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ID:57401321
大小:652.50 KB
页数:15页
时间:2020-08-18
《MATLAB实现的医学图像FBP算法课件.ppt》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、TheFilteredBackprojectionAlgorithminMATLABGregGallardo51:185FilteredBackprojectionAlgorithmMeasurethefamilyofprojectionsK=#ofprojections(angles),N=#ofrays(detectorsize)PerformFFT[]MultiplyFFT[]byFFT[].PerformIFFT[productfromstep3]Performbackprojectionas:1)Measurethefami
2、lyofprojections[R,Xp]=RADON(...)returnstwovariablesMatrixR–columnsaretheRadontransformfortheangles.RowsaredetectorpositionVectorXp-containingtheradialcoordinatescorrespondingtoeachrowofR.1)MeasurethefamilyofprojectionsFunctionparameterssize():getsNandKnextpow2():getwidt
3、hforFFT2)PerformFFT[]MATLABstandsforMATrixLABoratoryMatrixoperationsarefasterthanvisitingeachelementinaloop.3)MultiplyFFT[]byFFT[]BackprojectionfiltersShepp-Logan:Ram-Lakmultipliedbysincfunction(seeiradonhelp)Cosine:Ram-LakmultipliedbycosineHamming:Ram-LakmultipliedbyHa
4、mmingwindowHanning,Blackman,etc.3)MultiplyFFT[]byFFT[]Ram-Lak,Shepp-LoganandCosinefiltersinfrequencydomain3)MultiplyFFT[]byFFT[]FIRFilters.CommonlyusedWindowsFigurefrom“Discrete-TimeSignalProcessing”,Oppenheim&Schafer,Prentice-Hall3)MultiplyFFT[]byFFT[]RectangularBartle
5、tt(triangular)Hanning(vonHann)HammingBlackmanfrom“Discrete-TimeSignalProcessing”,Oppenheim&Schafer,Prentice-Hall3)MultiplyFFT[]byFFT[]3)MultiplyFFT[]byFFT[]3)MultiplyFFT[]byFFT[]Filterstep.Elementbyelementmultiplication4)IFFT[productfromstep3]5)PerformBackprojectionas:R
6、esultsResults
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