简介:VisualimagesensorisdevelopedtodetecttheweldpoolimagesinpulsedMIGwelding.Anexposurecontroller,whichiscomposedofthemodulesofthevoltagetransforming,theexposureparameterspresetting,thecomplexprogrammablelogicdevice(CPLD)basedlogiccontrolling,exposuresignalprocessing,thearcstatedetecting,themechanicalirisdrivingandsoon,isdesignedatfirst.Then,avisualimagesensorconsistsofanordinaryCCDcamera,opticalsystemandexposurecontrollerisestablished.Theexposuresynchroniccontrollogicisdescribedwithvery-high-speedintegratedcircuithardwaredescriptionlanguage(VHDL)andprogrammedwithCPLD,todetectweldpoolimagesatthestageofbasecurrentinpulsedMIGwelding.Finally,bothbeadonplateweldingandVgroovefilledweldingarecarriedout,clearandconsistentweldpoolimagesareacquired.
简介:Inthispaper,theX-raynondestructivetestmethodofsmalldefectsinprecisionweldmentswithcomplexstructurewaspresented.Toresolvethedifficultyofdefectsegmentationinvariablegreyimage,theimageprocessingbasedonVisualBasicprogrammingmethodwasadopted.ThemethodsofautomaticcontrastandpartialgreystretchwereusedtoenhancetheX-raydetectionimagewhichhasrelativelylowcontrast,thenautomaticthresholdmethodwascarriedouttosegmentthetwohighintensityzones,andweldzoneswhichcontainthesmalldefectswasextracted.Smoothingandsharpenprocessingwereproceededontheextractedweldzones,andsmalldefectsinX-raydetectionimageofweldmentswithcomplexstructureweresegmentedbyusingthemethodofbackgroundsubtractionintheend.Theeffectsofrasterwereeliminated,andbecauseofthattheimageprocessingwasonlyproceededontheextractedweldzones,thecalculatedspeedusingtheaboveprovidedalgorithmwasimproved.
简介:Imagesensorhasbeenoneofthekeytechnologiesinintellectualizedroboticswelding.Edgedetectionplaysanimportantrolewhenthevisiontechnologyisappliedinintellectualizedweldingroboticstechnologies.Thereareallkindsofnoisesinweldingenvironment.Thealgorithmsincommonusecannotbeappliedtotherecognitionofweldingenvironmentdirectly.Theedgeofimagescanbefellintofourtypes.Theweldimagesareclassifiedbythecharacteristicofweldingenvironmentinthispaper.Thispaperanalyzessomealgorithmsofedgedetectionaccordingtothecharacterofweldingimage,somerelativeadvantagesanddisadvantagesarepointedoutwhenthesealgorithmsareusedinthisfield,andsomesuggestionsaregiven.Thefeatureextractionofweldseamandweldpoolaretwotypicalproblemsintherealizationofintellectualizedwelding.Theiredgefeaturesareextractedandtheresultsshowtheapplicabilityofdifferentedgedetectors.Thetradeoffbetweenprecisionandcalculatedtimeisalsoconsideredfordifferentapplication.
简介:Computervisionhascomeintousedinthefieldsofweldingprocesscontrolandautomation.Inordertoimproveprecisionandrapidityofweldingimageprocessing,anovelmethodbasedonfractaltheoryhasbeenputforwardinthispaper.Comparedwithtraditionalmethods,theimageispreliminarilyprocessedinthemacroscopicregionsthenthoroughlyanalyzedinthemicroscopicregionsinthenewmethod.Withwhich,animageisdivideduptosomeregionsaccordingtothedifferentfractalcharactersofimageedge,andthefuzzyregionsincludingimageedgesaredetectedout,thenimageedgesareidentifiedwithSobeloperatorandcurvedbyLSM(LeaseSquareMethod).Sincethedatatobeprocessedhavebeendecreasedandthenoiseofimagehasbeenreduced,ithasbeentestifiedthroughexperimentsthatedgesofweldseamorweldpoolcouldberecognizedcorrectlyandquickly.
简介:Adual-beamelectronicspecklepatterninterferometry(ESPI)systemwasadoptedtogetspecklepatternsforthemeasurementofweldingdynamicdisplacementfields.Themathematicalmodelofthissystemwasdescribed,basedonwhichmethodsoftheESPIpatternimageprocessingwerediscussed.Graytransformationandhistogramequalizationwereusedtoenhancethecontrastofspecklepatterns.Adiscretecosineimageprocessingmethodwascarriedoutandanexponentlow-passfilterwaschosentoreducemultiplicativenoiseinspecklepatterns.Specklegrainnoisecanbeeliminatedeffectivelyaftertheseprocesses.
简介:ThelateralwaveinultrasonicTOFD(timeofflightdiffraction)imagehasatailintransittime,whichdisturbsthedetectionandevaluationofshallowwelddefect.Meanwhile,thelateralwaveandback-wallechothatactasbackgroundaddredundantdataindigitalimageprocessing.Inordertoseparatedefectwavefromlateralwaveandpreparethewayforfollowingimageprocessing,analgorithmofbackgroundremovalmethodnamedasmean-subtractionisdeveloped.Basedonthis,animprovedmethodbystatisticoftheenergydistributionintheimageisproposed.Theresultsshowthatbychoosingproperthresholdvalueaccordingtotheaxialenergydistributionoftheimage,thebackgroundcanberemovedautomaticallyandthedefectsectionbecomespredominant.Meanwhile,diffractivewaveofshallowwelddefectcanbeseparatedfromlateralwaveeffectively.
简介:Obtainingtheimageofmoltenpoolaluminumalloy'stungsteninertgas(TIG)weldingbecomesachallengingproblemintheweldingfield.Inthispaper,abran-newopticalsensorbasedanalyzingthelightspectrumwasdesigned,andtheclearimageofthemoltenpoolduringthealuminumalloy'sweldingusingthecommonindustrialCCDcamerawasobtained.Andwiththenewalgorithmprovidedbymyself,thedesirablecharacteristicparametersofthemoltenpoolofaluminumalloy'sweldingwereobtained,anditprovidesagoodbaseforadvancedmonitorweldingquality.
简介:AnexperimentalsetupofacquiringthecoaxialvisualimageofthemoltenpoolandkeyholeinhighpowerNd:YAGlaserweldingisintroducedinthispaper.Itisoneofthemostdifficultproblemsinacquiringcoaxialimagethatthecoaxialimagingsignalofmoltenpoolandkeyholemustbeseparatedfromthelaserbeamwithhighpower.Thisproblemwasresolvedbydesigningadichroiticspectroscope.Thecharacteristicsofimagingsignalwereanalyzedandthecoaxialimageofmoltenpoolandkeyholewasacquired.Asmoothingfilterandahomomorphicfilterweredesignedtoremovethelowfrequencynoiseandtoenhancetheimageaccordingtothecharacteristicsofimagingsignal.Atlast,edgesofmoltenpoolandkeyholeweredetectedandextractedbasedonimagesegmentationwiththreshold.