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Now showing 1 - 8 of 8
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    Selective Rasterized Ray-traced Reflections on the GPU
    (The Eurographics Association, 2016) Kastrati, Mattias Frid; Goswami, Prashant; Giovanni Pintore and Filippo Stanco
    Ray-tracing achieves impressive effects such as realistic reflections on complex surfaces but is also more computationally expensive than classic rasterization. Rasterized ray-tracing methods can accelerate ray-tracing by taking advantage of the massive parallelization available in the rasterization pipeline on the GPU. In this paper, we propose a selective rasterized raytracing method that optimizes the rasterized ray-tracing by selectively allocating computational resources to reflective regions in the image. Our experiments suggest that the method can speed-up the computation by up to 4 times and also reduce the memory footprint by almost 66% without affecting the image quality. We demonstrate the effectiveness of our method using complex scenes and animations.
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    3D Digital Imaging for Knowledge Dissemination of Greek Archaic Statuary
    (The Eurographics Association, 2016) Stanco, Filippo; Tanasi, Davide; Allegra, Dario; Milotta, Filippo L. M.; Giovanni Pintore and Filippo Stanco
    This paper aims, using a research exercise, to verify the association between two Greek sculptures collected at different times: the head of a boy collected in the Chalcidian colony of Leontinoi in southeastern Sicily, acquired in the 18th century and later kept in the collection of the Museum of Castello Ursino in Catania, and a torso, retrieved in 1904 and since then displayed in the Archaeological Museum of Sicily. The two pieces share similar stylistic features and represent the most significant example of Greek sculpture in Sicily at the end of the 6th century BC. Their association is an open problem still debated by scholars, who have based their studies on comparisons between pictures as a reassembly of two artefacts was never attempted. This critical issue has conditioned curators of the two museums, who could not develop a proper communication policy for the two objects, resulting in a limited cognitive accessibility for the public. By means of 3D scanning techniques, this contribution showcases how virtual restoration can not only improve interpretations of the scholars, but also boost the communication plans of museums, giving back to the public via a web platform a masterpiece of Greek sculpture known just by specialists.
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    Anisotropic MatCap: Easy Capture and Reproduction of Anisotropic Materials
    (The Eurographics Association, 2016) Magri, Dario; Cignoni, Paolo; Tarini, Marco; Giovanni Pintore and Filippo Stanco
    We propose Anisotropic MatCap, a simple data structure based on a small volumetric texture that is able to represent, under a fixed lighting, the behavior of anisotropic materials. The data structure is designed to allow fast and practical capture of real-world anisotropic materials (like for example fabrics) and to be used in real-time renderings, requiring only negligible time and texture memory overheads. The resulting technique is suited for application scenarios where digital objects must be inspected by an end user, recreating the look of an object made of a captured anisotropic material and seen under the predetermined lighting conditions. The technique proved particularly useful for garments and cloth visualization and design.
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    Low Cost Handheld 3D Scanning for Architectural Elements Acquisition
    (The Eurographics Association, 2016) Allegra, Dario; Gallo, Giovanni; Inzerillo, Laura; Lombardo, Marcella; Milotta, Filippo L. M.; Santagati, Cettina; Stanco, Filippo; Giovanni Pintore and Filippo Stanco
    3D scanning has gone a long way since its first appearance in cultural heritage digitization and modeling. In the recent years some new low cost, fast, accurate emerging technologies are flooding the market. Envisioning the massive use of these cheap and easy to use devices in the next years, it is crucial to explore the possible fields of application and to test their effectiveness in terms of easiness of 3D data collection, processing, mesh resolution and metric accuracy against the size and features of the objects. In this study we focus the attention on one emerging technology, the Structure Sensor device, in order to verify a 3D pipeline acquisition on an architectural element and its details. The methodological approach is thought to define a pipeline of 3D acquisition exploiting low cost and open source technologies and foresees the assessment of this procedure in comparison with data obtained by a Time of Flight device.
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    Mobile Multiview Diffuse Texture Extraction
    (The Eurographics Association, 2015) Kán, Peter; Kaufmann, Hannes; Andrea Giachetti and Silvia Biasotti and Marco Tarini
    This paper presents a novel method for diffuse texture extraction from a set of multiview images. We address the problem of specularities removal by pixel value minimization across multiple automatically aligned input images. Our method is based on the fact that the presence of specular reflection only increases the captured pixel value. Moreover, we propose an algorithm for estimation of material region in the image by optimization on the GPU. Previous methods for diffuse component separation from multiple images require a complex hardware setup. In contrast to that, our method is highly usable because only a mobile phone is needed to reconstruct diffuse texture in an environment with arbitrary lighting. Moreover, our method is fully automatic and besides capturing of images from multiple viewpoints it does not require any user intervention. Many fields can benefit from our method, particularly material reconstruction, image processing, and digital content creation.
