In trichromats, color vision entails the projection of an infinite-dimensional space (the one containing all possible electromagnetic power spectra) onto the three-dimensional space that modulates the activity of the three types of cones. This drastic reduction in dimensionality gives rise to metamerism, that is, the perceptual chromatic equivalence between two different light spectra. The classes of equivalence of metamerism are revealed by color-matching experiments in which observers adjust the intensity of three monochromatic light beams of three preset wavelengths (the primaries) to produce a mixture that is perceptually equal to a given monochromatic target stimulus. Here we use the linear relation between the color matching functions and the absorption probabilities of each type of cone to find particularly useful triplets of primaries. As a second goal, we also derive an analytical description of the trial-to-trial variability and the correlations of color matching functions stemming from Poissonian noise in photon capture. We analyze how the statistical properties of the responses to color-matching experiments vary with the retinal composition and the wavelengths of peak absorption probability, and compare them with experimental data on subject-to-subject variability obtained previously.

在三色视觉中，色觉需要将无限维空间（包含所有可能的电磁功率谱的空间）投影到调节三种视锥细胞活动的三维空间。这种维度的急剧减少导致了同色异谱，即两个不同光谱之间的感知色等价。通过颜色匹配实验揭示了同色异谱的等价类，其中观察者调整三个预设波长（原色）的三个单色光束的强度) 以产生在感知上等于给定单色目标刺激的混合物。在这里，我们使用颜色匹配函数和每种锥体的吸收概率之间的线性关系来找到特别有用的三元组。作为第二个目标，我们还得出了对试验间变异性的分析描述以及源自光子捕获中泊松噪声的颜色匹配函数的相关性。我们分析了颜色匹配实验响应的统计特性如何随视网膜成分和峰值吸收概率的波长而变化，并将它们与先前获得的受试者间变异性的实验数据进行比较。