Computing a View Frustum to Maximize an Object's Image Area

Abstract

This paper presents a method to compute a view frustum for a threedimensional object viewed from a given viewpoint, such that the object is completely enclosed in the frustum and the object's image area is also near-maximal in the given two-dimensional rectangular viewing region. This optimization can be used to improve the resolution of shadow and texture maps for projective texture mapping. Instead of doing the optimization in three-dimensional space to find a good view frustum, our method uses a two-dimensional approach. The basic idea of our approach is as follows. First, from the given viewpoint, a conveniently computed view frustum is used to project the three-dimensional vertices of the object to their corresponding two-dimensional image points. A tight two-dimensional bounding quadrilateral is then computed to enclose these two-dimensional image points. Next, considering the project ive warp between the bounding quadrilateral and the rectangular viewing region, our method applies a technique of camera calibration to compute a new view frustum that generates an image that covers the viewing region as much as possible.