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Item Adaptive Clipping of Splats to Models with Sharp Features(The Eurographics Association, 2014) Ivo, Rafael; Ganovelli, Fabio; Vidal, Creto; Scopigno, Roberto; Andrea GiachettiSplat-based models are a good representation because of its absense of topology, making complex modeling operations easier, but keeping the same approximation ratio from triangular meshes. However corners cannot be properly represented by splats without clipping them. We present a new method for clipping splats in models with sharp features. Each splat is an ellipse equipped with a few parameters that allow to define how the ellipse can be clipped against a bidimensional rational Bézier curve and thus it can be used for all those surfaces that show a large number of edge features and different sampling rate around them. The simple and uniform data used to define the clipping curve makes easy the implementation in GPU. We designed and implemented an automatic computation of the clipping curves and a pipeline for sampling a generic surface with splats and render it. In this paper we show how this technique outperforms the previous clipping techniques in precision for objects such as mechanical parts and CAD- like models keeping the rendering speed.Item Stereo-browsing from Calibrated Cameras(The Eurographics Association, 2014) Baldacci, Andrea; Ganovelli, Fabio; Corsini, Massimiliano; Scopigno, Roberto; Andrea GiachettiModern 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.