Search Results

Now showing 1 - 10 of 23
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    Geometry-aware Video Registration
    (The Eurographics Association, 2010) Palma, Gianpalo; Callieri, Marco; Dellepiane, Matteo; Corsini, Massimiliano; Scopigno, Roberto; Reinhard Koch and Andreas Kolb and Christof Rezk-Salama
    We present a new method for the accurate registration of video sequences of a real object over its dense triangular mesh. The goal is to obtain an accurate video-to-geometry registration to allow the bidirectional data transfer between the 3D model and the video using the perspective projection defined by the camera model. Our solution uses two different approaches: feature-based registration by KLT video tracking, and statistic-based registration by maximizing the Mutual Information (MI) between the gradient of the frame and the gradient of the rendering of the 3D model with some illumination related properties, such as surface normals and ambient occlusion. While the first approach allows a fast registration of short sequences with simple camera movements, the MI is used to correct the drift problem that KLT tracker produces over long sequences, due to the incremental tracking and the camera motion. We demonstrate, using synthetic sequences, that the alignment error obtained with our method is smaller than the one introduced by KLT, and we show the results of some interesting and challenging real sequences of objects of different sizes, acquired under different conditions.
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    Principles and Practices of Robust, Photography-based Digital Imaging Techniques for Museums
    (The Eurographics Association, 2010) Mudge, Mark; Schroer, Carla; Earl, Graeme; Martinez, Kirk; Pagi, Hembo; Toler-Franklin, Corey; Rusinkiewicz, Szymon; Palma, Gianpaolo; Wachowiak, Melvin; Ashley, Michael; Matthews, Neffra; Noble, Tommy; Dellepiane, Matteo; Alessandro Artusi and Morwena Joly and Genevieve Lucet and Denis Pitzalis and Alejandro Ribes
    This full day tutorial will use lectures and demonstrations from leading researchers and museum practitioners to present the principles and practices for robust photography-based digital techniques in museum contexts. The tutorial will present many examples of existing and cutting-edge uses of photography-based imaging including Reflectance Transformation Imaging (RTI), Algorithmic Rendering (AR), camera calibration, and methods of imaged-based generation of textured 3D geometry. Leading museums are now adopting the more mature members of this family of robust digital imaging practices. These practices are part of the emerging science known as Computational Photography (CP). The imaging family's common feature is the purpose-driven selective extraction of information from sequences of standard digital photographs. The information is extracted from the photographic sequences by computer algorithms. The extracted information is then integrated into a new digital representations containing knowledge not present in the original photographs, examined either alone or sequentially. The tutorial will examine strategies that promote widespread museum adoption of empirical acquisition technologies, generate scientifically reliable digital representations that are born archival', assist this knowledge's long-term digital preservation, enable its future reuse for novel purposes, aid the physical conservation of the digitally represented museum materials, and enable public access and research.
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    The ArchAIDE Project: Results and Perspectives After the First Year
    (The Eurographics Association, 2017) Banterle, Francesco; Dellepiane, Matteo; Evans, Tim; Gattiglia, Gabriele; Itkin, Barak; Zallocco, Massimo; Tobias Schreck and Tim Weyrich and Robert Sablatnig and Benjamin Stular
    The ArchAIDE project is a Horizon 2020 project that has the main goal to digitally support the day-to-day operations on the field of archaeologists. This allows them to reduce time and costs of delivering an accurate and quick classification of ancient pottery artifacts. To effectively reach such ambitious goal, the project has several sub-goals: (semi-)automatic digitalization of archaeological catalogs, a mobile app to be used on site for live classification of sherds with the generation of a complete potsherds identity card (ready for print), and an on-line database with real-time visualization of data. In this paper, we describe the work carried out during the first year of life of this project. The main focus is on the procedure for digitizing paper catalogs in an automatic way, and more precisely we will discuss: archeologist's methodologies, digitalization of text, vectorization of technical drawings, and shape-based classification of virtual fragments.
