資源描述：
《錐束螺旋CT的迭代算法研究》由會員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫。
1、中北大學(xué)碩士學(xué)位論文錐束螺旋CT的迭代算法研究姓名：薛震申請學(xué)位級別：碩士專業(yè)：應(yīng)用數(shù)學(xué)指導(dǎo)教師：潘晉孝20090425中北大學(xué)碩士學(xué)位論文AbstractComputedTomography(CT)isatechnologywithwhichwecanknowthestructureofanobjectinthewayofnon．destruction．UptonOWithasbeenusedwidelyinfieldsofsuchasmedicaldiagnosis．nondestructiveexamination，andaeronauticsandastr
2、onauticsetc．Cone—beamCThasmuchadvantageover2Dparallel．beamandfan。beamCTintheaspectsofspeedinobtainingdata，spatialresolutionandtheutilizationratioofrays．NowCTincommerceareturningtousingcone．beamCT．Helicalcone．beamCT-thecone．beamCTwithhelicalscanningpath，hasbeenknownforusinglessX·rays，s
3、canningfastwithlargevolume．highaccuracyofreconstruction．SoithasbecomeahottopicinthefieldofCTimagereconstruction．Atpresenttheresearchonreconstructionalgorithmsofhelicalcone．beamCTisgenerallybasedonanalyticalgorithms，andthesemethodsusuallyneedcompleteprojectiondata．Inpracticecompletepro
4、jectiondatacannotbeobtainedoutofobjectivecause，SOanalyticmethodsfailinthiscase．IterativealgorithmshavegottenmoreandmoreattentionforitCanreconstructimagessimplyandeffectivelyandCanreconstructimageswitIlincompleteprojectiondata．Someexploratorystudyhasbeenissuedonhelicalcone。beaminthisPa
5、Der．Themaincontextisasfollows：Firstly,afastandreal—timemethodofobtainingprojectionmatrixisproposedaccordingtothecharacteristicofhelicalcone．beamCT．Theanalysisoncomplexityisdone．Theeffectivenessofproposedalgorithmsisprovedbysomeexperiments．Secondly,theeffectofpitchonreconstructedresult
6、isgoRenthroughreconstructingimageswithprojectiondataindifferentpitches．TheexperimentalresultsshowthatthepitchCanusuallybechosenas0．5．1．5timestheheightofdetectorontheconditionthatcone．beameffectiSnotobvious．Thusthereconstructedspeedcanbefastened．theamountofradiationcallbereduced，andbet
7、terreconstructedresultscanbeobtained．Lastly,theiterativealgorithmsaredonewiththeprojectiondataincaseofsparseandsight—limited．Theexperimentalresultsshowthatbetterimagescanstillbegottenbyusingiterativereconstructionalgorithmwithincompleteprojectiondata．Ontheconditionthattheamountofproje
8、ction
