Early vision and the minimum norm constraint

Contour-based optical flow is used as a working example to show that the Euler-Lagrange equations admit multiple solutions. The minimum norm constraint is presented as a way of overcoming this problem. This constraint is motivated by the minimum norm solution obtained by the use of singular value decomposition for singular problems of signal processing. Some experimental results obtained using the minimum norm constraint are presented. They show how this constraint helps explain the nonrigid interpretation of some rigidly translating contours