Tuned sparse depth map coding using redundant predefined transform domain

Multiview video plus depth is the most popular 3D video representation that would support novel applications including free viewpoint television. These applications highly depend on high quality rendering of interpolated views which, as well, highly depends on the quality of decoded depth images. Therefore, a depth map coding that preserves perceptual quality, particularly on high frequency regions, is primary. In this paper, we propose a coding depth maps method that deals with emerging sparse signal decomposition technique. Depth images are approximated by a linear combination of few nonzero coefficients and dictionary atoms. Selected atoms are elementary signals based on a mixture of discrete cosine and B-splines of first degree. Sparse depth maps coding is tuned using a couple quality criterion such that depth discontinuities are preserved. The results investigated by objective evaluations over several depth maps imply that the proposed depth maps coding achieves better Rate-Distortion than JPEG and JPEG 2000. Subjective evaluation is also presented to stress the visual quality of interpolated views.