空间域图像增强-外文翻译

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1、附录A3ImageEnhancementintheSpatialDomainTheprincipalobjectiveofenhancementistoprocessanimagesothattheresultismoresuitablethantheoriginalimageforaspecificapplication.Thewordspecificisimportant,becauseitestablishesattheoutsetthanthetechniquesdiscussedinthischapterareverymuchpr

2、oblemoriented.Thus,forexample,amethodthatisquiteusefulforenhancingX-rayimagesmaynotnecessarilybethebestapproachforenhancingpicturesofMarstransmittedbyaspaceprobe.Regardlessofthemethodused.However,imageenhancementisoneofthemostinterestingandvisuallyappealingareasofimageproc

3、essing.Imageenhancementapproachesfallintotwobroadcategories:spatialdomainmethodsandfrequencydomainmethods.Thetermspatialdomainreferstotheimageplaneitself,andapproachesinthiscategoryarebasedondirectmanipulationofpixelsinanimage.Fouriertransformofanimage.Spatialmethodsarecov

4、eredinthischapter,andfrequencydomainenhancementisdiscussedinChapter4.Enhancementtechniquesbasedonvariouscombinationsofmethodsfromthesetwocategoriesarenotunusual.Wenotealsothatmanyofthefundamentaltechniquesintroducedinthischapterinthecontextofenhancementareusedinsubsequentc

5、haptersforavarietyofotherimageprocessingapplications.Thereisnogeneraltheoryofimageenhancement.Whenanimageisprocessedforvisualinterpretation,thevieweristheultimatejudgeofhowwellaparticularmethodworks.Visualevaluationofimagequalityisahighlyishighlysubjectiveprocess,thusmakin

6、gthedefinitionofa“goodimage”anelusivestandardbywhichtocomparealgorithmperformance.Whentheproblemisoneofprocessingimagesformachineperception,theevaluationtaskissomewhateasier.Forexample,indealingwithacharacterrecognitionapplication,andleavingasideotherissuessuchascomputatio

7、nalrequirements,thebestimageprocessingmethodwouldbetheoneyieldingthebestmachinerecognitionresults.However,eveninsituationswhenaclear-cutcriterionofperformancecanbeimposedontheproblem,acertainamountoftrialanderrorusuallyisrequiredbeforeaparticularimageenhancementapproachiss

8、elected.3.1BackgroundAsindicatedpreviously,thetermspatialdomainreferstotheaggregateofpixe