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ImprovingColorMatching UsingiccMAX

ChrisBai,ChiefColorScientist,BenQ Corporation

Overview

• WhatHappened?

• SomeMoreResearch…

• ThePlan

• Result

• Conclusion

• FutureWork

WhatHappened?

• WhenBenQ 1st LEDbacklightcolormanagementmonitorwasannounced in2013.

• Veryexcitingnews!

• ExperiencedusersfoundoutLEDbacklightmonitordidnotperformedwellinsoftproofingscenario.

ExperiencedObserver

???

Symptoms

• Variationsinblue,greenandpaleyellowtones,forexample.

• Differenceinperceivedsaturation.

LEDBacklightMonitor(Simulated)

ViewingBooth(Simulated)

Slighthueshiftinblue

Slighthueshiftingreen

Slighthueshiftinpaleyellow

Overallsaturationisdifferent

WhatwasWrong?

• ΔE00* ismoreorlessthesame…

TestedwithIT8.7/41617Patches:• LEDMonitor:

• Avg.ΔE00* =1.25• Max.ΔE00* =4.35

• CCFLMonitor:• Avg.ΔE00* =1.20• Max.ΔE00* =4.25

Notmuchdifferencefromthevaluesalone.

SomeMoreResearch…

• CIEReport* suggested:“Apotentialpracticalsolutionistoimplementanobserver-dependentcolorimagingworkflowatthedevicelevel.… Conceptuallythisissimilartothedevice-dependentcolorimaging,awell-establishedcolormanagementconcept.“

• Butnospectralcolormanagementworkflowwasestablishedatthattime.

• OnlyStandardObservercouldbeapplied.

*CIEFinalReportforR1-54:VariabilityInColor-MatchingFunctions

ObserverVariations

*Y.Asano,MSCL,RIT,USAhttp://www.cis.rit.edu/~yxa8513/Research.html

ThePlan

• TofindapotentialsolutionforLEDbacklightmonitors(andothernarrowbandwidthdisplaydevices).• Narrowbandwidthdisplaydevicesarebecomingextremelypopularoverthelast2years.

• TovalidateiccMAX frameworkinrealworldapplication.

ExperimentFlow

ObtainIndividualCMF

IncorporateCMFintoDisplayPipeline

PairComparisonExperiment

HopeThisHelps…

SelectObservers12ppl,6Male&6Female,

25~40yearsold

ObtainDataPoints14patches,10° field,

7selections

Connectthe“Dots”Usinginterpretationmethodwith

CIECategorizedObserver

MeasureDisplaySPD’sCCFLv.s.LED

IncorporatingiccMAXDisplaySPD’s&CMF

ValidationTestOriginalPatchSet+TestSet

PracticalTest8 TestImages

MimicCCFLMonitor ImprovingColorMatching

ColorPatchSelection

14Patches

*Y.Asano,MSCL,RIT,USAhttp://www.cis.rit.edu/~yxa8513/Research.html

Categorization

• It’sverydifficultandtimeconsumingtoobtainindividual’sCMF.• Apparatusisalsoanotherdifficulty…

• UsedcategorizedmethodtodetermineCMF:• AssuggestedinCIEFinalReport*

• 14colorpatcheswereusedtodeterminefixeddatapoints

• Interpretationwasusedtoobtaintheintermediatedatapoints

*CIEFinalReportforR1-54:VariabilityInColor-MatchingFunctions

Interface

ExperimentSetup

iccMAX Workflow

DestinationProfileB2D0Tag

SourceProfileD2B0Tag

CalibrationTarget:D65,160cd/m2,Gamma2.2

SpectralProfileConnectionSpace

ObserverCMF

TestImages

TestImage1 TestImage2 TestImage3

TestImage5

TestImage4

TestImage6 TestImage7 TestImage8

Result

TestImage1

BEFO

RE

No.ofAcceptable 7 9 3 4

No.ofUnacceptable 5 3 9 8

RateofAcceptable 58.3% 75.0% 25.0% 33.3%

AFTER

No.ofAcceptable 9 10 8 6

No.ofUnacceptable 3 2 4 6

RateofAcceptable 75.0% 83.3% 66.7% 50.0%

Improvement +16.7% +8.3% +41.7% +16.7%

TestImage2 TestImage3TestImage4

ResultBE

FORE

No.ofAcceptable 4 8 6 5

No.ofUnacceptable 8 4 6 7

RateofAcceptable 33.3% 66.7% 50.0% 41.7%

AFTER

No.ofAcceptable 3 10 9 6

No.ofUnacceptable 9 2 3 6

RateofAcceptable 25.0% 83.3% 75.0% 50.0%

Improvement -8.3% +16.6% +25.0% +8.3%

TestImage5 TestImage6 TestImage7 TestImage8

WhatDoImagesLookLikeforOneObserver?

Before

Original

After

TestIm

age1

Before

Original

After

TestIm

age2

Before

Original

After

TestIm

age3

Before

Original

After

TestIm

age4

WhatDoImagesLookLikeforOneObserver?

Before

Original

After

TestIm

age5

Before

Original

After

TestIm

age6

Before

Original

After

TestIm

age7

Before

Original

After

TestIm

age8

Conclusion

• ImprovementwasshownafterutilizingiccMAX workflow.• Blueandgreentones

• Saturatedcolors

• Someareastillneedsfurtherinvestigation:• Paleandlowbrightnesscolors

• Skintone

• Redtones

• Overall,withproperadjustment,iccMAX isthekeytosolveobservermetamerism onnarrowbandemissiondevices.

FutureWork

1.Moreobserverswithdifferentage,ethicgroups,experiencelevel…

2. Incorporatemorewidegamutdisplayswithdifferentspectralcharacteristics:(Inprogress…)• QuantumDotTechnology

• LaserDiode+LEDTechnology(RedLaserDiode+CyanLED)

• OLED

3. ImprovementonCMFestimation:• ValidatecurrentCMFestimation.

• Abetterfittingalgorithmfor“connectingthedots”.

• Constructarobustandsimplifiedmethodtoestimateindividual’sCMF.

FutureWork

4. Matchingtohardcopiesunderdifferentlightsourcetypes• Fluorescentlight

• LEDlight

ThankYouforYourAttention