Christine Fernandez-Maloigne Editor Advanced Color Image Processing and Analysis 123 Editor ChristineFernandez-Maloigne Xlim-SICLaboratory UniversityofPoitiers 11BdMarieetPierreCurie Futuroscope France ISBN978-1-4419-6189-1 ISBN978-1-4419-6190-7(eBook) DOI10.1007/978-1-4419-6190-7 SpringerNewYorkHeidelbergDordrechtLondon LibraryofCongressControlNumber:2012939723 ©SpringerScience+BusinessMediaNewYork2013 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof thematerialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation, broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodology nowknownorhereafterdeveloped.Exemptedfromthislegalreservationarebriefexcerptsinconnection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. 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Printedonacid-freepaper SpringerispartofSpringerScience+BusinessMedia(www.springer.com) Preface Colorislifeandlifeiscolor! We liveourlifeincolorsandthenaturethatsurroundsusoffersthemall,inall theirnuances,includingthecolorsoftherainbow.Colorsinspireustoexpressour feelings.Wecanbe“redintheface”or“purplewithrage.”Wecanfeel“bluewith cold”inwinteror“greenwithenvy,”lookingatourneighbors’newcar.Or,arewe perhapstheblacksheepofourfamily?.... Color has accompanied us through the mists of time. The history of colors is indissociable,on the culturalas well as the economiclevel, fromthe discoveryof newpigmentsandnewdyes.Fromfourorfiveatthedawnofhumanity,thenumber ofdyeshasincreasedtoafewthousandstoday. AristotleascribedcolorandlighttoAntiquity.Atthetime,therewasanotherno- tionoftheconstitutionofcolors:perhapsinfluencedbytheimportanceofluminosity in the Mediterraneancountries, clearness and darknesswere dominatingconcepts compared to hues. Elsewhere, colors were only classified by their luminosity as whiteandblack.Hueswerelargelysecondaryandtheirrolelittleexploited.Itshould besaidthatitwasratherdifficultatthattimetoobtaindyesofferingsaturatedcolors. DuringtheMiddleAges,theprevalenceoftheperceptionofluminositycontinuedto influencethecomprehensionofcolor,andthisgenerallybecamemorecomplicated with the theological connotations and with the dual nature of light declining in Lumen,thesourceoflightofdivineorigin(forexample,solarlight)andLux,which acquiresa more sensory and perceptualaspect like the light of a very close wood fire,whichonecanhandle.Thisdualityisincludedinthemodernphotometricunits wherelumenistheunitthatdescribestheflowofthesourceoflightandLuxisthe unitofilluminationreceivedbyamaterialsurface.Thisdesignbasedonclearness, the notion taken up by the painters of the Renaissance as well under the term of value, continues to play a major role, in particular for graphic designers who are veryattachedtotheconceptofthecontrastofluminosityfortheharmonyofcolors. Inthisphilosophy,thereareonlytwoprimarycolors,whiteandblack,andtheother colorscanonlybequiteprecisemixturesofwhiteandblack.Wecannowmeasure thedistancethatseparatesourperceptionfromthatoftheoldentimes. v vi Preface Each color carries its own signature, its own vibration... its own universal language built over millennia! The Egyptians of Antiquity gave to the principal colors a symbolic value system resulting from the perception they had of natural phenomena in correlation with these colors: the yellow of the sun, the green of the vegetation, the black of the fertile ground, the blue of the sky, and the red of the desert. For religious paintings, the priests generally authorized only a limited numberofcolors:white,black,thethreebasiccolors(red,yellowandblue),ortheir combinations(green,brown,pinkandgray).Eversince,thelanguageofcolorhas madeitsway throughtime, andtodaytherapeutictechniquesuse colorsto convey thisuniversallanguagetotheunconscious,toopendoorstofacilitatethecure. Inthescientificworld,althoughthefundamentallawsofphysicswerediscovered inthe1930s,colorimetricshadtoawaittheriseofdataprocessingtobeabletouse themanymatrixalgebraapplicationsthatitimplies. Inthenumericalworld,colorisofvitalimportance,asitisnecessarytocodeand tomodel,whilerespectingthebasicphenomenaoftheperceptionofitsappearance, as we recall in Chaps. 1 and 2. Then color is measured numerically (Chap. 3), moves from one peripheral to another (Chap. 4), is handled (Chaps. 5–7), to extract automatically discriminating information from the images and the videos (Chaps.8–11) to allow an automatic analysis. It is also necessary to specifically protect this information, as we show in Chap. 12, to evaluate its quality, with the metrics and standardized protocols described in Chap. 13. It is with the two applicationsinwhichcoloriscentral,thefieldofartandthefieldofmedicine,that weconcludethiswork(Chaps.14and15),whichhasbroughttogetherauthorsfrom allthecontinents. Whetherlookedatasasymbolofjoyorofsorrow,singleorcombined,coloris indeedasymbolofunion!Thankstoit,Imetmanyimpassionedresearchersfrom aroundtheworldwhobecamemyfriends,whoarelikethemembersofabigfamily, richincolorsofskin,hair,eyes,landscapes,andemotions.Eachchapterofthiswill delivertoyouapartoftheenigmaofdigitalcolorimagingand,withinfiligree,the storiesofalltheserainbowmeetings.Goodreading! Contents 1 FundamentalsofColor..................................................... 