Color appearance model: Difference between revisions

Revision as of 02:17, 12 June 2017

Revision as of 20:51, 3 May 2018

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In 1976, the [[International Commission on Illumination|CIE]] set out to replace the many existing, incompatible color difference models by a new, universal model for color difference. They tried to achieve this goal by creating a ''perceptually uniform'' color space, i.e. a color space where identical spatial distance between two colors equals identical amount of perceived color difference. Though they succeeded only partially, they thereby created the [[Lab color space#CIELAB|CIELAB (“L*a*b*”)]] color space which had all the necessary features to become the first color appearance model. While CIELAB is a very rudimentary color appearance model, it is one of the most widely used because it has become one of the building blocks of [[color management]] with [[ICC profile]]s. Therefore, it is basically omnipresent in digital imaging.

One of the limitations of CIELAB is that it does not offer a full-fledged chromatic adaptation in that it performs the [[von Kries transform]] method directly in the XYZ color space (often referred to as “wrong von Kries transform”), instead of changing into the [[LMS color space]] beforefirst for more precise results. ICC profiles circumvent this shortcoming by using the [[LMS color space#CIECAM97s, LLAB|Bradford transformation matrix]] to the LMS color space (which had first appeared in the [[#LLAB|LLAB color appearance model]]) in conjunction with CIELAB.

===Nayatani et al. model===