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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