Shape skeletonization by identifying discrete local symmetries

This paper presents a new skeletonization method based on a novel concept-discrete local symmetry. A skeleton obtained from discrete local symmetries approaches the skeleton of the underlying continous shape if the sampling is dense enough. Discrete local symmetries can be obtained by computing the constrained Delaunay triangulation of the underlying image. Internal triangles of a triangulation are divided into isolated triangles, end triangles, normal triangles and junction triangles. A discrete local symmetry corresponds to an isolated triangle, or an end triangle, or a normal triangle. Several measures are taken to remove skeletonization artifacts and suppress image noise. The proposed method can produce correct centre lines and junctions. It is efficient and robust against noise. The method is suitable for skeletonizing high-resolution images.