Atdn: Toward a uniform color space

Abstract

AbstractTo derive a uniform chromaticity space for small color differences, we applied compressive intensity‐response functions of the form ρ = In/(σ + In) to each of the four color signals from the T (red vs. green) and D (blue vs. yellow) mechanisms of the ATD vector model for color vision. The values of σ and n for each response were optimized by computer iteration to provide reasonably uniform color spaces (ATDN) for describing the color‐discrimination data of MacAdam [J. Opt. Soc. Am. 32, 246‐274 (1942)] and Pointer [J. Opt. Soc. Am. 64, 750–759 (1974)]. To determine how well ATDN accounts for large color differences, we transformed the coordinates of the Munsell renotation system to ATDN space. Origin‐bound radial lines and origin‐centered circles in ATDN are about equivalent to those of CIELAB in approximating iso‐hue and iso‐sat‐uration contours of the Munsell system. A computer program written in BASIC that can be used to transform 1931 CIE X, Y, Z values to points in ATDN space is included as an appendix.