Time-variable camera separation for compression of stereoscopic video

This paper presents a hypothesis that stereoscopic perception requires a short adjustment period after a scene change before it is fully effective. A compression method based on this hypothesis is proposed - instead of coding pictures from the left and right views conventionally, a view in the middle of the left and right view is coded for a limited period after a scene change. The coded middle view can be utilized in two alternative ways in rendering. First, it can be rendered as such, which causes an abrupt change from conventional monoscopic video to stereoscopic video. Second, the layered depth video (LDV) coding scheme can be used to associate depth, background texture, and background depth to the middle view, enabling view synthesis and gradual view disparity increase in rendering. Subjective experiments were conducted to evaluate and validate the presented hypothesis and compare the two rendering methods. The results indicate that when the maximum disparity between the left and right views was relatively small, the presented time-variable camera separation method was imperceptible. A compression gain, the magnitude of which depended on the scene duration, was achieved with half of the sequences having a suitable disparity for the presented coding method. © 2010 SPIE