Residual coding of depth map with transform skipping

Since advanced 3D video systems employ depth information to support free-viewpoint navigation and comfortable 3D video viewing, efficient depth map coding is necessary for future 3D video systems. Most residual data in depth map coding are generated along abrupt depth discontinuities, represented by near-zero and high-magnitude values. In this paper, we model the residual data with two representative values calculated by the K-means clustering method and send them to the decoder by skipping transformation. After best mode decision, we applied the proposed method to a block containing residual data, and then we send the quantized representative values to decoder if its coding rate is less than the conventional best mode. By conducting INTRA only coding, -20.32% bit saving was achieved.