Joint Trilateral Filtering for Depth Map Compression New data formats including 2D video and the corresponding depth maps enable new video applications in which virtual views can be rendered, such as 3DTV and freeviewpoint video (FVV). Different from video frames, depth maps typically consist of homogeneous areas (with no textures) separated by sharp edges representing depth value changes such as between foreground and background. Conventional video coding techniques with transforms followed by quantization typically result in large artifacts along such sharp edges. To suppress these coding artifacts while preserving edges, we propose in this paper a novel filtering method for depth coding, joint trilateral filter. The main contribution in the proposed filter design is the utilization of edge information in the collocated video frame as well as in the depth map. The filtering weights are determined by the following three factors: a domain (spatial) filter which measures the proximity of pixel positions, and two range filters. One range filter takes into account the similarity among depth samples and the other one considers the similarity among the collocated pixels in the video frame. By replacing the deblocking filter in H.264AVC with the proposed trilateral filter, simulation results demonstrate up to 0.8 dB gain in rendering quality at given bitrate for depth signal.

An Improved Depth Map Estimation Algorithm For View Synthesis and Multiview Video Coding In this paper, an improved algorithm to generate a smooth and accurate depth map for view synthesis and multiview video coding is developed. For each block in the target view, the algorithm first uses epipolar geometry to find its matched block in the reference view, from which an initial depth is obtained using the triangulation method and depth projection. 3D warping is then applied to refine the depth. In addition, a structural similarity and maximum likelihoodbased approach is developed to fuse the depth estimations from multiple references. Finally, the depth map is smoothed via segmentation and plane fitting. Compared to existing 3D warpingbased depth estimation, the proposed algorithm can achieve up to 4 dB improvement in view synthesis, while requires much fewer bits to encode the depth map. Experimental results in multiview video coding show that the proposed method can outperform the H.264 JMVC software by more than 1 dB.