A new mode selection technique for coding Depth maps of 3D video

Compression of Depth maps that are used in 3D video systems based on Depth Image Based Rendering (DIBR) poses a new challenge in video coding, since it is not a sequence of images for final viewing by end users rather an aid for rendering. Therefore, compressing depth maps using existing video coding techniques yields unacceptable distortions while rendering virtual views. In this paper we propose a novel mode selection method for offline compression of depth maps by selecting modes collaboratively considering an entire row of macroblocks together. For selecting these modes while encoding, we propose a novel distortion criteria that incorporates rendering distortions instead of distortion of depth map itself. A genetic algorithm based optimization technique is used for the mode selection. The simulation results suggest that the proposed technique can improve the PSNR up to 1.6dB in the rendered stereoscopic views in comparison to the block wise mode selection method based on Lagrange Optimization and the distortion of the depth map itself.