Inherently edge-preserving depth-map coding without explicit edge detection and approximation

In emerging 3D video coding, depth has significant importance in view synthesis, scene analysis, and 3D object reconstruction. Depth images can be characterized by sharp edges and smooth large regions. Most of the existing depth coding techniques use intra-coding mode and try to preserve edges explicitly with approximated edge modelling. However, edges can be implicitly preserved as long as the transformation is avoided. In this paper, we have demonstrated that inherent edge preserving encoding of inter-coded block residuals, uniformly quantized at pixel domain using motion data from associated texture components, is more efficient than explicitly edge preserving intra-coding techniques. Experimental results show that the proposed technique have achieved superior image quality of synthesized views against the new 3D-HEVC standard. Lossless applications of the proposed technique has achieved on average 66% and 23% bit-rate savings against 3D-HEVC with negligible quantization and perceptually unnoticeable view synthesis, respectively.