Maloney L T
J Opt Soc Am A. 1986 Oct;3(10):1673-83. doi: 10.1364/josaa.3.001673.
Recent computational models of color vision demonstrate that it is possible to achieve exact color constancy over a limited range of lights and surfaces described by linear models. The success of these computational models hinges on whether any sizable range of surface spectral reflectances can be described by a linear model with about three parameters. In the first part of this paper, I analyze two large sets of empirical surface spectral reflectances and examine three conjectures concerning constraints on surface reflectance: that empirical surface reflectances fall within a linear model with a small number of parameters, that empirical surface reflectances fall within a linear model composed of band-limited functions with a small number of parameters, and that the shape of the spectral-sensitivity curves of human vision enhance the fit between empirical surface reflectances and a linear model. I conclude that the first and second conjectures hold for the two sets of spectral reflectances analyzed but that the number of parameters required to model the spectral reflectances is five to seven, not three. A reanalysis of the empirical data that takes human visual sensitivity into account gives more promising results. The linear models derived provide excellent fits to the data with as few as three or four parameters, confirming the third conjecture. The results suggest that constraints on possible surface-reflectance functions and the "filtering" properties of the shapes of the spectral-sensitivity curves of photoreceptors can both contribute to color constancy. In the last part of the paper I derive the relation between the number of photoreceptor classes present in vision and the "filtering" properties of each class. The results of this analysis reverse a conclusion reached by Barlow: the "filtering" properties of human photoreceptors are consistent with a trichromatic visual system that is color constant.
近期的颜色视觉计算模型表明，在由线性模型描述的有限范围的光照和表面条件下，实现精确的颜色恒常性是可能的。这些计算模型的成功取决于是否能用一个约有三个参数的线性模型来描述任何相当大范围内的表面光谱反射率。在本文的第一部分，我分析了两组大量的经验表面光谱反射率，并研究了关于表面反射率约束的三个猜想：经验表面反射率落在一个具有少量参数的线性模型范围内，经验表面反射率落在一个由具有少量参数的带限函数组成的线性模型范围内，以及人类视觉的光谱敏感度曲线形状增强了经验表面反射率与线性模型之间的拟合度。我得出结论，对于所分析的两组光谱反射率，第一个和第二个猜想成立，但对光谱反射率进行建模所需的参数数量是五到七个，而非三个。考虑到人类视觉敏感度对经验数据进行重新分析，得到了更有希望的结果。所推导的线性模型用少至三或四个参数就能很好地拟合数据，证实了第三个猜想。结果表明，对可能的表面反射率函数的约束以及光感受器光谱敏感度曲线形状的“滤波”特性都有助于颜色恒常性。在本文的最后一部分，我推导了视觉中存在的光感受器类别数量与每类光感受器的“滤波”特性之间的关系。这一分析结果推翻了巴洛得出的一个结论：人类光感受器的“滤波”特性与具有颜色恒常性的三色视觉系统是一致的。
