CS681 Computational Colorimetry - KAISTvclab.kaist.ac.kr/cs681/01_CS681_color(1).pdf · •Learn...

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MinH.Kim(KAIST) CS681:ComputationalColorimetry

CS681ComputationalColorimetry

MinH.KimKAISTSchoolofComputing


INTRODUCTIONAboutCS681ComputationalColorimetry

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Courseinformation:CS681• Subject:ComputationalColorimetry• Date:TuesdayandThursday• Time:10:30AM—11:45PM• Place:Rm.3444,Bldg.E3-1


AboutInstructor• Dr.MinHyukKim(김민혁)

– ProfessoratKAISTSchoolofComputing– ResearcheratYaleUniversity– PhDinComputerScience(UCL2010)– AssociateeditorofACMTOG(TopCSJournal)&ACMTAP– ProgramcommitteeofACMSIGGRAPHAsia,Eurographics,etc.– MicrosoftNewFacultyAward&Naver YoungFacultyFellowship– BestPaperAwards(ACCV,VAST)

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AboutInstructor

• Office:Rm.3429,Bldg.E3-1• Officehours:TuesdayandThursday16:00—17:00(pleaseletmeknowinadvance)

• E-mail:[email protected]


AboutTeachingAssistant

• TeachingAssistant:Giljoo Nam,PhDstudentatVCLAB

• Office:Rm.3422,Bldg.E3-1• Email:[email protected]

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Courseinformation:CS681

• 3-creditcourse• Yourgradewillbecalculatedby:– Classparticipation:10%–Midterm/finalexams:50%– Assignments:30%– Classquizzes(atthebeginningoflectures):10%


CourseWebsite• http://vclab.kaist.ac.kr/cs681/

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Textbook• RoyS.Berns (2000)PrinciplesofColorTechnology,3rdEd.,JohnWiley&Sons,Inc.

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References

• TheReproductionofColour,6thEd.,R.W.G.Hunt(2004)

• MeasuringColour,4st Ed.,R.W.GHunt,M.R.Pointer(2011)

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References

• ColorAppearanceModels,2nd

Ed.,Fairchild(2005)

• Colorimetry,1st Ed.,Ohta andRobertson(2005)


References

• ColorImaging,1st Ed.,Reinhardetal.(2008)

• HighDynamicRangeImaging,2nd Ed.,Reinhard etal.(2010)

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References

• DigitalModelingofMaterialAppearance,1st Ed.,Dorseyetal.(2008)


Objectives:CS681• Learnfundamentalsabout…– Theoreticalbackgroundaboutcolor– Advanceddigitalcolorimaging(advancedtechniquesbyusingadigitalcameraandcomputerdisplay)

– Latestcomputationalapplicationsaboutcolor

• Homeworkaboutcolorimageprocessing

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TentativeSyllabus


INTRODUCTION

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IntroductiontoResearchAreas

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COLOR(1)

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Color• Wehavebeenusingr,g,b…• Why?• Whatisacolor?• Canwegetallcolorsthisway?• Howdoeswavelengthfitinhere,whatpartisphysics,whatpartisphysiology.

• CanIuser,g,bforsimulationofreflection?• Howshouldcolorsbestored.

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Differentmeaningsofcolor• Neuralresponseofconecells:retinalcolor• Thisisprocessedgivingus:perceivedcolorthatweactuallyexperienceandbasejudgmentsupon.– Notewedonothavedirectexperientialaccesstoretinalcolor

• Theperceivedcolorisoftenassociatedwiththeobject.Weareobserving,whichwemightcalltheobjectcolor.

• Weorganizecolorsandnamethemaswell.20

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Color• Humanvisualsystemtransformsradiationintosensation

Vis

ible

Lig

ht

700 n

m600 n

m500 n

m400 n

m

red

Ora

ng

eyello

wg

reen

blu

ein

dig

ovio

let

Perceptualresponse

Sensibleonly380~780nm

Physicalstimuli

Electromagneticradiation

Colorexistsonlyinourbrain!


Newton’sExperiment

Newton’sbirthplace(1642)atWoolsthorpe Manor,Lincolnshire

UsingaprismtoproduceaspectrumCambridgeTrinityCollege,1665

Firstscientificdiscoveryofcolor

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Newton’sApparatus

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Light is a mixture of differently refrangible rays- Isaac Newton, Opticks

Hole

LensPrismScreenHole

Narrow-bandcolor


Visible?Invisiblespectrum?

• Visiblelight:400-700nm• Barely one octave out of

40 is visible to the eye

• Invisiblelight:– X-ray:1nm– Microwave:1cm– Radar:10cm– UHF,VHF,FMradio:1-10m– AMradio:100-1000m

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Definitionofspectralregions

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MeasuringColor

• Solid-statearray-basedsystem• Dispersiveelement:eitherprismordiffractiongrating

• Theonethatwetriedlasttime

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Lightbeams• Visiblelightiselectromagneticradiationthatfallsroughlyinthewavelengthsof380<λ <770,measuredinnanometers.

• Apurebeamlλ hasone“unit”oflightofaspecificwavelength λ.

• Amixedbeaml(λ) hasdifferentamountsofvariouswavelengths.– Theseamountsaredeterminedbythefunction

– Thevalueisalwaysnon-negativesincethereisno“negativelight”.

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l(⋅) :R→ R+


ComputingReflectancefromRadiance

• Radiance:energyperunitareapersolidangle• Reflectance:energyatspecifiedangle,relativetoenergy

reflectedbyperfectdiffuser• Foraconstantly-illuminatedsurface,thereflectanceatagiven

angleisgivenby:

• Sincetheradianceofaperfectdiffuserisnotknown,itcanbefoundbymeasuringtheradiancereflectedonacalibrationtilewithknownreflectance(whitetile,so-calledSpectralon).

R(λ)sample =I(λ)sampleI(λ)reference

I(λ)reference =I(λ)calibrationR(λ)calibration

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Light

Spectralradiation

Spectralreflectance

Spectralreflection

Observer


Light

Spectralradiation

Spectralreflectance

Spectralreflection

Observer

ObserverResponse

( )P l

( )r l

( ) ( )P l r l

( )V l

( ) ( ) ( )V Pl l r l( ) : Visual response( ) : Object spectrum( ) : Illumination spectrum

V

P

lr ll

CS681 Computational Colorimetry - KAISTvclab.kaist.ac.kr/cs681/01_CS681_color(1).pdf · •Learn...

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Transcript of CS681 Computational Colorimetry - KAISTvclab.kaist.ac.kr/cs681/01_CS681_color(1).pdf · •Learn...