Palmer J, Mobley L A, Teller D Y
Department of Psychology, University of Washington, Seattle 98195.
J Opt Soc Am A. 1993 Jun;10(6):1353-62. doi: 10.1364/josaa.10.001353.
Under some conditions, direction-of-motion thresholds are elevated with respect to detection thresholds for isoluminant chromatic stimuli. In the present study we investigated the effect of small luminance mismatches on ratios of direction-of-motion thresholds to detection thresholds (M/D ratios). The stimuli were 2 deg x 2 deg patches of a moving 1-cycle/deg, 2.75-deg/s sinusoidal grating, modulated spatially in luminance, chromaticity, or both. M/D ratios were close to 1 except when luminance modulation was < 1%, defined with respect to the individual subject's isoluminance point; in this range M/D ratios varied from 1.5 to 4.4. Sets of thresholds for both detection and motion tasks conformed approximately to ellipses. Thus, although motion processing shows a differential loss of sensitivity at isoluminance, similar summation rules appear to apply to the combination of luminance and chromatic signals for both tasks.
在某些条件下，相对于等亮度色刺激的检测阈值，运动方向阈值会升高。在本研究中，我们研究了小亮度失配对运动方向阈值与检测阈值之比（M/D比）的影响。刺激物是一个移动的1周期/度、2.75度/秒的正弦光栅的2度×2度斑块，在亮度、色度或两者上进行空间调制。M/D比接近1，除非亮度调制小于1%（相对于个体受试者的等亮度点定义）；在此范围内，M/D比从1.5变化到4.4。检测和运动任务的阈值集大致符合椭圆。因此，尽管运动处理在等亮度时显示出不同的灵敏度损失，但类似的求和规则似乎适用于这两个任务的亮度和色度信号组合。
