Content adaptive in-loop depth map filter for HEVC based 3DV coding

In this paper, a content adaptive in-loop depth map filter is proposed for HEVC based 3DV video coding to improve the quality of the synthesized views. The proposed depth map filtering scheme is block based by reusing the TU (transform unit) split structure in HEVC. Firstly, TU are classified into 3 categories: flat, directional, and textureless, according to the characteristics of the depth map. Then four kinds of filters are designed by considering the characteristics of the current TU and neighbor TUs jointly. The proposed scheme is incorporated into HTM3.0- the reference software of HEVC based 3D video coding. The experimental results show both subjective and objective quality improvement. The average BD-rate reduction is 0.65% for synthesis views in HD test sequences, and the maximum BD-rate reduction is up to 1.6%.