DH2013 - Track 1

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https://diglib.eg.org/handle/10.2312/12322

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3D documentation and monitoring of the experimental cleaning operations in the underwater archaeological site of Baia (Italy)
(The Eurographics Association, 2013) Bruno, Fabio; Gallo, Alessandro; Filippo, Francesco De; Muzzupappa, Maurizio; Davidde, Barbara; Caputo, Paolo; -
The CoMAS project aims to develop new methodologies and tools for the restoration and conservation of submerged archaeological artefacts. One of the project goals is to study the cleaning operations that are intended to remove the living organisms (algae, sponges, molluscs, etc.). These organisms cause severe deteriorations of the artefacts and their removal is crucial for the subsequent phases of consolidation and protection. In particular, the Unit of Underwater Archaeology of the Istituto Superiore per la Conservazione ed il Restauro is experimenting and comparing different cleaning techniques and tools developed in the context of the CoMAS project. This comparison requires also a precise documentation of the test cases and a quantitative measurement of the effectiveness of the cleaning procedures. This paper describes the process that has been defined in order to document and monitor the results obtained through different cleaning experiments, conducted with different tools and utensils over various types of surfaces (marble, bricks, mortar, etc.) affected by several types of biological colonization. The process includes: 1) the 3D mapping of the experimental site; 2) the planning of the tests and the choice of the areas to be cleaned; 3) the 3D reconstruction of the selected areas; 4) the execution of cleaning operations; 5) the 3D acquisition of the cleaned areas; 6) the comparison of the 3D model of the areas before and after the cleaning; 7) the analysis of the data about the cleaning effectiveness. This process has been implemented during an experimentation carried out in the ''Villa dei Pisoni'', located within the underwater archaeological site of Baia near Naples.
3D documentation of Cultural Heritage artefacts: from data acquisition to virtual conservation and restoration
(The Eurographics Association, 2013) Athanasiou, Eleni; Faka, Marina; Hermon, Sorin; Vassallo, Valentina; Yakoupi, Kyriaki; -
This paper focuses on the development of a procedure for 3D documentation of Cultural Heritage assets and describes all the steps from the 3D data acquisition of the real object, the post processing the raw data and finally the digital recording, documentation and virtual preservation of the 3D data. It will also describe the experiences, carried out during the digital process, of some virtual restoration cases.
3D Laser Scanning in Cave Environment: the Case of Las Cuevas, Belize. Acquisition of the Cave System and Excavation Area
(The Eurographics Association, 2013) Lindgren, Stefan; Galeazzi, Fabrizio; -
The Las Cuevas site is a Maya administrative and ceremonial center active during the latter part of the Late Classic period (700 900 AD) in Western Belize. It is of particular interest because a large cave resides directly beneath the largest temple in the site core. This paper presents the use of phase shift variation laser scanning technology (Faro Focus 3D) for the acquisition of the cave's network of galleries (9 chambers) and a large excavation area (8×5 m) investigated in the entrance chamber in the summer of 2012. More than 300 scans were made to acquire the entire cave and the amount of 3D data collected was more than 400 GB. The creation of different level of details allowed the alignment and triangulation of the 3D models of the different chambers and units. The dimension (24×20×10 cm; 5 kg) and accuracy (' 2 mm at 10 25 m) of the laser scanner allowed complete documentation of the cave and units in just three weeks of work. The importance of this work relies on the possibility to use the processed data to systematically improve the archaeological understanding of Las Cuevas' complex cave system, favoring the interpretation of socio-cultural dynamics linked to cave environments during the Late Classic. The use of 3D technologies can, in fact, help the understanding of how the space in the cave was used in the past for rituals and ceremonies. Moreover, the 3D millimetric reproduction of the excavation process linked to the 3D survey of the entire cave will be instrumental for the archaeological record's preservation. Future scholars will have the opportunity to retrace the work made by archaeologists at Las Cuevas, starting new discussion and interpretations of the same 3D archaeological context.
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.
