Optimization of Occlusion-Inducing Depth Pixels in 3-D Video Coding
This work addresses an incremental improvement in 3-D video coding efficiency for applications like virtual reality or video compression, focusing on a specific, overlooked aspect of depth map coding.
The paper tackles the problem of optimizing occlusion-inducing depth pixels in 3-D video coding, which are often neglected due to their minimal impact on synthesized views, by proposing a depth map coding scheme that uses allowable depth distortions to minimize geometry distortion under bit rate constraints, resulting in improved coding efficiency as confirmed by simulations.
The optimization of occlusion-inducing depth pixels in depth map coding has received little attention in the literature, since their associated texture pixels are occluded in the synthesized view and their effect on the synthesized view is considered negligible. However, the occlusion-inducing depth pixels still need to consume the bits to be transmitted, and will induce geometry distortion that inherently exists in the synthesized view. In this paper, we propose an efficient depth map coding scheme specifically for the occlusion-inducing depth pixels by using allowable depth distortions. Firstly, we formulate a problem of minimizing the overall geometry distortion in the occlusion subject to the bit rate constraint, for which the depth distortion is properly adjusted within the set of allowable depth distortions that introduce the same disparity error as the initial depth distortion. Then, we propose a dynamic programming solution to find the optimal depth distortion vector for the occlusion. The proposed algorithm can improve the coding efficiency without alteration of the occlusion order. Simulation results confirm the performance improvement compared to other existing algorithms.