A Computational Geometric Approach to Visual Hulls

Recognizing 3D objects from their 2D silhouettes is a popular topic in computer vision. Object reconstruction can be performed using the volume intersection approach. The visual hull of an object is the best approximation of an object that can be obtained by volume intersection. From the point of view of recognition from silhouettes, the visual hull can not be distinguished from the original object. In this paper, we present eecient algorithms for computing visual hulls. We start with the case of planar gures (polygons and curved objects) and base our approach on an eecient algorithm for computing the visibility graph of planar gures. We present and tackle many topics related to the query of visual hulls and to the recognition of objects equal to their visual hulls. We then move on to the 3-dimensional case and give a avor of how it may be approached.