FINDING POINT CORRESPONDENCES IN MOTION SEQUENCES PRESERVING AFFINE STRUCTURE

In this paper the problem of computing the point correspondences in a sequence of time-varying images of a 3D object undergoing nonrigid (af fine) motion is addressed. It is assumed that the images are obtained through affine projections. The correspondences are established only f rom the analysis of the unknown 3D affine structure of the object, wit hout making use of any attributes of the feature points. It is shown t hat it is possible to establish the point correspondences uniquely (up to symmetry) in the sense that they yield a unique affine structure o f the object and that the computation is possible in polynomial time. Two different algorithms for computing the point correspondences are p resented, Results on various real image sequences, including a sequenc e containing independently moving objects, demonstrate the applicabili ty of the structure based approach to motion correspondence. (C) 1997 Academic Press.