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    The Social Picture: Advanced Image Analysis Applications
    (The Eurographics Association, 2017) Milotta, Filippo L. M.; Bellocchi, Michele; Battiato, Sebastiano; Andrea Giachetti and Paolo Pingi and Filippo Stanco
    In The Social Picture (TSP) an huge amount of crowdsourced social images can be collected and explored. We distinguish three main kind of events: public, private and cultural heritage related ones. The framework embeds a number of advanced Computer Vision algorithms, able to capture the visual content of images and organize them in a semantic way. In this paper we employ VisualSFM (VSFM) to add new features in TSP through the computation of a 3D sparse reconstruction of a collection within TSP. VisualSFM creates a N-View Match (NVM) file as output. Starting from this NVM file, which characterizes the 3D sparse reconstruction, we are able to build two important relationships: the one between cameras and points and the one between cameras themselves. Using these relationships, we implemented two advanced Image Analysis applications. In the first one, we consider the cameras as nodes in a fully connected graph in which the edges weights are equal to the number of matches between cameras. The spanning tree of this graph is used to explore images in a meaningful way, obtaining a scene summarization. In the second application, we define three kinds of density maps with relation to image features: density map, weighted-density map and social-weighted-density map. Results of a test conducted on a collection from TSP is shown.
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    Stereo-browsing from Calibrated Cameras
    (The Eurographics Association, 2014) Baldacci, Andrea; Ganovelli, Fabio; Corsini, Massimiliano; Scopigno, Roberto; Andrea Giachetti
    Modern Structure-from-Motion (SfM) methods enable the registration of a set of cameras and the reconstruction of the corresponding sparse point cloud of the object/location depicted in the input images. Despite the quality of such techniques they often fail where the input point cloud has a very low density thus decreasing the final user experience. On the other side, modern image-based rendering (IBR) techniques try to avoid a full reconstruction of the geometry by empowering the user with interfaces for the smooth navigation of the acquired images. In such methods, images viewed from viewpoints in-between the actual cameras are generated in some way, for example by using a textured proxy or by warping properly the input images. Usual navigation interfaces, however, neglect to use the inherent nature of such set of cameras which, despite having a wide-baseline, are often well spatially organized as they usually maintain a good overlap between images, varying smoothly both the position and the orientation of the camera. Given such a set of registered cameras, we present a framework for the stereoscopic exploration of the object/location depicted using any type of stereoscopic devices. In the proposed system, the users can have a full tridimensional experience without the need of a complete 3D reconstruction. Our method starts by building a graph where each node is associated to a calibrated camera that represents a virtual eye. Two virtual eyes give a stereo pair. Along each edge of this graph we can instantiate a novel virtual camera using simple linear interpolation of the extrinsic parameters and we can generate its corresponding novel view by using known IBR techniques. This, in practice, extends the domain of the possible views from the discrete set of acquired cameras to a continuous domain given by our graph. Combining any couple of cameras that we can pick on this graph we obtain the set of all possible stereo pairs, that is the codomain of our graph. We give a formal definition of this space, that we called StereoSpace. Built on this, we designed our prototype system for the stereoscopic exploration of photo collections.
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    Design and Fabrication of Grid-shells Mockups
    (The Eurographics Association, 2016) Tonelli, Davide; Pietroni, Nico; Cignoni, Paolo; Scopigno, Roberto; Giovanni Pintore and Filippo Stanco
    Statics Aware Voronoi Grid-shells have been recently introduced in the Architectural Geometry field. These are innovative gridshells endowed with a polygonal topology, whose geometry is structurally optimized by means of a novel algorithm [PTP+15]. Although being structurally effective as proved in [TPP+16] and arguably aesthetically charming, so far these grid-shells have struggled to attract architects' interest. We propose a method to fabricate a mockup of the grid shell by using modern additive 3D printing and laser cutting technologies. We also show how the realised mockup can be used to perform a preliminary validation of the simulated static performances of the grid-shell structure.