Subjective evaluation of visual fatigue due to misalignment of motion and still images in a stereoscopic display

In this paper, the relative influences of misalignment such as cross-talk, vertical shift, and motion blur on visual fatigue by using a binocular stereoscopic display has been verified. Experiments were conducted for two cases: a still image and a motion image. They were evaluated by using the simulator sickness questionnaire (SSQ). By changing the disparity angle, cross-talk, and vertical shift in the still-image experiment, it was found that the SSQ score of each parameter increased as the amount of each factor increased. With a two-sample t-test between the presence and absence of each factor, a significant difference was found for the case of a more than 36-arcmin disparity, more than 20% cross-talk, and more than 10% vertical shift. In the motion-image experiment, in which motion speed and the misalignment were varied, it was found that movement of the disparity angle caused much more visual fatigue in comparison with the misalignment factors, which were cross-talk and vertical shift. In contrast, motion images in addition to the cross-talk and/or vertical shift had a slight but unnoticeable relationship to an increase in visual fatigue. Therefore, it was concluded that vertical shift dominated the evaluation for still images, and the movement itself dominated the evaluation for motion images. The results suggest that it is necessary to evaluate visual fatigue according to the representing case, still or motion images, of a 3-D stereoscopic display.