Coding efficiency of multiring differential chain coding (line drawing transmission)

A new coding scheme for line drawings, multiring differential chain coding (MRDCC) is introduced, based on relative vectors drawn from multiple coding rings. The performance of MRDCC depends on the probability distribution of the different rings included in the code. A model is presented for the evaluation of ring probabilities; these have been used, together with the corresponding relative vector probabilities, to obtain the coding rate. Compared to the standard chain code (SCC), generalised chain code (GCC) and differential chain code (DCC), MRDCC is expected to reduce the coding rate by 40%, 53% and 13%, respectively. Experiments performed show an average reduction in coding rate by 50%, 23% and 5% compared to SCC, GCC and DCC, respectively.<>