ProLab: A Perceptually Uniform Projective Color Coordinate System
Иван Коноваленко, Анна Смагина, Dmitry Nikolaev, Nikolaev Pp
Abstract
In this work, we propose proLab, a new color coordinate system derived as a 3D projective transformation of CIE XYZ. We show that proLab is far superior to the widely used CIELAB coordinate system (though inferior to the modern CAM16-UCS) in terms of perceptual uniformity, evaluated by the STRESS metric in reference to the CIEDE2000 color difference formula. At the same time, angular errors of chromaticity estimation that are standard for linear color spaces can also be used in proLab since projective transformations preserve the linearity of manifolds. Unlike in linear spaces, angular errors for different hues are normalized according to the human color discrimination thresholds within proLab.We also demonstrate that shot noise in proLab is more homoscedastic than in CAM16-UCS or other standard color spaces. This makes proLab a convenient coordinate system in which to perform linear color analysis.