基于不同颜色方向和空间频率的彩色对比灵敏度特性研究

Investigation of Chromatic Contrast Sensitivity Based on Different Color Directions and Spatial Frequencies

为了研究不同空间频率和颜色方向的彩色对比灵敏度特性,在0.5～11.7 cycle/(°)的空间频率范围内分别在6°和10°视场下以灰色或红色为颜色中心,在CIELAB颜色空间的等亮度面上选取6个颜色方向,采用交叉阶梯法通过心理物理视觉实验测得以色差阈值倒数定义的彩色对比灵敏度。基于实验数据比较了不同颜色方向上低通形式的彩色对比灵敏度函数(CSF)曲线,并拟合得到不同空间频率下的彩色对比度阈值椭圆。随空间频率增大,阈值椭圆的面积变大,长短半轴比变化,同时发生旋转,导致彩色对比灵敏度随空间频率和颜色方向而改变,即色貌随空间频率的变化;视场增大使椭圆方位角的峰值以及长短半轴比的波动区间向低频方向移动,且红色中心的变化趋势与相应视场的灰色中心相似,只是总体数值偏低。

Based on the interleaved staircase method,the psychophysical visual experiment is carried out to investigate the spatial and color directional characteristics of chromatic contrast sensitivity.For the spatial frequencies from 0.5 to 11.7 cycle /（°） under the viewing field of 6° and 10°,the chromatic contrast sensitivity which is defined as the reciprocal of the color-difference threshold is measured in 6 color directions in the iso-luminance plane of CIELAB color space at the two color centers of gray and red.The low-pass chromatic contrast sensitivity functions（CSF） of different color directions are compared,and the chromatic contrast threshold ellipses of different frequencies are fitted.With the increase of spatial frequency,the ellipse rotate with larger sizes and change ratio of semi-axis,which results in the change of chromatic contrast sensitivity with spatial frequencies and color directions,and implies the change of color appearance with the spatial frequencies.With the increase of viewing field,the ellipses′ peak azimuths and the fluctuation bands of semi-axis ratio shift to the lower frequencies,the tendency of which for red center is similar,but with lower values,to that of gray center under the same viewing field.