Skeletons and Segmentationof Shapes

The emphasis of the two approaches described in this chapter is on determining shape skeletons in the presence of noise. The parts of the skeleton which are most robust in the presence of noise correspond to the parts of the shape where its width varies slowly. In contrast, singular points of the skeleton such as junctions tend to be sensitive to noise. The strategy therefore is to concentrate on determining the robust parts and fill in the details afterwards as needed. The first approach takes advantage of the geometry of the distance function while the second analyzes the local symmetries of the level sets of a smooth analog of the distance function.