Transformations from cone responses to opponent color spaces.

We have described a number of transformations by mapping the cone signal vector C, formed by LMS, to opponent space O, formed by achromatic signal OA, red‐green signal Org, and yellow‐blue signal Oyb. Two new transformations, Γop1 and Γop2, are proposed, based on the CIE 2006 spectral luminous efficiency function, VFλ, and Hurvich's opponent spectral red‐green and yellow‐blue responses, Hrgλ and Hybλ, without and with constraints, respectively. Γop1 is better than Γop2 in terms of best fit of Hrgλ and Hybλ, and both transformations improved previously proposed ones. Finally, we discuss the neutral conditions in cone space using each of the new and some of the extant transformations, as well as choosing scaling factors so that the neutral conditions in cone space are satisfied. [ABSTRACT FROM AUTHOR]