Representation of Digitized Contours in Terms of Conic Arcs and Straight-Line Segments

One of the most interesting tasks of scene analysis is the reconstruction problem, which is the problem of finding a three-dimensional description of a scene from two or more projections. When the scene is assumed to be composed of man-made objects bounded by quadric surfaces, the reconstruction process is simplified if the border lines in each projection are given by means of straight-line segments and conic arcs. Since each projection is a digitized picture, a preprocessing stage produces a description of the boundaries in terms of point sequences. This report discusses an algorithm for converting the point-sequence description to an analytic description using conic arcs and straight-line segments.