Rate distortion analysis in a disparity compensated scheme

This paper addresses the problem of rate distortion analysis in the context of multi-view image coding, where images are predicted via disparity compensation based on depth map. We first present an an- alytical model for the variance of the residual error in a predicted frame when the prediction is done with the help of a compressed depth map. This residual variance model presents a convenient ex- pression that separates the different error origins (reference frame quantization, depth map coding, and motion activity). We then val- idate the novel analytical model by testing separately its different underlying hypotheses. Finally, we illustrate an application of our analytical model in a simple bit allocation problem where the ob- jective is to determine the optimal distribution of a global bit bud- get among reference frame, depth map and disparity-compensated frame. We observe that the optimal allocation given by the analyt- ical model corresponds in practice to the best rate distribution for high bitrate, which confirms the potential of the proposed model in the design of rate-controlled multi-view coding algorithms.