Binary shape coding using baseline-based method

Here, we propose a new shape-coding algorithm called baseline-based binary shape coding (BBSC), where the outer or inner contours of an arbitrarily shaped object are represented by traced one-dimensional (1-D) data from the baseline with turning points (TP's). There are two coding modes, i.e., the intra and inter modes as in texture coding. In the intra mode, the differential values of the neighboring 1-D distance values and TP's corresponding to the given shape are encoded by the entropy coder. In the inter mode, object identification, global shape matching, and local contour matching are employed for motion compensation/estimation. Lossy shape coding is enabled by variable sampling in each contour segment or by allowing some predefined error when performing motion compensation. We compare the proposed method with the bitmap-based method of context-based arithmetic encoding (CAE). Simulation results show that the proposed method is better than CAE in coding efficiency for intra mode and better in subjective quality for both intra and inter modes, although the CAE method has performed better than the proposed method in inter mode. Index Terms - Baseline, binary shape coding, block-based method, contour-based method, distance list, MPEG-4, turning point, variable sampling.