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    Digital reconstruction and visualization in archaeology. Case-study drawn from the work of the Swedish Pompeii Project
    (The Eurographics Association, 2013) Dell'Unto, Nicolò; Ferdani, Daniele; Leander, Anne Marie; Dellepiane, Matteo; Callieri, Marco; Lindgren, Stefan; -
    The Swedish Pompeii Project started in 2000 as a research and fieldwork activity initiated by the Swedish Institute in Rome. The aim was to record and analyze an entire Pompeian city-block, Insula V 1. Since autumn 2011 a new branch of advanced digital archaeology, involving 3D reconstructions and documentation methods, was added to the project agenda. The insula was completely digitized using laser scanner technology and the raw data were employed to develop different research activities in the area of digital visualization. This paper presents the recent results of the 3D interpretation of the house of Caecilius Iucundus. This research activity was developed employing a large variety of historical and archaeological sources such as: archaeological reports, historical image documentation (printed as well as in edited material) and analysis of the in situ structures. This work was characterized by the experimentation of a new workflow of data development, where the elaboration of the interpreted structures took place directly in virtual space, using the scanned model as geometrical reference. This method easily connected all the historical and archaeological sources collected for the interpretation, opening a new discussion about different possible interpretation of the house. Moreover, a Cave Automatic Virtual Environment (CAVE) was used in different occasions as platform where the different hypotheses could be discussed in the context given by the actual state of the archaeological structures. The use of an accurate and resolute replica of the site as a backdrop for the virtual reconstruction allowed a high level of control on the proposed hypotheses during the interpretation process. This study enabled the acquisition of new and important information about the house, thus, bringing a significant contribution to the archaeological analysis of Insula V 1, suggested as pilot project for wider use.
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    Automating Large 3D Dataset Publication in a Web-Based Multimedia Repository
    (The Eurographics Association, 2016) Potenziani, Marco; Fritsch, Bernhard; Dellepiane, Matteo; Scopigno, Roberto; Giovanni Pintore and Filippo Stanco
    Online publishing of almost every type of 3D data has become a quasi-standard routine. Nevertheless, the integration in a web page of a single 3D model, or of a predefined restricted set of models, raises different issues compared to an efficient and effective integration of thousands of them in an online repository. In this case it is mandatory to have an automatized pipeline to prepare and homogenize the dataset. The pipeline should be able to automatically wrap 3D data in all conditions, and display every single model with the best scene setup without any (or with a minimal) interaction by the database maintainers. This paper, retracing the steps of a recent real application case, aims at showing all the faced issues (and the adopted solutions) to publish a large and heterogeneous three-dimensional dataset in a web specialized repository. We want to introduce a valid and reusable strategy, starting from the description of the pipeline adopted for data pre-processing and moving to the choices made in the 3D viewer implementation. The paper concludes with a discussion on the actual state of the integration of 3D data with the other multimedia informative layers.
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    Improving High-Speed Scanning Systems by Photometric Stereo
    (The Eurographics Association, 2011) Larue, Frédéric; Dellepiane, Matteo; Scopigno, Roberto; Franco Niccolucci and Matteo Dellepiane and Sebastian Pena Serna and Holly Rushmeier and Luc Van Gool
    High-speed scanning systems can be extremely valuable for Cultural Heritage applications, especially when large collections of small objects have to be acquired. However, fine details may not be acquired using this technology. Nevertheless, it is possible to try to recover them by taking advantage of the additional data provided by these systems: the calibrated video sequence of the acquisition, and the position of the projector light for each frame. In this paper, we propose a workflow that processes the video sequence with a photometric stereo approach, in order to refine the coarse geometry provided by the scanner. A normal map is first extracted by a method that accounts for the unevenly distributed sampling that generally results from the particular trajectory followed by this kind of scanners during the acquisition. This normal map is then integrated in order to recover missing geometric features. Good performances are achieved, since the whole workflow is particularly suited to GPU programming.
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    A Statistical Method for SVBRDF Approximation from Video Sequences in General Lighting Conditions
    (The Eurographics Association and Blackwell Publishing Ltd., 2012) Palma, Gianpaolo; Callieri, Marco; Dellepiane, Matteo; Scopigno, Roberto; Fredo Durand and Diego Gutierrez
    We present a statistical method for the estimation of the Spatially Varying Bidirectional Reflectance Distribution Function (SVBRDF) of an object with complex geometry, starting from video sequences acquired with fixed but general lighting conditions. The aim of this work is to define a method that simplifies the acquisition phase of the object surface appearance and allows to reconstruct an approximated SVBRDF. The final output is suitable to be used with a 3D model of the object to obtain accurate and photo-realistic renderings. The method is composed by three steps: the approximation of the environment map of the acquisition scene, using the same object as a probe; the estimation of the diffuse color of the object; the estimation of the specular components of the main materials of the object, by using a Phong model. All the steps are based on statistical analysis of the color samples projected by the video sequences on the surface of the object. Although the method presents some limitations, the trade-off between the easiness of acquisition and the obtained results makes it useful for practical applications.
