ANALYSIS OF OPTICAL-FLOW CONSTRAINTS

Different constraint equations have been proposed in the literature fo r the derivation of optical flow, Despite of the large number of paper s dealing with computational techniques to estimate optical how, only a few authors have investigated conditions under which these constrain ts exactly model the velocity field, that is, the perspective projecti on on the image plane of the true 3-D velocity, In this paper, these c onditions are analyzed under different hypotheses, and the departures of the constraint equations in modeling the velocity field are derived for different motion conditions. Experiments are also presented givin g measures of these departures and of the induced errors in the estima tion of the velocity field.