A comprehensive test of colour-difference formulae and uniform colour spaces using available visual datasets

Abstract

The paper describes a comprehensive test to evaluate the performance of current colour-difference models using available experimental datasets. In total, 28 individual datasets were accumulated to test 17 colour-difference formulae, 13 of them based on Uniform Colour Spaces (UCSs) in terms of the Standardized Residual Sum of Squares (STRESS) measure. The 28 datasets were divided into three groups: Large Colour-Difference data (LCD), Small Colour-Difference data for surface colours (SCDs), and Small Colour Difference data for display colours (SCDd). For each colour model, four versions were tested: the original model, and that including k_L-, Gamma- and k_L/Gamma, which are the lightness parametric factor, the colour-difference exponent factor, and the combination of both, respectively, optimized to fit particular dataset(s). The statistical F-test was applied to test the difference between each pair of models. Furthermore, parametric effects between the large/small colour-difference magnitudes, and between surface/display colours were investigated. The results showed that CAM16-UCS significantly outperformed the other models for all groups. It accurately predicted all types of data and should be proposed for colour-difference evaluation across all industries.