基于分?jǐn)?shù)傅立葉變換的圖像水印算法的研究.pdf

1、江南大學(xué)碩士學(xué)位論文基于分?jǐn)?shù)傅立葉變換的圖像水印算法的研究姓名：張貞凱申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：檢測(cè)技術(shù)與自動(dòng)化裝置指導(dǎo)教師：于鳳芹20070301AbstractWiththerapiddevelopmentofdigitaltechnologyandthewideapplicationofnetwork，theprotectionofcopyrightownershipbecomesmoreandmorenecessaryandimp

2、ortantTheinformationencryptionisnotenoughbecausethedocumentCanbecopiedanddistributedeasilyoncedeeryptedAsanewmethodagainstthefailureofencryptiondigitalwatermarkinghasbeenproposedasaneffectivewaytoprotecttheownershipofdig

3、italdocumentsInthispaper，digitalwatermarkingalgorithmsforimagebasedonthemultiplicityoffractionalFouriertransform(FRFT)areresearchedInordertoimprovethecomplexityofthealgorithmsforimageencryptionusingFRFTallalgorithmbasedo

4、nthemultiplicityofGeneratingSequenceofFRFTisproposedinthispaperWiththehelpofthemultiplicityofGeneratingSequencethreekemelfunctionsofFRFTareproducedtobuildthreedifferentFlU叮operatorsAndthethreeGeneratingSequencestransform

5、orders，randommatrixesforphaseencodingareusedaseneryptionkeysinthealgorithmThecodedimageistransformedthreetimesbydifferentFRFTwithdifferentkernelfunctionsinordertoencrypttheimageAsthetransformtimesofFRFTincreasethecomplex

6、ityofthealgorithmenhancesResearchtowardsrobustwatermarkingbasedonFRFTisthemainworkofthispaperAnovelwatermarkingembeddinganddetectingalgorithmforimageisproposed，whichUseSachirpsignalasthewatermarksignalandembedsitinthedom

7、ainofthefractionalFouriertransformoftheimageThatis，thiswayisthecombinationofinformationencryptionanddigitalwatermarkingAftertheoriginalimageistransformedbytwodimensionalFⅪ可thewatermarkisaddedtosomespecialcoefficientsinth

8、eFRFTdomainSincethetransformorderandtheembeddingpositionareusedastheencryptionkeys，thismethodhasagoodsecurityAccordingtothespecialpropertyofchirpsignalsthatachirpCanproduceastrongimpulsewhenthechirpsignalhasthesamesweepr

9、ateastheFRFTwecandetectthewatermarkconvenientlyManyattackexperimentshavebeenperformedtodemonstratetheeffectivenessofthealgorithmTheresultshaveshowthattheproposedaigofithmnotonlyisofgoodimperceptibilityandsecurityandisver

10、yrobusttoJPEGcompressionandnoiseattacks，butalsoCan’tprovideprotectionunderthegeometricattacks，suchasrotationandthetranslationTwoalgorithmsarepresentedinordertoimprovethealgorithmFirst，accordingtotherelationshipbetweenFou

11、rierMellintransformandgeometricattacks，achirpsignalandatemplateareembeddedinthedisereteFRFTdomainanddiscreteFouriertransform(DFT)domainrespectivelyThetemplateintheDFTdomainCanbeusedtocompensateforthelossesoftheimagesbrou