Quick Gamut mapping for simplified color correction

Abstract

This paper presents an alternative method to convert color spaces more quickly than using the traditional gamut mapping. The conversion is carried out in a two-dimensional space, the xy chromaticity diagram, through an affine transformation, which changes the colors chromaticity, varying the saturation and hue, without acting on the luminance. The affine transformation applies to the colors of the original image the values obtained by solving two linear systems of three equations using the coordinates of the input and output color spaces. Then, these values are applied to each xy coordinate of the image color obtained from its RGB values.

Purpose of this alternative method is not the colorimetric accuracy, but a quick transformation to support the color correction of images and/ or videos. In image and video editing, the steps of color correction and color grading are often performed by the expert’s eye using various image editing tools and software. This approach overshadows the colorimetric aspect, focusing just on the aesthetic enhancement. The proposed alternative gamut mapping method, named Quick Gamut, will be presented through application examples.