1 M.JamesShyuandJussiParkkinen 2 CIECAM02andItsRecentDevelopments............................... 19 MingRonnierLuoandChangjunLi 3 ColourDifferenceEvaluation............................................. 59 ManuelMelgosa,AlainTre´meau,andGuihuaCui 4 Cross-MediaColorReproductionandDisplayCharacterization..... 81 Jean-BaptisteThomas,JonY.Hardeberg,andAlainTre´meau 5 DihedralColorFiltering................................................... 119 ReinerLenz,VasileiosZografos,andMartinSolli 6 ColorRepresentationandProcesseswithCliffordAlgebra ........... 147 PhilippeCarre´ andMichelBerthier 7 ImageSuper-Resolution,aState-of-the-ArtReview andEvaluation.............................................................. 181 AldoMaaloufandMohamed-ChakerLarabi 8 ColorImageSegmentation ................................................ 219 MihaiIvanovici,Noe¨lRichard,andDietrichPaulus 9 Parametric Stochastic Modeling for Color Image SegmentationandTextureCharacterization............................ 279 Imtnan-Ul-HaqueQazi,OlivierAlata,andZoltanKato 10 ColorInvariantsforObjectRecognition................................. 327 DamienMuseletandBrianFunt 11 MotionEstimationinColourImageSequences......................... 377 JennyBenois-Pineau,BrianC.Lovell,andRobertJ.Andrews vii viii Contents 12 ProtectionofColourImagesbySelectiveEncryption.................. 397 W.Puech,A.G.Bors,andJ.M.Rodrigues 13 QualityAssessmentofStillImages ....................................... 423 Mohamed-ChakerLarabi,ChristopheCharrier, andAbdelhakimSaadane 14 ImageSpectrometers,ColorHighFidelity,andFine-Art Paintings..................................................................... 449 AlejandroRibe´s 15 ApplicationofSpectralImagingtoElectronicEndoscopes............ 485 YoichiMiyake Index............................................................................... 499 Chapter 1 Fundamentals of Color M.JamesShyuandJussiParkkinen Thecoloristhegloryofthelight JeanGuitton Abstract Color is an importantfeaturein visualinformationreachingthe human eyeoranartificialvisualsystem.Thecolorinformationisbasedontheelectromag- netic(EM)radiationreflected,transmitted,orirradiatedbyanobjecttobeobserved. Distributionofthisradiationintensityis representedasa wavelengthspectrum.In the standard approach, color is seen as human sensation to this spectrum on the wavelengthrange380–780nm.Amoregeneralapproachistomanagecolorascolor informationcarriedbytheEMradiation.Thismodernapproachisnotrestrictedto thelimitationsofhumanvision.Thecolorcanbemanaged,notonlyinatraditional ∗ ∗ ∗ three-dimensionalspacelike RGBorL a b butalsoinann-dimensionalspectral space.Inthischapter,wedescribethebasisforbothapproachesanddiscusssome fundamentalquestionsincolorscience. Keywords Color fundamentals • Color theory • History of color theory • Col- orimetry • Advancedcolorimetry • Electromagneticradiation • Reflectancespec- trum • Metamerism • Standard observer • Color representation • Color space • Spectral color space • n-dimensional spectral space • Color signal • Human vision • Colordetectionsystem M.J.Shyu((cid:2)) DepartmentofInformationCommunications,ChineseCultureUniversity,Taipei,Taiwan e-mail:[email protected] J.Parkkinen SchoolofComputing,UniversityofEasternFinland,Joensuu,Finland SchoolofEngineering,MonashUniversitySunwayCampus,Selangor,Malaysia e-mail:[email protected] C.Fernandez-Maloigne(ed.),AdvancedColorImageProcessingandAnalysis, 1 DOI10.1007/978-1-4419-6190-7 1, ©SpringerScience+BusinessMediaNewYork2013 2 M.J.ShyuandJ.Parkkinen 1.1 EverythingStarts with Light The ability of human beings to perceive color is fantastic. Not only does it make it possible for us to see the world in a more vibrant way, but it also creates the wonder that we can express our emotionsby using variouscolors. In Fig.1.1, the colorsonthewoodenwindowarepaintedwiththemeaningofbringingprosperity. In a way, we see the wonderful world through the colors as a window. There are endlesswaystouse,tointerpret,andeventoprocesscolorwiththeversatilitythat isinthenatureofcolor.However,tobetterhandlethevocabularyofcolor,weneed to understand its attributes first. How to process as well as analyze color images for specific purposes under various conditionsis another importantsubject which furtherextendsthewonderofcolor. In the communication between humans, color is a fundamental property of objects.Welearndifferentcolorsinourearlychildhoodandthisseemstobeobvious forus.However,whenwestarttoanalyzecolormoreaccuratelyand,forexample, wanttomeasurecoloraccurately,itisnotsoobviousanymore.Foraccuratecolor