Dae-Sung Cho

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 (l-D) data from the baseline with turning points (TPs). 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 TPs 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.

Binary shape coding using 1-D distance values from baseline

Here we describe a baseline-based binary shape coding method in which an arbitrarily shaped object is represented by the traced 1-D data from the baseline and turning point (TP). The shape coding is performed based on contour-based method in each separated shape. There are two coding modes in shape coding, i.e. the intra and inter mode as in texture coding. In inter coding mode, object identification, global shape matching, and local contour matching are used. In intra mode and residue coding, the DPCM values of TP and the 1-D distance values of the shape are encoded by a fixed arithmetic encoder. Simulation results show that the proposed method has a better coding efficiency and subjective quality compared with the block-based method, i.e. context arithmetic encoding (CAE).

Scan interleaving based scalable binary shape coding

Abstract In this paper, we propose scan interleaving based shape coding (SISC) as a spatial scalable coding algorithm for binary shape. A typical scalable video system has two or more scalable layers. These are the base layer and the associated enhancement layers. In the proposed spatial scalable binary shape coding algorithm, scan interleaving based data encoding (SI) scheme is proposed for the enhancement layer coding. And context-based arithmetic encoding (CAE) method is employed for entropy coding of binary shape data in each scalable layer. SI scheme efficiently exploits the spatial redundancy of the scalable layers. For reducing the temporal redundancy, inter-frame coding based on motion compensation is employed. The major advantages of SISC are high coding gain, low complexity, and consistency with MPEG-4 non-scalable binary shape coding. High coding gain is achieved from the method of coded-scan-line data analysis, which uses exclusive-OR operation on top and bottom reference pixels. Furthermore, by referring the lower layer motion vectors for its inter-frame coding process, SISC also saves some computational overhead of enhancement layer coding. The proposed technique is, currently, adopted in the Working Draft of MPEG-4 Version 2. SISC supports both the frame-based coding mode and the block-based coding mode. The block-based SISC, as in MPEG-4, is mainly described in this paper.