大视场中子孔径成像模拟与图像重建

《大视场中子孔径成像模拟与图像重建》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、LargefieldofneutronapertureimagingsimulationandimagereconstructionAThesisSubmittedtoChongqingUniversityinPartialFulfillmentoftheRequirementfortheDegreeofMasterofSicenceByXianyouWangSupervisor:Prof.ZhenyunFangMajor:ParticlePhysicsCollegeofmathematicsandphysicsChongq

2、ingUniversity,Chongqing,ChinaApril2008重庆大学硕士学位论文中文摘要摘要在中子孔径成像系统中,成像系统的参数决定了成像的质量。因此为了得到优化的系统参数，本文从工程应用条件出发利用Geant4建立了针孔成像模型，以及半影编码成像模型，并获得了半影编码成像的点扩展函数。然后分析了针孔成像与半影成像之间的优缺点。同时还根据建立的成像系统，模拟得出了中子源通过孔径所投影的像。其中通过半影孔所成像为编码像，需要进行解码处理。本文应用了两种线性解码算法对编码像进行了解码复原，从而验证了孔径成像系统的

3、可行性。本文的主要研究成果包括：①设计并建立中子针孔和半影成像模型，应用模型对成像过程进行仿真。②仿真并讨论了中子源随空间分布对系统点扩展函数的影响。③利用线性解码算法(维纳滤波法，Lucy-Richardson)对不同中子源形成的编码像进行了解码复原。关键词：中子针孔成像，点扩散函数，Geant4，维纳滤波法，Lucy-Richardson算法I重庆大学硕士学位论文英文摘要ABSTRACTIntheneutronapertureimagerysystem,theimagerysystemparameterhasdecide

4、dtheimageryquality.Thereforeinordertoobtainoptimizedthesystemparameter,thisarticleembarkedfromtheprojectapplicationconditionusingGeant4hasestablishedthepinholeimagerymodel,aswellasthepenumbracodeimagerymodel,andhasobtainedthepenumbracodeimagerypointspreadfunction.T

5、henwehaveanalyzedthedifferencebetweenthepinholeimageryandthepenumbraimagery.Simultaneouslywehaveobtainedtheprojectedimagingoftheneutronsourceaccordingtotheimagerysystem.Inadditiontheneutronthroughthepenumbraholeformedcodeimaging，whichneedtobedecoded.Inthisarticlewe

6、appliedtwokindoflineardecodingalgorithmtogettherestoredimaging,whichisthesourcedistribution.Thuswehaveconfirmedthefeasibilityoftheapertureimagerysystem.Themainresearchresultsthisarticle:(1)Thedesignandtheestablishmenttotheneutronpinholeandthepenumbraimagerymodel,th

7、enweappliedthemodeltosimulatetheimagingprocess.(2)Thesimulationanddiscussiontotheinfluenceofthesystempointspreadfunctionasthespatialdistributionchangedwiththeneutronsource.(3)Usingthelineardecodingalgorithm(wienerfilter,Lucy-Richardson)torestorethecodeimagingwhichf

8、ormedfromtheneutronsourcewithdifferentshapeanddifferentenergydistribution.Keywords:neutronpinholeimaging,pointspreadfunction,Geant4,wienerfiltera