Computation of coherent optical flow by using multiple constraints

The optical flow constitutes one of the most widely adopted representations to define and characterize the evolution of image features over time. In order to compute the velocity field, it is necessary to define a set of constraints on the temporal change of image features. We consider the implications in using multiple constraints arising from multiple data points. The first step is the analysis of differential constraints and how they can be applied, locally, to compute the image velocity. This analysis allows to relate each constraint to a particular gray level pattern. This approach is extended to multiple image points, allowing also the characterization of the temporal behaviour of the image features and to detect erroneous measurements due to occlusions, depth discontinuities or shadows. Several experiments are presented from real image sequences