文档介绍：chain codes Chapter 4 Representation & Description Chain codes are used to represent a boundary by a connected sequence of straight-line segments of specified length and direction. Typically, this representation is based on 4- and 8-connectivity of the segments. Chapter 4 Representation & Description Polygonal approximations Signature There are three types of polygonal approximations: Minimum perimeter polygons Merging techniques Splitting techniques Signatures are 1-D functional description of a boundary and may be generated in various ways. One of the simplest is to plot the distance from the centroid to the boundary as a function of angle. Chapter 4 Representation & Description Chapter 4 Representation & Description Euler number E=C-H Where H is the number of holes and C is the ponents i