Walsh G, Charman W N
Department of Ophthalmic Optics, Glasgow College, Scotland.
Vision Res. 1990;30(1):163-73. doi: 10.1016/0042-6989(90)90135-8.
Small periodic (0.25-40 Hz) changes in the contrast of suprathreshold, spatially sinusoidal (0.8-10.5 c/deg) grating test objects were generated on an oscilloscope screen. It was found that the minimum temporal modulation in spatial contrast which could be detected subjectively was approximately proportional to the mean contrast of the grating during the change, provided that the minimal spatial modulation of the grating was above threshold. The contrast increment threshold was dependent on both the grating spatial frequency and the temporal frequency of the modulation: for any fixed temporal frequency in the range 2-8 Hz it increased approximately linearly with spatial frequency; for fixed spatial frequency the threshold was minimal at temporal frequencies of a few Hz. The relevance of these results to the possible role of fast fluctuations in the control of accommodation response is considered.
在示波器屏幕上生成了超阈值、空间正弦（0.8 - 10.5周/度）光栅测试对象对比度的小周期（0.25 - 40赫兹）变化。结果发现，只要光栅的最小空间调制高于阈值，主观上能够检测到的空间对比度的最小时间调制大致与变化期间光栅的平均对比度成正比。对比度增量阈值取决于光栅空间频率和调制的时间频率：对于2 - 8赫兹范围内的任何固定时间频率，它随空间频率大致呈线性增加；对于固定空间频率，阈值在几赫兹的时间频率时最小。本文考虑了这些结果与快速波动在调节反应控制中可能作用的相关性。
