光专业图像重建中的相移数字全息大学毕业论文英文文献翻译及原文Word格式.docx
- 文档编号:12936746
- 上传时间:2022-09-30
- 格式:DOCX
- 页数:20
- 大小:475.90KB
光专业图像重建中的相移数字全息大学毕业论文英文文献翻译及原文Word格式.docx
《光专业图像重建中的相移数字全息大学毕业论文英文文献翻译及原文Word格式.docx》由会员分享,可在线阅读,更多相关《光专业图像重建中的相移数字全息大学毕业论文英文文献翻译及原文Word格式.docx(20页珍藏版)》请在冰豆网上搜索。
图像重建中的相移数字全息
文献、资料英文题目:
文献、资料来源:
文献、资料发表(出版)日期:
院(部):
专业:
光学
班级:
姓名:
学号:
指导教师:
翻译日期:
2017.02.14
专业英语
专业光学
研究生部
专业英语考核
年级:
学院:
姓名:
学号:
专业:
光学
文献原文:
Title:
Phase-shiftingdigitalholographyinimagereconstruction
Abstract:
Aphase-shiftingdigitalholographyschemedevelopedtoinvestigateinternaldefectsinartworksisdescribed.Phase-shiftingisutilizedtoobtainaclearreconstructedobjectwavefromaroughsurfacetexture.Areverse-transformalgorithmisemployedtoreconstructtheobjectwaveonitsoriginalpositionofunknowndistanceortheimagingpositionfromtheobjectwaveinformationontheholographicplane.Togettheclearestreconstructiontheexactregistrationoftheunknowndistanceisdeterminedbyapplyingtheintensitysumastheauto-focusingfunction.Thespatialresolutionofthereconstructionimageisalsoinvestigatedforavarietyofaffectingfactors.Laboratoryresultsofreconstructionimagesunderdeformationarepresented.
Keywords:
holographicinterferometry,digitalholography,phase-shiftingtechnique,reverse-transformalgorithm,auto-focusingfunction,spatialresolution.
1Introduction
Differentmethodsofholographicinterferometryrelatedtechniqueshavebeenusedeffectivelyfordefectvisualisationinartworkdiagnosis.Physicalreconstructionofrecordedwavefieldsthoughisoflimitedapplicabilityforon-fieldorremoteapplicationsusuallyrequiredinartconservationenvironments.DigitalcounterpartsexplorednowadaystorecordtheinterferencebetweenanobjectanditsreferenceonCCDandreconstructtherecordnumericallyarebettersuitedforfielduse.Howevertheydonotprovidetheessentialspatialresolutionforcleanobjectreconstructionanddefectdetection,bothcriticalinartworkdiagnosticassessment.Towardsthisgoal,thisstudyaimsatovercomingtheabovelimitationsandexpandingtheuseofsuchtechniquesinthefieldofartworksconservation.
Aprincipalproblemindigitalholographyofartworksistoobtainaclearreconstruction.Toaccomplishthisthefollowingproblemsshouldbeaddressed:
(1)needofaproperalgorithmforthereconstructionofrecordedimages,
(2)removaloreliminationofspecklenoiseinthereconstructedimageandphasemap,(3)determinationoftheactualregistrationdistance,(4)improvementofspatialresolutionofthereconstructedimage.
Thefirsttwoproblemsisreferredtoasreconstructionalgorithms.Thesealgorithmscanbedividedintotwocategories.OnerealizesreconstructionfromasinglehologramasforexampletheFresnelalgorithmandtheconvolutionalgorithm.Suchalgorithmsonlyrequireasinglehologramandaresuitablefordynamicmeasurements,butthezero-orderspeckleandtheeffectofthereferencebeamarenotthoroughlyremoved.Thesecondcombinesthephase-shiftingtechniqueanddigitalholographytogethertoproduceimagereconstruction.Itsimportantadvantageistheabilitytoeliminatecompletelytheeffectofthereferencebeam,soitcangetaclearreconstructedimage.Indigitalholographyofartworks,mostoftheinvestigatedobjectshaveacoarsesurfaceandbigslopechangingsothatthespatialphase-shiftingtechniqueisunsuited.Therefore,evenifthetemporalphase-shiftingtechniqueisimproperfordynamictesting,itisappliedwidely.Inthisapproach,thefirststepusesaphase-shiftingtechniquetorecordtheobjectwaveontheholographicplate.Thenthereconstructionobjectwavecanbecalculatedatitsoriginalorimagingposition.Towardsthisgoalweproposeareconstructionalgorithmbasedonareverse-transformalgorithm,whichaccordswiththenotionofthedigitalholographyinprincipleandalsoproducesgoodreconstructionresults.
Inthereconstructionprocess,iftheregistrationdistanceusedhasabigdifferencewithitsactualvalue,thereconstructedimagewillbefuzzy.Inafirstapproximation,thisdistancecanbemeasuredintheopticaltestingsystemorestimatedbytheclarityobtainedinthereconstructedimage,butsuchapproacheslackaccuracyandstandardization.Thispaperproposedamethodtodeterminetheexactregistrationdistance,whichappliestheintensitysumofthereconstructionimageastheevaluatingfunctioninordertodeterminethetruevalue.Improvingthereconstruction
spatialresolutionisanimportantproblemworthaddressing.
2Reconstructionbasedonphase-shiftingdigitalholography
Therelationshipbetweentheobject,hologramandreconstructedimageisshownFig.1,wherexandydenotethecoordinatesoftheobjectplane,
and
thehologramplane,and
thereconstructionplane,distheregistrationdistance,
isthereconstructiondistance.
Indigitalholography,therecordingCCDisplacedonthe
-
planeinorder
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 专业 图像 重建 中的 相移 数字 全息 大学毕业 论文 英文 文献 翻译 原文
![提示](https://static.bdocx.com/images/bang_tan.gif)