Estimation of subjective quality for mixed-resolution stereoscopic video

In mixed-resolution (MR) stereoscopic video, one view is presented with a lower resolution compared with the other one; therefore, a lower bitrate, a reduced computational complexity, and a decrease in memory access bandwidth can be expected in coding. The human visual system is known to fuse left and right views in such a way that the perceptual visual quality is closer to that of the higher-resolution view. In this paper, a subjective assessment of mixed resolution (MR) stereoscopic videos is presented and the results are analyzed and compared with previous subjective tests presented in the literature. Three downsampling ratios 1/2, 3/8, and 1/4 were used to create lower-resolution views. Hence, the lower-resolution view had different spatial resolutions in terms of pixels per degree (PPD) for each downsampling ratio. It was discovered that the subjective viewing experience tended to follow a logarithmic function of the spatial resolution of the lower-resolution view measured in PPD. A similar behavior was also found from the results of an earlier experiment. Thus, the results suggest that the presented logarithmic function characterizes the expected viewing experience of MR stereoscopic video.