Pictures and trails: a new framework for the computation of shape and motion from perspective image sequences

This paper presents a new framework for the computation of shape and motion from a sequence of images taken under perspective projection. The framework is based on two abstractions, the picture and trail loci, that represent respectively the set of all pictures of the same scene and the set of all trails that a point in the world can leave on the image for a given camera trajectory. These abstractions lead to a remarkably clean relation between perspective and orthography. A shape and motion reconstruction method is developed for the case of a two-dimensional world but all concepts also hold in three dimensions. Experiments show that the method is rather immune to noise but critically dependent on camera calibration