Competing motion signals compromise to discrete perception
Competing motion signals compromise to discrete perception
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竞争运动信号损害离散感知
作者：
Nakayama;R.;Motoyoshi;I.;and Sato;T.
在自然场景中，物体作为整体的运动通常与物体内包含的局部图案的运动一致。我们研究了人类视觉运动感知的情况下，这些运动相互冲突，通过使用一个Gabor模式的高斯空间窗口和载体光栅移动不一致的不同方向和/或速度。我们发现，当空间窗口不断移动，而载体光栅保持静止或在相反的方向漂移，整个刺激似乎只是间歇性地移动。当载波时间频率（相对于窗口）为4- 8Hz，空间频率为0.5- 1c/deg时，观察到这种间歇性跳跃运动最强烈。即使当观察者跟踪移动的空间窗口时，也获得了类似的数据，这表明错觉基本上是在空间位置坐标处确定的。跳跃的表观时间速率与光栅的时间频率成比例地增加，范围从4到10 Hz。因此，错觉不是由固定的内部时钟决定的。当空间窗口被尖锐的亮度边缘包围时，这种错觉就会减弱。这种跳跃运动可能来自于对高斯窗口的位置表示的重置，而高斯窗口的位置表示只是间歇性地发生。视觉系统容忍由亮度清楚地确定的载体光栅的位置信息与仅由二阶运动（对比度定义的）边缘模糊地确定的高斯窗口的位置信息之间的差异，并且当累积的差异变得超过一定限度时，窗口的位置表示被重置。
In natural scenes, motion of an object as a whole is usually consistent with motion of local patterns contained within the object. We investigated human visual motion perception in cases where these motions conflict with each other, by using a Gabor pattern whose Gaussian spatial window and carrier grating moved inconsistently with different directions and/or speeds. We found that when spatial window moved constantly whereas the carrier grating stayed still or drifted in the opposite direction, the whole stimulus appeared to move only intermittently. This intermittent jumping motion was most strongly observed when carrier temporal frequency (relative to the window) was 4-8 Hz, and spatial frequency was 0.5-1 c/deg. The similar data was obtained even when the observer tracked the moving spatial window, indicating that the illusion is fundamentally determined at the spatiotopic coordinate. The apparent temporal rate of the jumping increased proportionally with the temporal frequency of the grating for a range from 4 to 10 Hz. Thus, the illusion is not determined by a fixed internal clock. The illusion diminished when the spatial window was surrounded by a sharp luminance edge. This jumping motion probably comes from resetting the positional representation of Gaussian window that occurs only intermittently. The visual system tolerates the discrepancy between the positional information of carrier grating determined clearly by luminance and that of Gaussian window determined only vaguely by a second-order motion (contrast defined) edge, and when the accumulated discrepancy becomes beyond certain limit, the positional representation of window is reset.