A Hybrid Admissible Distortion Checking Algorithm for the B-Spline-Based Operational Rate-Distortion Optimal Shape Coding

Admissible distortion checking algorithm plays a very important role in both rate distortion performance and computational efficiency of B-spline-based operational rate-distortion optimal shape coding framework under the minimum-maximum criterion. Existing distortion measurement using chord-length parameterization (DMCLP) is fast but results in extra bit-rate problem. In contrast, the up to date accurate distortion measurement using analytical model (ADMAM) can achieve the smallest bit-rate but is very time consuming. It motivates us to develop a hybrid admissible checking algorithm that can take full use of each advantage. Recalling the definitions of both DMCLP and ADMAM for each associated contour point, the authors show that DMCLP is the distance from the parameterized B-spline point while ADMAM is the shortest distance from the approximating B-splines.