Statistical analyses of disparity maps and disparity compensated residuals in the presence of occlusions

The doubling of the data rate in stereo image systems causes problems for archiving and transmission, and compression is obviously desirable. In general, stereo codecs code one of the views as the reference using a conventional method like MPEG-2 assuming two basic sources, and the disparity map is calculated to aid the coding process. It can be coded using the DCT, another lossy method, or a lossless compression. The other view is either coded directly, or is restored from a combination of the reference view, the disparity data and a residual error image. In transform coding, inappropriate or coarse quantisation may cause coding artifacts. This work analyses and models the distribution of the 2D DCT coefficients of disparity maps and of disparity compensated residuals in the presence of occlusions, highlighting some points that should be considered when going from the monocular to the multiple-camera codec design process