Determining optical flow using a differential method

A comparison of different methods for determining optical flow based on local information is presented. It is shown that to overcome the aperture problem, second order differential terms of the image function are required. It is also argued that the fundamental problem of measuring optical flow is to determine the velocity in as small an aperture as possible. It is concluded that the technique of Lucas and Kanade (see Barren et al., Performance of optical flow techniques, Int. J. Computer Vision, 12 (1) (1994) 43-77) is the best generalised second order method for achieving this objective.