Purpose. Spillmann and Kurtenbach (ECVP '95) observed that during head rotation a field of contrast-reversing flickering random dots on a stationary monitor appeared to move in the same direction as the head movement. We found that a similar effect occurred in a contrast-reversing checkerboard pattern, and that the effect remained, but was somewhat reduced with fixation. We hypothesized that the displacement of display's frame relative to the head would be a critical factor for the effect. The effect of the vestibulo-ocular reflex (VOR) should also be considered. To examine these factors, we used a head-mounted display (HMD), and compared with-fixation and without-conditions. Methods. Subjects wore the HMD (VF: 48°-width and 40°-height). The contrast-reversing checkerboard pattern was presented to the left eye, while the right eye was occluded. Temporal (from 10 to 30-Hz) and spatial (from 0.01 to 0.05-cpd) frequencies of the pattern were varied. Subjects judged the direction of the perceived motion of the pattern and performed magnitude estimation on the strength of motion while rotating their head around the vertical axis. In some trials, they fixated at a point on the HMD to suppress the VOR. In others, there was no fixation point. Results. Under all conditions, subjects perceived motion of the pattern in the opposite direction to their head movement. The effect was stronger in the without-fixation condition than in the with-fixation condition. With fixation, the strength of the motion perception increased with increasing temporal and spatial frequencies. Without fixation, however, there was no dependency on spatial frequency. Conclusions. Compared with the observation by Spillmann and Kurtenbach, these results suggest that the displacement of display's frame relative to the head affects the direction of the head-induced illusory motion. The VOR itself could not cause these effects, but enhance the motion perception, especially at low spatial frequencies.
|ジャーナル||Investigative Ophthalmology and Visual Science|
|出版ステータス||Published - 1996 2月 15|
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