Rate-Distortion Optimization for depth map coding with distortion estimation of synthesized view

In 3D video systems, depth maps supply geometry information which is used to generate virtual views. The coding of the depth maps can be improved by considering distortion of synthesized views instead of depth map distortion. Therefore, this paper proposes a novel metric for depth coding, which quantifies the impact of the depth distortion on the fidelity of synthesized views, without banding with any complete rendering process. The metric is integrated into Rate-Distortion Optimization (RDO) process for mode decision in depth map coding, replacing the metric in HTM software. Experimental results show that the proposed metric significantly improves the coding efficiency of 3D video by about 10% bitrate saving compared with conventional RDO. Moreover, the RDO with the proposed metric achieves stable coding efficiency for different decoder-side renderers with low computation complexity.