Visual comfort/discomfort and visual fatigue caused by stereoscopic HDTV viewing

The problems associated with watching stereoscopic HDTV have been classified into three groups, one of which is how natural/unnatural stereoscopic pictures look to viewers. It is known that the shooting and viewing conditions affect the depth of a stereoscopic image, and this depth distortion is a major factor influencing the viewer's stereoscopic perception. The second group concerns the visual comfort/discomfort. Visual discomfort is caused by the difficulty of fusing left and right images because of excessive binocular parallax and its temporal changes. We have studied how visual comfort is affected by the range of parallax distribution and temporal parallax changes. The results show that stereoscopic images are comfortable to view for an angular parallax of up to about 60 minutes and that visual comfort is achieved if discontinuous temporal changes are angle of 60 minutes or less. The third group concerns visual fatigue that a viewer experiences after viewing a stereoscopic HDTV program, which is thought to be mainly caused by the mismatch between the eyes' convergence and accommodation. We confirmed that, after observing stereoscopic images for about an hour, the fusion range diminishes and the viewer's visual functions deteriorate as a result.