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    Alchemy in 3D - A Digitization for a Journey Through Matter
    (IEEE, 2015) Callieri, Marco; Pingi, Paolo; Potenziani, Marco; Dellepiane, Matteo; Pavoni, Gaia; Lureau, Aurelia; Scopigno, Roberto; Gabriele Guidi and Roberto Scopigno and Pere Brunet
    In this work, we will present the outcomes of the 3D diagnostic investigations carried out on the painting Alchemy by Jackson Pollock. Thanks to an accurate digitization and a careful processing, we were able to generate a very precise high-resolution 3D model that proved to be useful in different stages of the diagnostic and conservation campaign. The 3D model was integrated in the conservation process, along with the other diagnostic investigations; the geometric data was also used to produce images and video sequences for dissemination purposes. The most interesting aspect of the work, however, was the idea of going beyond photo-realism and the use of the scanner-measured geometry to try to interpret and understand the traces and signs on the surface of the painting, in relation with the gestures and techniques used by Pollock while painting this masterpiece. Combining the knowledge of the curators and the metric data gathered in the digitization, we were able to discover and validate several interesting aspects of the painting, in the direction of trying to better understanding the painting process which was, in the idea of the artist, an essential part of the artwork. The 3D model of the artwork played a central role also in the temporary exhibition created for the dissemination of the conservation and the diagnostic campaign to the museum visitors. This was also done following the idea of using the geometry to explain the gestures, actions and techniques of Jackson Pollock at work. The 3D model was used to create an interactive kiosk, to have the visitors navigate the model and access explanations of relevant geometrical details and to produce a 1:1 physical reproduction to give the public the possibility to physically interact with the artwork.
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    Removing Shadows for Color Projection Using Sun Position Estimation
    (The Eurographics Association, 2010) Dellepiane, Matteo; Benedetti, Luca; Scopigno, Roberto; Alessandro Artusi and Morwena Joly and Genevieve Lucet and Denis Pitzalis and Alejandro Ribes
    The result of an outdoors 3D scanning acquisition campaign is usually an accurate 3D model of the site, but in most of the cases the quality of the color acquired by the scanner is not satisfying. Alternative solutions, like the projection of a photographic dataset acquired in a different stage, are still dependent on the quality of the initial images. The short time for the acquisition campaigns and the weather conditions often force the shooting of images taken under a strong direct sun illumination. This generates colored models of poor quality. In this paper we present a method to estimate the sun position starting from a geo-referenced 3D model and a set of images. The sun position can enhance both the image alignment and color projection phases. Moreover, the detection and removal of the shadows from the images produces a better and more coherent color in the final 3D model. Using this kind of approach, outdoor sites can be acquired producing a high quality color information together with an accurate geometric measurement.
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    Site-specific Art and 3D: an Example of Spatial Analysis and Reconstruction
    (The Eurographics Association, 2014) Dellepiane, Matteo; Matteis, Mara De; Reinhard Klein and Pedro Santos
    Site-specific art is a concept that goes back to the beginning of human race: the works of art were often created by artists taking into account not only their shape and appearance, but also the context in which they would be put. For this reason, moving the artifacts from its original placement (or the changes which happen around it) tend to decrease its impact, and possibly weaken its potentials. Site-specific art is a very powerful concept also for contemporary artists. This paper focuses on the analysis of L.O.V.E., a sculpture from the controversial artist Maurizio Cattelan. Cattelan donated the sculpture to Milano, under the condition that it should not be moved from its original place (in front of Milano Stock Exchange). The aim of the paper is to use 3D reconstruction techniques to show and analyse the monument, stressing its relation with the context around it. A multi-view stereo matching campaign was perfomed to have an accurate reconstruction of the context, then the photos provided by the community were integrated in the reconstruction to show the "point of view" of the people. These data provide interesting indications about the aims of the authors, and they provide additional material for the interpretation of the work of art.