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This paper proposes a novel stereovision framework for multi-view 3D reconstruction relying on inputs of both several sets of multi-baseline views and a visual hull [3]. The pipeline is illustrated in figure 1. Our Contributions of this paper are threefold: (i) improvement of our multi-baseline stereovision method [2] by VH guidance, (ii) carving VH from stereovision surface and (iii) merging differently carved volumes. Our approach builds on a previously proposed framework [2] for multi-baseline stereo-vision which provides upon the Disparity Space (DS) introduced by [5], a materiality map expressing the probability for 3D sample points to lie on a visible surface. Our acquisition system [4] composed of the cameras which are scattered around the observed scene in order to build the VH, with several groups laid as multi-scopic units dedicated to multi-baseline stereovision. Multi-scopic units are composed of aligned and evenly distributed cameras.

We describe the development and evaluation of a large-scale multimodal virtual reality simulation suitable for the visualization of cultural heritage sites and architectural planning. The system is demonstrated with a reconstruction of an ancient Greek temple in Messene that was created as part of a EU funded cultural heritage project (CREATE). The system utilizes a CAVE-like theatre consisting of head-tracked user localization, a haptic interface with two arms, and 3D sound. The haptic interface was coupled with a realistic physics engine allowing users to experience and fully appreciate the effort involved in the construction of architectural components and their changes through the ages. Initial user-based studies were carried out, to evaluate the usability and performance of the system. A simple task of stacking blocks was used to compare errors and timing in a haptics-enabled system with a haptics-disabled system. In addition, a qualitative study of the final system took place while it was installed in a museum.

In this paper, we address the problem of shadow computation for large environments including thousands of dynamic objects. The method we propose is based on the assumption that the environment is 2.5D, which is often the case for virtual cities, thus avoiding complex visibility computation. We apply our method for virtual cities populated by thousands of walking humans, which we render with impostors, allowing real time simulation.In this paper, we treat the cases of shadows cast by buildings on humans, and by humans on the ground. To avoid 3D computation, we represent the shadows cast by buildings onto the environment with a 2.5D shadow map. When humans move, we quickly access the shadow information at the current location with a 2D grid. For each new position of a human, we compute its coverage by the shadow, and we render the shadow on top of the impostor with low cost using multi-texturing hardware. We also use the property of an impostor to display the shadow of humans on the ground plane, by projecting the impostor relatively to the light source.The method is currently limited to sharp shadows and a single light source. However approximations could be made to allow non-accurate soft-shadows. We show in the results that the computation of the shadows, as well as the display is done in real time, and that the method could be easily extended to real time moving light sources.