Estimation of velocity vectors from a video stream using discontinuity of optical flow

In computer vision, estimation of the motion of objects has a wide range of applications, such as machine vision and on-board camera systems. The motion in 2D or 3D is observed as a 2D vector, called an optical flow. An optical flow is extracted under a linear constraint between flow vectors and time-space derivations of an image. This constraint (optical flow constraint, OFC) requires the assumption of a linear change of the intensity. On the other hand, the motion is most notably visible as a movement of the edge, but the intensity around the edge cannot be approximated linearly. Therefore, such a simple optical flow is not reliable in the edge which reflects the motion noticeably. We therefore used the OFC of edges proposed by M. Muikaichi and N. Hamada (1999) to extract more precisely the flow of edges and to estimate the motion of the object using these flows.