数字图像处理-冈萨雷斯-课件(英文)Chapter02Eng 数字图像基础.ppt

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1、DigitalImageProcessingChapter2:DigitalImageFundamental6June2007WhatisDigitalImageProcessing?ProcessingofamultidimensionalpicturesbyadigitalcomputerWhyweneedDigitalImageProcessing?TorecordandstoreimagesToenhanceimagesusingmathematicsToanalysisimagesTosynthesizeimagesTocreatecomputervisi

2、onsystemsDigitalImageDigitalimage=amultidimensionalarrayofnumbers(suchasintensityimage)orvectors(suchascolorimage)Eachcomponentintheimagecalledpixelassociateswiththepixelvalue(asinglenumberinthecaseofintensityimagesoravectorinthecaseofcolorimages).VisualPerception:HumanEye(PicturefromM

3、icrosoftEncarta2000)CrossSectionoftheHumanEye(ImagesfromRafaelC.GonzalezandRichardE.Wood,DigitalImageProcessing,2ndEdition.Thelenscontains60-70%water,6%offat.Theirisdiaphragmcontrolsamountoflightthatenterstheeye.Lightreceptorsintheretina-About6-7millionsconesforbrightlightvisioncalledp

4、hotopic-Densityofconesisabout150,000elements/mm2.-Conesinvolveincolorvision.-Conesareconcentratedinfoveaabout1.5x1.5mm2.-About75-150millionsrodsfordimlightvisioncalledscotopic-Rodsaresensitivetolowleveloflightandarenotinvolvedcolorvision.4.Blindspotistheregionofemergenceoftheopticnerve

5、fromtheeye.VisualPerception:HumanEye(cont.)RangeofRelativeBrightnessSensationSimutaneousrangeissmallerthanTotaladaptationrange(ImagesfromRafaelC.GonzalezandRichardE.Wood,DigitalImageProcessing,2ndEdition.DistributionofRodsandConesintheRetina(ImagesfromRafaelC.GonzalezandRichardE.Wood,D

6、igitalImageProcessing,2ndEdition.ImageFormationintheHumanEye(PicturefromMicrosoftEncarta2000)(ImagesfromRafaelC.GonzalezandRichardE.Wood,DigitalImageProcessing,2ndEdition.PositionIntensityBrightnessAdaptationofHumanEye:MachBandEffectMachBandEffectIntensitiesofsurroundingpointseffectper

7、ceivedbrightnessateachpoint.Inthisimage,edgesbetweenbarsappearbrighterontherightsideanddarkerontheleftside.(ImagesfromRafaelC.GonzalezandRichardE.Wood,DigitalImageProcessing,2ndEdition.InareaA,brightnessperceivedisdarkerwhileinareaBisbrighter.ThisphenomenoniscalledMachBandEffect.Posi