Modified watershed algorithm considering zero-crossing point of gradient
Dong-In Park, Yun-Ho Ko, Jihong Lee, Young‐Woo Park · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2007
In this paper, we propose a modified watershed algorithm considering zero-point of gradient to obtain a correct edge of a region. The conventional watershed algorithm decide priority considering gradient of a region to be extended. However if the grey levels of two neighboring seeds are quite different, the ridge line obtained by the conventional watershed algorithm is not coincided with the correct edge. It is probable that the point where gray level extreme value occurs will be estimated as an edge of two neighboring regions. Therefore more correct edge of a region can be obtained if the expansion of watershed algorithm is delayed where the extreme value occurs. The position where the gray level extreme value occurs corresponds to the position where the zero-crossing of gradient occurs. So we adjust the priority to postpone expansion at the zero-crossing point of gradient. We compare the proposed method with the conventional method and validate that this proposed method can extract more correct edge of a region.