Shape as a Perturbation to Projective Mapping
Leonard McMillan and Gary Bishop
In the classical computer-graphics approach to three-dimensional rendering, a scene is described in terms of its geometry and surface properties. Given this representation, the rendering task can be thought of as a physical simulation problem. Recently, there has been an increased interest in alternative rendering paradigms, most of which fall into a category that we call image-based rendering. In these alternative approaches, reference images, rather than geometry and surface properties, are used as the primary scene description. In this paper we describe a simple perturbation to projective mapping that describes both arbitrary shape and changes of viewing parameters. We show how this perturbation is related to observable image characteristics such as stereo disparity and optical flow. We also demonstrate how this method can be used as the basis for image-based rendering systems, which operate without any explicit geometric scene description.
Figure 1. Example images output from an image-based rendering system. The input reference image is shown in Image A. Image B shows a perspective mapping. Images C and D show perturbed perspective mappings.