Digital line segment coding: A new efficient contour coding scheme

A new coding scheme is proposed for two-tone image contours. The basic idea is to detect digital line segments on the contour and code them using fixed- or variable-length codewords; the present work deals mainly with fixed-length codewords. It is demonstrated that the conventional contour run length coding by Freeman´s chain code is a special case of this scheme. The data compressibility of the scheme is studied and the test results on several contours are presented. The results show that the present scheme is superior to the conventional scheme.