Silhouette Mapping

Recent image-based rendering techniques have shown success in approximating detailed models using sampled images over coarser meshes. One limitation of these techniques is that the coarseness of the geometric mesh is apparent in the rough polygonal silhouette of the rendering. In this paper, we present a scheme for accurately capturing the external silhouette of a model in order to clip the approximate geometry. Given a detailed model, silhouettes sampled from a discrete set of viewpoints about the object are collected into a silhouette map. The silhouette from an arbitrary viewpoint is then computed as the interpolation from three nearby viewpoints in the silhouette map. Pairwise silhouette interpolation is based on a visual hull approximation in the epipolar plane. The silhouette map itself is adaptively simplified by removing views whose silhouettes are accurately predicted by interpolation of their neighbors. The model geometry is approximated by a progressive hull construction, and is rendered using projected texture maps. The 3D rendering is clipped to the interpolated silhouette using stencil planes.