Frome F S, Buck S L, Boynton R M
J Opt Soc Am. 1981 Feb;71(2):145-50. doi: 10.1364/josa.71.000145.
The strength of the border between two regions was assessed by measuring the tendency of the border to disappear during a 5-min fixation period. We measured the total time the border was judged visible when subjects viewed two hemifields with different chromaticities (six wavelength pairs), five luminance contrasts, or with differences in both, at five levels of luminance. For a homochromatic field, border visibility increased linearly with the logarithm of the luminance contrast, regardless of the particular wavelength of the field. For fields with only chromatic differences, border visibility increased linearly with the logarithm of the tritanopic-purity difference (the relative activity of only the long- and middle-wavelength-sensitive cones). For all borders, visibility increased with an increase in luminance level. Thus borders formed by the combination of chromatic differences and luminance contrasts are more visible than borders that have the same chromatic difference or the same luminance contrast alone. For any chromatic difference, calculations of a luminance contrast that would yield the same border visibility were made. These equivalent luminance-contrast functions for border visibility provide a metric for chromatic differences across a range of luminances that allows chromatic and luminance-contrast sensitivities to be compared in a nonarbitrary way. Relative to chromatic differences, luminance contrast is less effective in maintaining border visibility at lower luminance levels. When the borders combine both chromatic differences and luminance contrasts, a root-mean-square model can be used to account for the data. This is consistent with the idea that chromatic and luminance systems make independent contributions to the visibility of borders.
通过测量在5分钟固定期内边界消失的趋势来评估两个区域之间边界的强度。当受试者观看具有不同色度（六对波长）、五种亮度对比度或两者都不同的两个半视野时，我们测量了边界被判断为可见的总时间，亮度水平分为五个等级。对于单色场，无论场的特定波长如何，边界可见性随亮度对比度的对数线性增加。对于仅有色度差异的场，边界可见性随三原色纯度差异（仅对长波长和中波长敏感的视锥细胞的相对活性）的对数线性增加。对于所有边界，可见性随亮度水平的增加而增加。因此，由色度差异和亮度对比度组合形成的边界比仅具有相同色度差异或相同亮度对比度的边界更明显。对于任何色度差异，计算出产生相同边界可见性的亮度对比度。这些边界可见性的等效亮度对比度函数提供了一种跨亮度范围的色度差异度量，使得色度和亮度对比度敏感度能够以非任意的方式进行比较。相对于色度差异，亮度对比度在较低亮度水平下维持边界可见性方面效果较差。当边界同时包含色度差异和亮度对比度时，可以使用均方根模型来解释数据。这与色度和亮度系统对边界可见性做出独立贡献的观点一致。
