Spatio-temporal tuning of motion coherence detection at different luminance levels
Spatio-temporal tuning of motion coherence detection at different luminance levels
复制标题
不同亮度水平下运动相干检测的时空调整
DOI：
10.1016/s0042-6989(01)00265-6
复制
发表时间：
2002
期刊：
影响因子：
1.8
通讯作者：
W.A van de Grind
中科院分区：
文献类型：
--
作者：
M. Lankheet;A.J van Doorn;W.A van de Grind
研究了暗适应对运动相干检测时空调谐的影响。我们比较了两种适应水平下移动随机像素阵列（RPAs）的步长和延迟调整，一种适应光（50 cd/m2），另一种适应相对较暗（0.05 cd/m2）。为了研究相干性检测而不是对比度检测，在每个亮度水平下对RPA进行缩放以进行相等的对比度检测，并使用信噪比范式，其中RPA始终处于固定的超阈值对比度水平。噪声由一个时空不相干的RPA组成，并逐像素地添加到移动的RPA中。使用单步模式寿命刺激测量相干检测的空间和时间限制，其中交替帧上的模式形成一个相干步骤并被刷新。因此，刺激只包含步长和延迟的单一组合的相干运动。暗适应的主要影响是步长偏移较大，略小于保持相同对比度灵敏度所需的空间尺度调整。在光适应水平上，尺度刺激的偏好步长也发生了类似的变化，这表明空间效应与暗适应没有直接联系，而更普遍地与可获得的低水平空间信息的变化有关。黑暗适应将时间调谐改变了大约2倍。长延迟在低亮度水平下更有效，而短延迟不再支持运动相干检测。亮度不变的速度调整曲线，如先前报道的[Lankheet， m.j.m., van Doorn, a.j., Bouman, m.a., and van de Grind， W.A.（2000）运动相干检测作为人类中央视觉亮度的函数。[j] .视觉科学与技术，2016,36(2):1 - 8。
We studied effects of dark adaptation on spatial and temporal tuning for motion coherence detection. We compared tuning for step size and delay for moving random pixel arrays (RPAs) at two adaptation levels, one light adapted (50 cd/m2) and the other relatively dark adapted (0.05 cd/m2). To study coherence detection rather than contrast detection, RPAs were scaled for equal contrast detection at each luminance level, and a signal-to-noise ratio paradigm was used in which the RPA is always at a fixed, supra-threshold contrast level. The noise consists of a spatio-temporally incoherent RPA added to the moving RPA on a pixel-by-pixel basis. Spatial and temporal limits for coherence detection were measured using a single step pattern lifetime stimulus, in which patterns on alternate frames make a coherent step and are being refreshed. Therefore, the stimulus contains coherent motion at a single combination of step size and delay only. The main effect of dark adaptation is a large shift in step size, slightly less than the adjustment of spatial scale required for maintaining equal contrast sensitivity. A similar change of preferred step size occurs also for scaled stimuli at a light-adapted level, indicating that the spatial effect is not directly linked to dark adaptation, but more generally related to changes in the available low-level spatial information. Dark-adaptation shifts temporal tuning by about a factor of 2. Long delays are more effective at low luminance levels, whereas short delays no longer support motion coherence detection. Luminance-invariant velocity tuning curves, as reported previously [Lankheet, M.J.M., van Doorn, A.J., Bouman, M.A., & van de Grind, W.A. (2000) Motion coherence detection as a function of luminance in human central vision. Vision Research, 40, 3599–3611], result from recruitment of different sets of motion detectors, and an adjustment of their temporal properties.