View Synthesis Distortion Estimation With a Graphical Model and Recursive Calculation of Probability Distribution

Depth-image-based rendering (DIBR) is frequently used in multiview video applications such as free-viewpoint television. In this paper, we consider the two DIBR algorithms used in the Moving Picture Experts Group view synthesis reference software, and develop a scheme for the encoder to estimate the distortion of the synthesized virtual view at the decoder when the reference texture and depth sequences experience transmission errors such as packet loss. We first develop a graphical model to analyze how random errors in the reference depth image affect the synthesized virtual view. The warping competition rule adopted in the DIBR algorithms is explicitly represented by the graphical model. We then consider the case where packet loss occurs to both the encoded texture and depth images during transmission and develop a recursive optimal distribution estimation (RODE) method to calculate the per-pixel texture and depth probability distributions in each frame of the reference views. The RODE is then integrated with the graphical model method to estimate the distortion in the synthesized view caused by packet loss. Experimental results verify the accuracy of the graphical model method, the RODE, and the combined estimation scheme.