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Viewing Conditions and Chromatic Adaptation
Visual Perception Spring 2008
Instructor: Prof. Aditi MajumderStudent: Hamed Pirsiavash
Agenda
Viewing fieldChromatic adaptationChromatic adaptation models
Linearnonlinear
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Viewing field
Self-luminous displaysCRT, LCD
Reflective mediaPainting
Viewing field
CIE illuminantD65, D50, A, F2, F8
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Viewing field
Modes of viewing
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Modes of viewing
Chromatic adaptation
Light adaptationTurning on the light in dark night
Dark adaptationEntering a dark movie theater
Chromatic adaptation
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Chromatic adaptationOriginal scene
Chromatic adaptationWithout chromatic adaptation (Tungsten illumination)
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Chromatic adaptationAfter chromatic adaptation
Chromatic adaptation
PhysiologyPupil Dilation/constrictionRod-cone transitionReceptor gain controlSubtractive mechanismsHigh-level adaptation
Spatial frequency adaptationMotion adaptation
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Chromatic adaptation models
Transformation from XYZ (tristimulus values) to LMS (cone responsitives)
Chromatic adaptation models
From XYZ to LMS
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Chromatic adaptation models
Von Kries model (1902)
Von Kries model
Von Kries model in matrix formIndependent channels
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Von Kries model
Transformation from one viewing condition to another
Von Kries model
Experimental results
Dark triangles: Von Kriesmodel
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Chromatic adaptation models
Retinex theory (1971)Use spatial distribution of scene colorsColor appearance is
Surface reflectionNot the distribution of reflected light
Normalize the output of each sensor with average over the scene.
Nayatani’s model (1980)
NonlinearClose to MacAdam’smodel (1961) Noise term is added
Helps in low inllumination
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Guth’s model (1991)
Sigma is a noise term
Guth’s model (1991)
Comparison with Von Kriesmodel
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Fairchild’s model (1991)
Fairchild’s model (1991)
Subscript n:Adapting stimulus
Subscript E:Equal energy illumination
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Fairchild’s model (1991)
Inter channel correlationLater he removed this matrix
Fairchild’s model (1991)
Transformation from one viewing condition to another
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Fairchild’s model (1991)
Cat02 Model (2002)
A linear model used in CIE 2004
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Thanks for your attention