Ohtani Y, Ido K, Ejima Y
Department of Liberal Arts and Sciences, Faculty of Engineering, Toyama Prefectural University, Japan.
Vision Res. 1995 Aug;35(16):2277-86. doi: 10.1016/0042-6989(94)00315-d.
When a sinusoidal (test) grating is displaced horizontally by a phase angle of 180 deg in a two-frame apparent motion display, the perceived direction of motion is ambiguous; the test grating appears to move either to the left or to the right (or to both directions). On the other hand, when the test grating is displaced by 180 deg synchronously with the inducing gratings which, presented above and below the test grating, jump unambiguously in one direction (e.g. displaced by 90 deg), the test grating always appears to move in the same direction as the inducing gratings (motion assimilation). In the present study, the effects of luminance contrast and phase difference on motion assimilation were examined. The proportion of perceived direction of motion (left or right) was measured as a function of phase difference between the test grating in the first and the second frame. The magnitude of motion assimilation was evaluated as the change in the phase difference for which the proportions of observers' response were equal (50%) for both directions. The magnitude of motion assimilation increased with increase in the contrast of the inducing gratings or with decrease in the contrast of the test grating. Also, the magnitude increased as the phase difference of the inducing gratings departed from 180 deg. Based on these results, a quantitative formulation between the magnitude of motion assimilation, and the contrast and the phase difference of the stimulus gratings was derived. Further, a model was proposed which explains the stimulus dependences of motion assimilation in terms of response-integration among local motion detectors.
在双帧表观运动显示中，当一个正弦（测试）光栅在水平方向上位移180度相位角时，运动的感知方向是模糊的；测试光栅似乎向左或向右移动（或向两个方向移动）。另一方面，当测试光栅与诱导光栅同步位移180度时，诱导光栅在测试光栅的上方和下方呈现，明确地向一个方向跳跃（例如位移90度），测试光栅总是似乎与诱导光栅向相同方向移动（运动同化）。在本研究中，研究了亮度对比度和相位差对运动同化的影响。测量了运动感知方向（左或右）的比例作为第一帧和第二帧中测试光栅之间相位差的函数。运动同化的幅度被评估为观察者对两个方向的反应比例相等（50%）时相位差的变化。运动同化的幅度随着诱导光栅对比度的增加或测试光栅对比度的降低而增加。此外，随着诱导光栅的相位差偏离180度，幅度也会增加。基于这些结果，推导了运动同化幅度与刺激光栅的对比度和相位差之间的定量公式。此外，还提出了一个模型，该模型根据局部运动探测器之间的反应整合来解释运动同化的刺激依赖性。
