Timevariable camera separation for compression of stereoscopic video This paper presents a hypothesis that stereoscopic perception requires a short adjustment period after a scene change before it is fully effective. A compression method based on this hypothesis is proposed  instead of coding pictures from the left and right views conventionally, a view in the middle of the left and right view is coded for a limited period after a scene change. The coded middle view can be utilized in two alternative ways in rendering. First, it can be rendered as such, which causes an abrupt change from conventional monoscopic video to stereoscopic video. Second, the layered depth video (LDV) coding scheme can be used to associate depth, background texture, and background depth to the middle view, enabling view synthesis and gradual view disparity increase in rendering. Subjective experiments were conducted to evaluate and validate the presented hypothesis and compare the two rendering methods. The results indicate that when the maximum disparity between the left and right views was relatively small, the presented timevariable camera separation method was imperceptible. A compression gain, the magnitude of which depended on the scene duration, was achieved with half of the sequences having a suitable disparity for the presented coding method.

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.