Improving the Accuracy of Diierential{based Optical Flow Algorithms

This work deals with the design of the low{level stages of any diierential{ based optical ow algorithm. The problem is the accurate estimaton of the spatio{temporal derivatives of the moving image, to be used in the solution of the gradient constraint equation. We claim that the \tradi-tional" techniques for the partial derivatives estimation can be improved by i) exploiting all the information provided by both elds within a frame in the case of interlaced scanning systems, ii) adopting prolate spheroidal lters instead of gaussian lters in order to get rid of noise and alias-ing, and iii) using larger size diierentiators, designed by a weighted least squares technique.