3D Reconstruction of the Cave of the Great Pyramid from Video Footage
(The Eurographics Association, 2013) Kawae, Yukinori; Yasumuro, Yoshihiro; Kanaya, Ichiroh; Chiba, Fumito; -
Studies on the great pyramid of King Khufu (2509-2483 BCE '25) in Egypt are numerous, but only a few surveys, which are the basis of any hypotheses on the construction of a pyramid, have been conducted. In particular, since no observation of the core of the pyramid has been made, theories about the structure are still hypothetical. In 2013, a Japanese TV production company had the opportunity to climb the northeast corner of the pyramid to shoot a crevice that led to an open space (named ''cave'') inside the pyramid, located about 80m from the ground. The authors are fortunate to be allowed to use this video footage for academic research. We employed a ''structure from motion'' (SfM) technique using Microsoft Photosynth to reconstruct the 3D point cloud of the surface of the cave. Twenty minutes of footage was split into thirty thousand image frames, out of which we selected three hundred images shot using several smooth motions of the camera and used these for the SfM process. SfM tracks the ''feature points'' in the image sequence to estimate the camera motion and then triangulates these feature points to produce the point clouds. As a result, the static feature points from the overall surface of the cave were effectively collected and reconstructed as point clouds, whereas inconsistent points from a moving person are automatically eliminated through the SfM process. Thus we have produced, albeit in a small area, the first record of the actual structure of the great pyramid's core. The production of a 3D model from existing video footage is a rather new methodology in the field of archaeology. This set of techniques can be applied to not only academic investigation but also to the restoration and conservation of damaged heritage and artifacts.
Anomaly Detection using Remote Sensing for the Archaeological Heritage Registration
(The Eurographics Association, 2013) Rejas, Juan Gregorio; Burillo, Francisco; Bonatti, Javier; Martínez, Rubén; -
The aim of this work is an approach using multisensor remote sensing techniques to recognize the potential remains and recreate the original landscape of three archaeological sites. We investigate the spectral characteristics of the reflectance parameter and emissivity in the pattern recognition of archaeological materials in several hyperspectral scenes of the prehispanic site in Palmar Sur (Costa Rica), the Jarama Valley site and the celtiberian city of Segeda in Spain. Spectral ranges of the visible-near infrared (VNIR), shortwave infrared (SWIR) and thermal infrared (TIR) from hyperspectral data cubes of HyMAP, AHS, MASTER and ATM have been used. Several experiments on natural scenarios of Costa Rica and Spain of different complexity, have been designed. Spectral patterns and thermal anomalies have been calculated as evidences of buried remains and change detection. First results, land cover change analyses and their consequences in the digital heritage registration are discussed.
Characterization of European Lacquers by terahertz (THz) reflectometric imaging
(The Eurographics Association, 2013) Dandolo, Corinna Ludovica Koch; Jepsen, Peter Uhd; -
In this study a European lacquerware replica has been investigated by terahertz (THz) reflectometric imaging. The inspected lacquerware is a wooden panel covered by multiple complex layers of lacquers and plaster. Utilizing pulsed Terahertz Time-Domain Imaging (THz-TDI) in reflection mode, we observe non-invasively buried layers of the lacquerware replica, including the internal structure of the wooden panel itself. We find that non-invasive terahertz reflectometric imaging analysis of lacquerware is can provide conservators with important information about the condition of the compositional layers, potentially aiding in the development of appropriate conservation treatments. With the same technique we have performed a surface material mapping. The material distribution has been enhanced through reflected THz composite RGB false color rendering, where RGB mapping allows distinction between different materials and textures on the surface of the lacquerware. The contrast between different textures is enabled by wavelength-dependent scattering from the surface, as well as differences in the composition of the surface layer.
Comparing 3D digitising technologies: where are the differences?
(The Eurographics Association, 2013) Mathys, Aurore; Brecko, Jonathan; Semal, Patrick; -
We tested five 3D digitization systems and one method of 2D+ recording on one object: a human skull from the Royal Belgian Institute of Natural Sciences collection (RBINS). We chose a skull because it has both simple and complex structures and different materials such as bone and enamel within the same object. The results obtained with the different technologies were compared for 3D shape accuracy, texture quality, digitization and processing time and finally price. Our results show that the structured light scanner provided the best results to record external structures, CT was found to be the best to record internal structures and is also the best for recording reflecting material such as enamel. Photogrammetry is a very good compromise between portability, price and quality. RTI is a method of 2D+ recording and is a complementary technique, using the same equipment than photogrammetry, which can capture small morphological features that are not easily digitized with the 3D techniques.
