英文文献及翻译：级联迭代傅里叶变换算法在光学安全中的应用.doc

《英文文献及翻译：级联迭代傅里叶变换算法在光学安全中的应用.doc》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、14河南科技大学本科毕业设计（论文）AcascadediterativeFouriertransformalgorithmforopticalsecurityapplicationsAbstract:AcascadediterativeFouriertransform(CIFT)algorithmispresentedforopticalsecurityapplications.Twophase-masksaredesignedandlocatedintheinputandtheFourierdomainsofa4-fcorrelatorrespectively,

2、inordertoimplementtheopticalencryptionorauthenticityverification.Comparedwithpreviousmethods,theproposedalgorithmemploysanimprovedsearchingstrategy:modifyingthephase-distributionsofbothmaskssynchronouslyaswellasenlargingthesearchingspace.Computersimulationsshowthatthealgorithmresultsi

3、nmuchfasterconvergenceandbetterimagequalityfortherecoveredimage.Eachofthesemasksisassignedtodifferentperson.Therefore,thedecryptedimagecanbeobtainedonlywhenallthesemasksareunderauthorization.Thiskey-assignmentstrategymayreducetheriskofbeingintruded.Keywords:Opticalsecurity–opticalencr

4、yption–cascadediterativeFouriertransformalgorithm1.IntroductionOpticaltechniqueshaveshowngreatpotentialinthefieldofinformationsecurityapplications.RecentlyRéfrégierandJavidiproposedanoveldouble-random-phaseencodingtechnique,whichencodesaprimaryimageintoastationarywhitenoise.Thistechni

5、quewasalsousedtoencryptinformationinthefractionalFourierdomainandtostoreencryptedinformationholographically.Phaseencodingtechniqueswerealsoproposedforopticalauthenticityverification.WangetalandLietalproposedanothermethodforopticalencryptionandauthenticityverification.Unlikethetechniqu

6、esmentionedabove,thismethodencryptsinformationcompletelyintoaphasemask,whichislocatedineithertheinputortheFourierdomainofa4-fcorrelator.Forinstance,giventhepredefinitionsofasignificantimagef(x,y)asthedesiredoutputandaphase-distributionexp{jb(u,v)}intheFourierdomain,it’seasytooptimizet

7、heotherphasefunctionexp{jp(x,y)}withamodifiedprojectionontoconstraintsets(POCS)algorithm[10].Thereforetheimagef(x,y)isencodedsuccessfullyintoexp{jp(x,y)}withtheaidofexp{jb(u,v)}.Inotherwords,thefixedphaseexp{jb(u,v)}servesasthelockwhiletheretrievedphaseexp{jp(x,y)}servesasthekeyofthes

8、ecuri