The Vos and Walraven cone fundamentals were obtained from the following transformations
where , and are the Judd, Vos modified CIE, XYZ 2-deg color matching functions.
See Vos and Walraven (1971), Walraven (1974) and Vos (1978)
Note that L(λ)+M(λ)+S(λ) = V(λ).
Vos, J. J. & Walraven, P. L. (1971). On the derivation of the foveal receptor primaries. Vision Research, 11, 799-818.
Vos, J. J. (1978). Colorimetric and photometric properties of a 2-deg fundamental observer. Color Research and Application, 3, 125-128.
Walraven, P. L. (1974). A closer look at the tritanopic confusion point. Vision Research, 14, 1339-1343.