Enhanced view synthesis prediction for coding of non-coplanar 3D video sequences

In many cases, view synthesis prediction (VSP) for 3D video coding suffers from inaccurate depth maps (DMs) caused by non-reliable point correspondences in low textured areas. In addition, occlusion handling is a major issue if prediction is performed from one reference view. In this paper, we address VSP for non-coplanar 3D video sequences modified by a linear DM enhancement model. In this model, points close to edges in the DM are treated as key points, on which depth estimation is assumed to work well. Other points are assumed to have unreliable depth information and the depth is modelled by the solution of the Laplace equation. As another preprocessing stage for DMs, the influence of guided image depthmap filtering is investigated. Moreover, we present an inpainting method for occluded areas, which is based on the solution of the Laplace equation and corresponding depth information. Combining these techniques and applying it to VSP for 3D video sequences, which are captured by an arc-arranged camera array, our approach outperforms state of the art models in coding efficiency. Experimental results show bit rate savings up to 4.3 % compared to HEVC-3D for coding two views and corresponding depth in an All Intra encoder configuration.