Contour matching: a curvature-based approach

Abstract

The lack of information about tangential velocity makes velocity estimation erroneous in contour matching. Classical methods use the normal velocity, together with some smoothness constraints, since the tangential velocity cannot be recovered. This paper presents a contour matching method that computes displacements with a criteria of minimum curvature differences. The first derivative of tangential velocity is available from the image intensities and is related to the contour curvature. We compute the velocities using the curvature as well as the normal component. Consequently, the estimation error due to the tangential component is reduced substantially. A contour having occluding parts leads to mismatching. Our method determines occluding parts before the contour matching by analyzing the change of curvature distribution. Experimental results showed that the proposed method computes accurate velocity vectors for various moving contours. (C) 1998 Elsevier Science B.V.