Real-time interactive object outlining using control points and smoothness parameter manipulation

Several promising methods of outlining objects from image have been reported. They, however, do not always give accurate outlines. We construct an interactive outlining method based on the thinning process to achieve accurate, easy, and intuitive outlining for any image. In this method, the region of the band where the outline is allowed to exist is controlled, and the outline curve is edited indirectly by manipulating the smoothing parameter of the filter for the gradient field. In its implementation, the thinning process was made as non-redundant as possible. The outline curve is displayed typically in about 0.2 sec after each interactive operation on a 300 MHz PC.