Cultural heritage documentation using geomatic techniques; Case study: San Basilio s monastery
(The Eurographics Association, 2013) Dominici, Donatella; Rosciano, Elisa; Alicandro, Maria; Elaiopoulos, Michail; Trigliozzi, Serena; Massimi, Vincenzo; -
Each community, passing through its history and its collective memories, has the duty to conserve, identify and properly manage its own heritage that, unfortunately, is often susceptible to transformations due to time, anthropogenic factors or damages caused by natural phenomena. For this reason, heritage artifacts are being extensively documented in order to be maintained in the very best way and bestowed for the benefit of future generations. Geomatic techniques (total stations, GNSS receivers and laser scanners), when integrated among them in an appropriate surveying methodology, data management and processing, can provide dedicated methodologies able to detect and survey the particular characteristics of such complicated structures. In this way, 3D geometric models of the building can be created and enriched with a wide range of information, results of the combination between the visual potential of the images with the high accuracy of the geometric survey. Thus, the use of geomatics represents an interesting tool both for the visualization and the metric evaluation of the structure itself providing an efficient support for professionals and public bodies. The survey of the old monastery of San Basilio, a 16th century building in L'Aquila, central Italy, is presented in this paper.
Cutting-edge technologies for the survey and documentation of cultural heritage: the case study of the architectural-archaeological area of Aruch in Armenia
(The Eurographics Association, 2013) Versaci, Antonella; Cardaci, Alessio; -
One of the most important finalities of survey is the architecture's comprehension. To the end of cultural heritage conservation, it is furthermore necessary to communicate the acquired knowledge. In the recent years, this need has resulted in a radical change in cataloging and digitization systems, as well as in telematics networking. Moreover, the use of 3D laser scanner has transformed not only the approaches related to metrics data acquisition and graphic rendering but has also afforded the opportunity to share important information on the web. This paper focuses on the usefulness of state-of-the-art technologies for documentation, presenting a case study related to the architectural-archeological area of Aruch in Armenia.
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.
Design and implement a reality-based 3D digitisation and modelling project
(The Eurographics Association, 2013) Remondino, Fabio; Menna, Fabio; Koutsoudis, Anestis; Chamzas, Christos; El-Hakim, Sabry; -
3D digitisation denotes the process of describing parts of our physical world through finite measurements and representations that can be processed and visualised with a compute r system. Reality-based 3D digiti sation is essential for the documentation, conservation and preservation of our Cultural Heritage. This article composes a critical review of the digitisation pipeline, ranging from sensor selection and planning to data acquisition, processing and visualisation.
Digital Production of Traditional Costumes
(The Eurographics Association, 2013) Kang, Yeonkyung; Wu, Sehee; Ko, Young-A; Martin, Kathi; Ko, Hyeong-Seok; -
The role of the museum has changed from a "onesided information delivery" system focusing on exhibition and education to ''community as culture''. Creating richly detailed digitized reproductions of museum holdings can stimulate the social media dialogue between museum and visitor. The purpose of this study is to determine the feasibility of reproducing traditional costumes using digital technology. For this experiment, we selected a woman's robe and a man's ensemble of the Rococo era of the 18th century. Using historical reference material we first analyzed the design features of the silhouette, and the fabrics, hairdos and accessories of the period. This paper details the application of 3D technologies, DC Suite and Maya Qualoth, to reconstruct them.
