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. A23, 2077 (2006)], where empirical small-medium color differences were represented by an ellipsoidal equation DeltaEGP 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 DeltaEE. The CIEDE2000, DeltaEGP, and DeltaEE formulas are found statistically equivalent in the prediction of many available empirical datasets. However, DeltaEE is the simplest formula providing relationships with visual processing. These analyses hold true for CIE 1964 Supplementary Standard Observer and D65 illuminant.