measurement, understanding, and management, we need to answer the question: Whatiscolor? Fig.1.1 Acolorfulwindow withthethemeofbringing prosperity(Photographedby M.JamesShyuinPingtong, Taiwan) 1 FundamentalsofColor 3 In a common use of the term and as an attribute of an object, color is treated in many ways in human communication. Color has importance in many different disciplinesandthereareanumberofviewstothecolor:inbiology,colorvisionand colorization of plants and animals; in psychology, color vision; in medicine, eye diseasesandhumanvision;inart,colorasanemotionalexperience;inphysics,the signal carrying the color information and light matter interaction; in chemistry, themolecularstructureandcausesofcolor;intechnology,differentcolormeasuring anddisplaysystems;incultural,studiescolornaming;andinphilosophy,coloras anabstractentityrelatedtoobjectsthroughlanguage[2,9,28]. Itissaidthatthereisnocolorinthelight—toquoteSirIsaacNewton,“Forthe Raystospeakproperlyarenotcoloured.Inthemthereisnothingelsethanacertain Power and Disposition to stir up a Sensation of this or that Colour” [21,26]. It is theperceptionofhumanvisionthatgeneratesthefeelingofcolor.Itistheperceived color feeling of the human vision defining how we receive the physical property of light. Nevertheless,if color is only defined by humanvision, it leaves all other animals“colorblind.”However,itisknownthatmanyanimalsseecolorsandhave anevenrichercolorworldthanhumanbeing[13,19]. The new technologicaldevelopmentin illumination and in camera and display technologyrequiresnewwayofmanagingcolors.RGBorotherthree-dimensional colorrepresentationsarenotenoughanymore.Thelight-emittingdiodes(LED)are comingintoilluminationanddisplaysrapidly.There,thecolorradiationspectrumis sopeakythatmanagingitrequiresamoreaccuratecolorrepresentationthanRGB. Thereexistalsodigitalcamerasanddisplays,wherecolorsarerepresentedbyfour orsixcolors.Alsothistechnologyrequiresnewwaystoexpressandcomputecolor values. Therefore,ifwewanttounderstandcolorthoroughlyandbeabletomanagecolor in all purposes, where it is used today, we cannot restrict ourselves to the human vision.We have to look colorthroughthe signal, whichcauses colorsensation by humans.Thissignalwecallcolorsignalorcolorspectrum. 1.2 Development of ColorTheory Incolorvocabulary,blackandwhite arethe firstwordstobe usedas colornames [2].Afterthemwhenthelanguagedevelops,comeredandyellow.Thevocabulary is naturally related to the understandingof nature. Thereforein ancient times, the color names were related to the four basic elements of the world, water, air, fire, andearth[9].Inancienttimes,thecolortheorywasdevelopedbyphilosopherslike PlatoandAristotle.Forthelaterdevelopmentofcolortheory,itisnotablethatwhite wasseenasabasiccolor.Alsothecolormixturesweretakenintotheories,buteach basiccolorwasconsideredtobeasingleandseparateentity[14]. AlsofromthepointofviewoftherevolutionofcolortheorybyNewton[20],itis interestingtonotethatAristotlehadasevenbasiccolorscale,wherecolorscrimson, 4 M.J.ShyuandJ.Parkkinen a 1 0.9 0.8 B 0.7 G 0.6 R 0.5 Y 0.4 M 0.3 C 0.2 0.1 0 380 430 480 530 580 630 680 730 b > m o ok.c o b e w o w w. Fig.1.2 (a) A set ofcolorspectra (x-axis: wavelength from 380 to730nm,y-axis: reflectance w w factor)and(b)thecorrespondingcolors < ok o B e w! violet,leek-green,deepblue,andgrayoryellowformedthecolorscalefromblack o W m towhite[9].Aristotlealsoexplainsthecolorsensationso,thatcolorsetstheairin o d fr movementandthatmovementextendsfromobjecttotheeye[24]. a nlo From these theories, one can see that already in ancient times, there exists the w Do idea of some colors to be mixtures of primary colors and seven primary colors. Also, it is easy to understand the upcoming problems of Newton’s description of colors,when the view was that each primarycoloris a single entity and the color sensationwasseenasakindofmechanicalcontactbetweenlightandtheeye.The ancientwayofthinkingwasstronguntiltheSeventeenthcentury. InthemiddleoftheSeventeenthcentury,thecollectedinformationwasenough to break the theory of ancient Greek about light and color. There were a number of experiments by prism and color in the early Seventeenth century. The credit for the discovery of the nature of light as a spectrum of wavelengths is given to Isaac Newton [20]. The idea that colors are formed as a combination of different component rays, which are immaterial by nature, was revolutionary at Newton’s time. It broke the strong influence of ancient Greek thinking. This revolutionary ideawasnoteasilyaccepted.AnotablepersonwasJohannWolfgangvonGoethe, whowasstillintheNineteenthcenturyopposingNewton’stheorystrongly[10]. Newton also presented colors in a color circle. In his idea, there were seven basiccolors:violet,indigo,blue,green,yellow,orange,andred[14].Inthespectral approachtocolorasshowninFig.1.2,thewavelengthscaleislinearandcontinuing