. A research into the instrumental part of some the most valuable organs (the organs in the church in Joniskis, the churches of the Holy Spirit and the Bernardine in Vilnius) is introduced. By the drawings it is possible to recreate an organ or make a copy-replica in case it is destroyed; the data can be used to make a new instrument according to old organ-making traditions.
Cellars of Paris, under the cobbles, cellars!
(The Eurographics Association, 2013) Sandron, Dany; Chaumet, Gregory; -
This project of systematic investigation of Parisian cellars is by nature pluri-disciplinary. It relies on the complementary skills of historians, architectural historians, archaeologists, architects and engineers. For several years, the Centre Chastel (UMR 8150) has developed a specific research axis about Paris, and is now associated with other organisations that have produced expert works and surveys on the development of the city based on documentary and archaeological materials: the Department for History of Architecture and Archaeology of Paris (DHAAP), the Heritage and inventory services of the Ile de France region, which benefits from a strong regional experience in the analysis of cellars, the National Archives and their centre on the historical topography of Paris and the INRAP engineers and archaeologists.
Visualizing a scanned model for effective heritage interpretation
(The Eurographics Association, 2013) Ahn, Jaehong; Kong, Dal-Yong; Wohn, Kwang-Yun; -
Scientific analysis of the scanned model can enhance interpretation of heritage. Visualization methods that use various rendering algorithm can reveal geometric features of the model clearly, which may not be recognized in pictures or even on the site. Thus it helps to overcome the subjectivity or restriction in first-hand interpretation. In this paper, visualization of scanned model for interpretation of heritage was surveyed. Based on that survey, a classification scheme was proposed which can be used in the interpretation pipeline. In a case study of dinosaur track, we analyzed the possible problems in the interpretation stage and proposed various visualization of scanned model according to the purpose. User test was performed to evaluate the effectiveness of the method. A practical survey in this paper showed that 3D scanned model and its appropriate visualization could be used for effective interpretation of heritage.
Measuring Changes in Cultural Heritage Objects with Reflectance Transform Imaging
(The Eurographics Association, 2013) Manfredi, Marcello; Williamson, Greg; Kronkright, Dale; Doehne, Eric; Bearman, Gregory; Jacobs, Megan; Marengo, Emilio; -
Sites and objects of cultural heritage from art to ancient inscriptions to ruins are under constant attack by time and the environment. While much is known about how material components change from laboratory-based artificial aging, very little is known about the process or rates of change of actual objects and sites in situ. Reflectance Transformation Imaging (RTI) is a quantitative method that captures surface normals. In our case, it provides detailed information on the geometry of the object surface. We show that RTI can be quantified for use as a method for measuring change in cultural heritage objects. The past decade has seen the rapid evolution and application of computational photography methods to document important works of human heritage, from art and architecture to archives and archaeology. The next logical step involves defining just how reproducible and precise these methods can be to use them to measure rates of change for important works of cultural heritage. The need is to move to calibrated, quantitative image datasets for reproducible imaging. We measure the precision of computed surface normals, which define the basic repeatability of RTI. Our results show that the average included solid angle for RTI sensitivity fitted to the Hemispherical Harmonics (HSH) polynomial function is 0.003 steradians (3 sigma), while the older Polynomial texture map (PTM) method is much less sensitive (0.5 steradians). The absolute sensitivity of the method is the minimum variation of the normal that can be statistically considered a change of the object. It is calculated considering the average value of the normal of each single pixel. The solid angle of the cone of variation represents the statistical limit (3 *s). Analysis of multiple RTI data sets from objects that have changed between image capture sessions results in a map of change that can easily be evaluated by conservators.

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