Image flow field detection

In this paper, we suggest that the flow field should be smooth over the image, but in terms of its direction rather than its magnitude. A new smoothness constraint, on the image change direction, is proposed. An algorithm employing a multi-scale modification strategy with the proposed smoothness constraint used as a regularization term in an optimisation procedure is presented and used to estimate the image flow field. Experimental results show the algorithm to be efficient in dealing with both image expansion and discontinuous visible surfaces.