A Curvature-Based Approach to Contour Motion Estimation

We present a novel method of velocity eld estimation for points on moving contours in an image sequence. The method determines the corresponding point in the next image frame by considering curvature changes at each point on a contour. In previous methods, there are errors in estimation for the points which have low curvature variations since those methods compute the solutions by approximating the normal component of optical ow. The proposed method computes optical ow vectors of contour points by minimizing the curvature changes. As a rst step, snakes are used to locate smooth curves in 2-D imagery. Then, the extracted curves are tracked continuously. We excluded the rearranging process in snakes and allowed the snaxel distance to vary. Each point on a contour has a unique corresponding point in the next frame. Experimental results showed that the proposed method computes accurate optical ow vectors for various moving contours.