Efficient perspective-accurate silhouette computation and applications

Silhouettes are perceptually and geometrically salient features of geo metric models. Hence a number of graphics and visualization applications need to find them to aid further processing. The efficient computation of silhouettes, especially in the context of perspective projection, is known to be difficult. This paper presents a novel efficient and practical algorithm to compute silhouettes from a sequence of viewpoints under perspective projection. Parallel projection is a special case of this algorithm. Our approach is based on a point-plane duality in three dimensions, which allows an efficient computation of the \emph{changes} in the silhouette of a polygonal model between consecutive frames. In addition, we present several applications of our technique to problems from computer graphics and medical visualization. We also provide experimental data that show the efficiency of our approach. million vertices on an SGI Onyx workstation.