Euclidean color-difference formula for small-medium color differences in log-compressed OSA-UCS space

This work continues previous research by the same authors [J. Opt. Soc. Am. A 23, 2077 (2006)], where empirical small–medium color differences were represented by an ellipsoidal equation EGP in the Uniform Color System of the Optical Society of America. Now logarithmic compressions on chroma and lightness are introduced to produce a new space with Euclidean color-difference formulas EE. The CIEDE2000, EGP, and EE formulas are found statistically equivalent in the prediction of many available empirical datasets. However, EE is the simplest formula providing relationships with visual processing. These analyses hold true for CIE 1964 Supplementary Standard Observer and D65 illuminant.