Faithful, Compact and Complete Digitization of Cultural Heritage using a Full-Spherical Scanner
(The Eurographics Association, 2013) Nöll, Tobias; Köhler, Johannes; Reis, Gerd; Stricker, Didier; -
Effective documentation and display of ancient objects is an essential task in the field of cultural heritage conservation. Digitization plays an important role for the process of creating, preserving and accessing objects in digital space. Up to the present day, industrial scanners are used for this task that focus mainly on the detailed reconstruction of the object's geometry only. However, important for a faithful digital presentation of the object is in particular the appearance information, i.e. a description of the used materials and how they interact with incident light. Using the worlds first full-spherical scanner, we propose a user friendly reconstruction process that is specifically tailored to the needs for digitizing and representing cultural heritage artifacts. More precisely, our hardware specifically addresses the problem that invaluable or fragile artifacts may not be turned over during acquisition. Nevertheless, we can digitize the object completely including its bottom. Further, by integrating appearance information into our digitization we achieve a far more faithful digital replica with a quality comparable to a real picture of the object. But in contrast to a static picture, our representation allows to interactively change the viewing and lighting directions freely. In addition, the results are very memory efficient, consuming only several MB per scanned object and hence are suited to be accessed and visualized interactively in a web browser. In cooperation with museums and a private collector, we digitized several cultural heritage artifacts in order to demonstrate the feasibility of the proposed process.
Feature-based automatic 3D registration for cultural heritage applications
(The Eurographics Association, 2013) Tombari, Federico; Remondino, Fabio; -
This paper presents a review of the state-of-the-art techniques in the field of 3D invariant features for the automatic registration of point clouds and 3D meshes. The paper proposes also a multi-stage 3D registration pipeline implemented using the PCL libraries. Experiments are carried out on datasets related to heritage scenarios and addressing large-scale outdoor data acquisitions as well as small objects.
Global refinement of image-to-geometry registration for color projection on 3D models
(The Eurographics Association, 2013) Dellepiane, Matteo; Scopigno, Roberto; -
The management, processing and visualization of color information is a critical subject in the context of the acquisition and visualization of real objects. Especially in the context of Cultural Heritage, artifacts are so complex or hard-to-handle that the appearance information has to be extracted from a set of images. The images usually have to be registered to the 3D model of the objects, in order to transfer the needed information. Hence, the problem of image-to-geometry registration has been thoroughly studied by the Computer Graphics and Computer Vision community. Several methods have been proposed, but a fully automatic and generic solution is still missing. Moreover, small misalignments often lead to visible artifacts in the final colored 3D models. In this paper, we propose a method to refine the alignment of a group of images which has been already registered to a 3D model. Taking advantage of the overlapping among the images, and applying a statistical global method based on Mutual Information, the registration error is distributed among all the elements of the dataset. Hence, the quality of color projection is improved, especially when dealing with small details. The method was tested on a number of heterogeneous Cultural Heritage objects, bringing to a visible improvement in the rendering quality. The method is fully automatic, and it does not need powerful hardware or long processing time. Hence, it represents a valid solution for a wide application on CH artifacts.
GNSS role in planning and conductance of terrain archaeological survey: technical aspects and methodology
(The Eurographics Association, 2013) Stamenov, Stefan; Naydenova, Vanya; -
The purpose of the present paper is to present the technical aspects and the methodological framework of applying non-destructive methods and technologies for planning and conductance of terrain archaeological survey. The remote sensing methods together with the GNSS and geoinformation technologies play an important role in the terrain survey. The proposed approach is focused on the technical aspects of applying GNSS technologies in the field work. This approach was applied on the Early-Medieval archaeological object Kabiyuk, located in Northeast Bulgaria, announced as a National Historical and Archaeological Reserve in 2012. Kabiyuk is one of the main archaeological sites connected with the First Bulgarian Kingdom, whose earthen rampart is at second place after the fortification of the First Bulgarian Capital Pliska. The methodological framework for terrain survey includes four main stages planning of the terrain archaeological survey; preliminarily survey of the archaeological site; conductance of the terrain survey and GNSS measurements and post-processing of the recorded data and collected information. During the planning of the terrain archaeological survey, information from remote sensing data (satellite images and aerial photos) was used to define the areas without built-up lands or thick forests, waters bodies. In the second stage a preliminarily survey were conducted during which areas without vegetation cover were defined on which archeological surveys will be carried out. The terrain survey was conducted using preliminarily generated digital grid, which was applied for the first time in the investigation of the First Bulgarian capital Pliska by the same team. A GNSS receiver with high accuracy is required for navigation according to the digital grid and for registration the discovered new potential archaeological objects, and as well as for detailed archaeological mapping.
