2011-05-03
Some facts in perspective
The "circular structure" may refer to various color "wheels" or "circles" under different systems of color classification, such as HSL/HSB. However, this has nothing at all to do with non-linearity of hue perception. That's determined by the physiology of cone cells. Response curves are different for each cone type and they do not evenly overlap each other. Likewise, the S cone has assymetrical sensitivity. The perceptual non-linearity of hue vs. wavelength is an "artifact" of biology, not a result of the "structure" of the hues. Likewise, variation exists among cone sensitivities among different individuals--and then there's the question of the "tetrachromat" (who has four distinct cones instead of the normal S/M/L triad), who might or might not exist.