Abstract
This paper proposes an extraction method of the motion of edges using the virtual gradient which is assumed to be around the edges. This method produces linear virtual intensity without any noise along the edges, and it introduces a constraint equation of gradient method to the edges of the time varying images. The optical flow can be extracted fastly by this method. We examined the accuracy of the virtual gradient method by use of simulation images. And we show the validity of this method through experimentations by use of the actual time varying images.