英文文献1 原稿

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1、Contents1.Theory-2-2.Implementation-4-3.Example-4-4.Variationsandextensions-6-4.1Usingthegradientdirectiontoreducethenumberofvotes-6-4.2Kernel-basedHoughtransform-7-4.3Houghtransformofcurves,andGeneralisedHoughtransform-7-4.4Detectionof3Dobjects(Planesandcylinders)-7-4.5U

2、singweightedfeatures-8-4.6Carefullychosenparameterspace-8-4.6.1ImplementationofanEfficientEllipseDetectionAlgorithm-9-5.Limitations-9-6.Seealso-10-References-11-Accessories:-12--12-Houghtransform(FromWikipedia,thefreeencyclopedia)TheHoughtransformisafeatureextractiontechn

3、iqueusedinimageanalysis,computervision,anddigitalimageprocessing.[1]Thepurposeofthetechniqueistofindimperfectinstancesofobjectswithinacertainclassofshapesbyavotingprocedure.Thisvotingprocedureiscarriedoutinaparameterspace,fromwhichobjectcandidatesareobtainedaslocalmaximai

4、naso-calledaccumulatorspacethatisexplicitlyconstructedbythealgorithmforcomputingtheHoughtransform.TheclassicalHoughtransformwasconcernedwiththeidentificationoflinesintheimage,butlatertheHoughtransformhasbeenextendedtoidentifyingpositionsofarbitraryshapes,mostcommonlycircl

5、esorellipses.TheHoughtransformasitisuniversallyusedtodaywasinventedbyRichardDudaandPeterHartin1972,whocalledita"generalizedHoughtransform"[2]aftertherelated1962patentofPaulHough.[3]ThetransformwaspopularizedinthecomputervisioncommunitybyDanaH.Ballardthrougha1981journalart

6、icletitled"GeneralizingtheHoughtransformtodetectarbitraryshapes".1.TheoryInautomatedanalysisofdigitalimages,asubproblemoftenarisesofdetectingsimpleshapes,suchasstraightlines,circlesorellipses.Inmanycasesanedgedetectorcanbeusedasapre-processingstagetoobtainimagepointsorima

7、gepixelsthatareonthedesiredcurveintheimagespace.Duetoimperfectionsineithertheimagedataortheedgedetector,however,theremaybemissingpointsorpixelsonthedesiredcurvesaswellasspatialdeviationsbetweentheidealline/circle/ellipseandthenoisyedgepointsastheyareobtainedfromtheedgedet

8、ector.Forthesereasons,itisoftennon-trivialtogrouptheextractededgefeaturestoanappropriatesetoflin