GB/T 20147.4-2023 Active

This document specifies a method for calculating the luminance, chromaticity, and hue-related quantities of the CIE 1976 L*a*b* color space coordinates. It includes two methods for calculating the Euclidean geometric distance to represent color perception differences in the color space. This document is applicable to the CIE 1931 standard color system or the CIE 1964 standard color system, which use color-matching functions to calculate tristimulus values. This document can be used to describe the color characteristics of reflective or transmissive objects, in which case a more uniform three-dimensional color space than the tristimulus color space is required. This document is suitable for self-luminous displays, such as cathode ray tubes, if they are used to simulate the color stimuli of reflective or transmissive objects and the color stimuli have been properly normalized. This document is not applicable to areas primarily illuminated by the light source itself or to color stimuli that specularly reflect the illuminated area. The method for calculating the inverse transformation is provided in Appendix A.