Novel distortion metric for depth coding of 3D video

In state-of-the-art HEVC-based 3D video codec, multiview video plus associated depth maps are used. In order to achieve better coding performance, instead of the conventional sum of squared errors (SSE), view synthesis optimization (VSO) is proposed and included in the anchor encoder software to calculate view synthesis distortion in rate-distortion optimization (RDO) of depth coding. The anchor VSO achieves high rate-distortion (RD) performance. However, it requires partial rendering and is quite complex and time-consuming. On the other hand, simple SSE metric is fast but RD performance is low. In this paper, we propose a new distortion metric to be used in RDO for depth coding. The complexity of the proposed method is slightly higher than SSE, while its RD performance remains competitive. With a good trade-off between complexity and performance, the proposed method can replace the conventional SSE metric in RDO for depth coding, and can be used as a low-complexity alternative to the anchor VSO.