Cross-switching in asymmetrical coding for stereoscopic video
Wa James Tam, Lew B. Stelmach, Filippo Speranza, Ronald Renaud · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2002
Asymmetrical coding is a technique that can be used to reduce the bandwidth required for transmission and storage of stereoscopic video images. This technique is based on observations that a high level of perceived stereoscopic image quality can be maintained when the quality of the video stream to one eye is reduced. To address issues surrounding eye dominance and viewing comfort, we proposed to balance the inputs to the two eyes by cross-switching the image quality in the two streams over time. Here, we report two experiments on the visibility of cross-switches, for video sequences and random-dot stereograms. In both experiments, we manipulated a) the degree of asymmetry in quality of the video streams by varying image blur, and b) the timing of the cross-switch (either at a scene-cut or during a continuous scene). The viewers' task was to indicate whether the first of the second of a pair of stereoscopic presentations contained a cross-switch. We found that the cross-switch was masked by a scene cut, and that ease of detection depended on the degree of asymmetrical blur. We conclude that asymmetrical coding combined with cross-switching at scene cuts is a practical bandwidth-reduction technique for stereoscopic video.