Polygonal Approximation of Region Boundaries and Edges
This chapter describes a method of representing curves in two-dimensional digital images as polygons. This kind of curve representation is useful for image analysis because the shape of a polygon can be easily investigated by simple geometrical means such as measuring lengths and angles. Polygonal approximation also suggests a new method of estimating curvature of digital curves. For this purpose a polygon can be replaced by a smooth sequence of circular arcs and straight line segments. Smooth means that each straight segment is the tangent to the previous and the subsequent arc.