Color appearance model: Difference between revisions

Revision as of 15:05, 12 August 2023

Revision as of 21:38, 21 September 2023

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RLAB tries to improve upon the significant limitations of [[#CIELAB|CIELAB]] with a focus on image reproduction. It performs well for this task and is simple to use, but not comprehensive enough for other applications.

Unlike CIELAB, RLAB uses a proper von Kries step. It also allows for tuning the degree of adaptation by allowing a customized ''D'' value. "Discounting-the-illuminant" can still be used by using a fixed value of 1.0.<ref>{{cite book | doi=10.1002/9781118653128.ch13 | chapter=The RLAB Model | title=Color Appearance Models | date=2013 | pages=243–255 | isbn=9781119967033 }}</ref>

===LLAB===

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| series = Proc. IS&T 6th Color Imaging Conference

| place = Scottsdale, AZ

| pages = 8–13.

| year = 1998

}}

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| year = 2016

}}

</ref> ICtCp can be transformed into an approximately uniform color space by scaling Ct by 0.5. This transformed color space is the basis of the Rec. 2124 wide gamut color difference metric ΔE_ITP.<ref>{{cite web |title=Recommendation ITU-R BT.2124-0 Objective metric for the assessment of the potential visibility of colour differences in television |url=https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.2124-0-201901-I!!PDF-E.pdf |date=January 2019}}</ref>

===[[CIECAM02]]===

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:A 2009 modification of CIELAB in the spirit of RLAB (with discounting-the-illuminant). Uses CIECAM02 chromatic adaptation matrix to fix the blue hue issue.<ref name=Levien>{{cite web |title=An interactive review of Oklab |url=https://raphlinus.github.io/color/2021/01/18/oklab-critique.html |first1=Raph |last1=Levien |language=en |date=18 January 2021}}</ref>

;{{vanchor|JzAzBz}}

:A 2017 UCS designed for HDR color. Has J (lightness) and two chromaticities.<ref>{{cite journal |last1=Safdar |first1=Muhammad |last2=Cui |first2=Guihua |last3=Kim |first3=Youn Jin |last4=Luo |first4=Ming Ronnier |title=Perceptually uniform color space for image signals including high dynamic range and wide gamut |journal=Optics Express |date=26 June 2017 |volume=25 |issue=13 |pages=1513115131–15151 |doi=10.1364/OE.25.015131|pmid=28788944 |bibcode=2017OExpr..2515131S |doi-access=free }}</ref>

;XYB

:A family of UCS used in [[Guetzli]] and [[JPEG XL]], with a main goal in compression. Better uniformity than CIELAB.<ref name=Levien/>