同轴全息术测量粒子场的计算机模拟及实验研究

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1、西北工业大学硕士学位论文同轴全息术测量粒子场的计算机模拟及实验研究姓名：陈鹏飞申请学位级别：硕士专业：光学工程指导教师：赵建林20040301西北工业大学硕士学位论文ParticleMeasurementwithDigitalHolography：ComputationalSimulationandExperiment+AbstractInmanyfieldsofscienceandtechnology,itisveryimportanttoacquirethesize，positionandvelocityofparticlesordroplets．Thereareplent

2、yoftechniquestogettheseparameters．Ofallthetechniques，opticalin-lineholographyhassomeparticularadvantages：non-destructive，widesize—rangeofthemeasuredparticles，largedepthoffield，directreconstructionof3-Dparticlefield，highresolutionandsimpleset-up．DigitalholographyisanovelimagingtechniquewhichU

3、SeShigh-resolutionCCD-camerasashologramrecordingmediumandreconstructstheimagewithnumericalmethod．Itinvolvesopticalholography,computerscience，electronictechnologyanddigitalimageprocessing．Inrecentyears，particleanalysiswithdigitalin—lineholographyisanactiveresearchfield．Themaincontentsofthisth

4、esisare：(1)Twonumericalreconstructionmethods--DirectFouriertransformmethodandenvelopemethod，arepresented．ThesemethodsarededucedonthebaseofFresneldiffractionintegralformula．whichisundertheconditionthatparticlefieldisilluminatedbyplanewave．Inthecaseofsphericalwave，thenumericalreconstructionmet

5、hodsaresimilartothepreviousmethodsTheresultsindicatethattheenvelopemethodismoreeffectiveinactualapplication．Andtherecordingdistancelimitationsduetothestatedpixelnumber,pixelsizeandlaserwavelengtharediscussedindetail．(2)Computationalsimulationsonin—lineholographyofsingleparticle，multi-particl

6、einoneplaneandparticlefield(multi—layer)areperformed．Atechniquetofindthefocalplaneisgivenaccordingtothegray—gradientcurveoftheparticleimage．Animprovednumericalreconstructionmetllodisproposed．whichcaneliminatetheborderdiffraction．(3)Inmulti-particlesimulation，iftheparticlesarenottoodense，ther

7、econstructionimagesofparticlesareclear．Whentheparticlesdensityreachessomedegree，thedefinitionofthereconstructionimageswilldecreasealongwiththeparticlesdensitygrowing。Thisphenomenonisexplainedinthisthesis．(4)Instaticparticlefield(multi—layer)simulat