Improving the digitization of shape and color of 3D artworks in a cluttered environment
(The Eurographics Association, 2013) Bettio, Fabio; Gobbetti, Enrico; Merella, Emilio; Pintus, Ruggero; -
We propose an approach for improving the digitization of shape and color of 3D artworks in a cluttered environment using 3D laser scanning and flash photography. In order to separate clutter from acquired material, semi-automated methods are employed to generate masks for segment the 2D range maps and the color photographs, removing unwanted 3D and color data prior to 3D integration. Sharp shadows generated by flash acquisition are trivially handled by this masking process, and color deviations introduced by the flash light are corrected at color blending time by taking into account the object geometry. The approach has been applied to, and evaluated on, a large scale acquisition campaign of the Mont'e Prama complex, an extraordinary collection of stone fragments from the Nuragic era, depicting larger-than-life archers, warriors, boxers, as well as small models of prehistoric nuraghe (cone-shaped stone towers). The acquisition campaign has covered 36 statues mounted on metallic supports, acquired at 0.25mm resolution, resulting in over 6200 range scans (over 1.3G valid samples) and 3426 10Mpixel photographs.
Integrated method for tracking changes in archeo-landscapes using remote and close-range technologies
(The Eurographics Association, 2013) Agapiou, Athos; Cuca, Branka; Themistocleous, Kyriakos; Alexakis, Dimitiros D.; Hadjimitsis, Diofantos G.; -
The importance of visible built heritage and archeolandscapes for preservation of collective memory and identity is widely acknowledged across disciplines regarding heritage protection and valorisation. The complex analysis of archaeolandscape transformations through time needs multilevel geospatial information. To this purpose, it is necessary to consider different domains of technological tools but also an appropriate geospatial framework, applying a multi-scale, multi-temporal and multi-sensor approach. In this way, the capabilities of new technologies can be further expanded aiming towards to an effective integration and improvement of preservation strategies and protection methodologies for cultural heritage sites. This paper illustrates the integration of in situ surveying campaigns, close range photogrammetry, aerial and satellite remote sensing imagery for identify change detection at the ''Nea Paphos'', a UNESCO protected archaeological site of Cyprus. In particular, this paper examines the evolution of a buried archaeological feature (amphitheatre?) which is already known to experts but has not yet been excavated. Changes of shape and size have been documented, interpreted and mapped using resources covering a temporal arch of circa last 50 years. While soil and vegetation marks of the buried feature are very clear in the historic aerial imagery, these traces are disturbed on the recent images. An integrated method of detecting natural and physical consequences for evolving landscapes, using remote sensing techniques, airborne, and 3D photogrammetric models developed using open-source tools has been applied. Such integration is envisaged to (1) provide new kind of information and possible scenarios for retrieving geospatial knowledge of evolving archeolandscapes and their multiple layers of history and to (2) enable archaeologists, public administration and conservation professionals to pursue specific tailored-made preservation strategies o- specific archaeological sites and to support them in more informed decision making.
Low-cost mobile system for multispectral cultural heritage data acquisition
(The Eurographics Association, 2013) Blazek, Jan; Soukup, Jindrich; Tichý, Tomás; Zitova, Barbara; Hradilová, Janka; Flusser, Jan; -
In the paper we propose an alternative approach to the multispectral data acquisition of the cultural heritage artifacts. The demonstrated solution is mobile, affordable, and consists only of commercial off-the-shelf products. It could be used for the data acquisition in-situ without limitations. It was designed for multispectral scanning of cultural heritage artifacts for their first analysis, for multimedia presentations dedicated to public, and, of course, for art conservation studies. The presented solution contains next to the hardware part as well the description of pre-analysis step two alternative ways of the photometric calibration to ensure the anticipated precision. The applicability of the framework was demonstrated on the case study, the preliminary spectral analysis. The proposed methodology is successfully used in the art restoration practice.

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