Rovamo J M, Kankaanpää M I, Hallikainen J
Department of Optometry and Vision Sciences, Cardiff University, King Edward VII, Cathays Park, CF10 3NB Cardiff, Wales, UK.
Vision Res. 2001 Jun;41(13):1659-67. doi: 10.1016/s0042-6989(01)00036-0.
To determine the spatial modulation transfer function (MTF) of the human foveal visual system for equiluminous chromatic gratings we measured contrast sensitivity as a function of retinal illuminance for spatial frequencies of 0.125-4 c/deg with equiluminous red-green and blue-yellow gratings. Contrast sensitivity for chromatic gratings first increased with luminance, obeying the Rose-DeVries law, but then the increase saturated and contrast sensitivity became independent of light level, obeying Weber's law. Critical retinal illuminance (I(c)) marking the transition point between the laws was found to be independent of spatial frequency at 165 phot. td. According to our detection model of human spatial vision the MTF of the retina and subsequent neural visual pathways (P(c)) is directly proportional to radicalI(c). Hence, P(c) is independent of spatial frequency, reflecting the lack of precortical lateral inhibition for equiluminous chromatic stimuli in spatiochromatically opponent retinal ganglion cells and dLGN neurons.
为了确定人中央凹视觉系统对等亮度彩色光栅的空间调制传递函数（MTF），我们测量了等亮度红 - 绿和蓝 - 黄光栅在空间频率为0.125 - 4 c/deg时，作为视网膜照度函数的对比度敏感度。彩色光栅的对比度敏感度首先随亮度增加，遵循罗斯 - 德弗里斯定律，但随后增加饱和，对比度敏感度变得与光强无关，遵循韦伯定律。发现标志着定律之间转变点的临界视网膜照度（I(c)）在165 phot. td时与空间频率无关。根据我们的人类空间视觉检测模型，视网膜及后续神经视觉通路的MTF（P(c)）与√I(c)成正比。因此，P(c)与空间频率无关，这反映了在空间 - 颜色拮抗的视网膜神经节细胞和dLGN神经元中，对等亮度彩色刺激缺乏皮层前侧抑制。
