Temporal sub-sampling of depth maps indepth image based rendering of stereoscopic image sequences

摘要

In depth image based rendering, video sequences and their associated depth maps are used to render new cameraviewpoints for stereoscopic applications. In this study, we examined the effect of temporal downsampling of thedepth maps on stereoscopic depth quality and visual comfort. The depth maps of four eight-second video sequenceswere temporally downsampled by dropping all frames, except the first, for every 2, 4, or 8 consecutive frames. Thedropped frames were then replaced by the retained frame. Test stereoscopic sequences were generated by using theoriginal image sequences for the left-eye view and the rendered image sequences for the right-eye view. Thedownsampled versions were compared to a reference version with full depth maps that were not downsampled.Based on the data from 21 viewers, ratings of depth quality for the downsampled versions were lower. Importantly,ratings depended on the content characteristics of the stereoscopic video sequences. Results were similar for visualcomfort, except that the differences in ratings between sequences were larger. The present results suggest that moreprocessing, such as interpolation of depth maps, might be required to counter the negative effects of temporaldownsampling, especially beyond a downsampling of two.