最新嵌入机密讯息於数位影像及其压缩码之技术-药学医学精品资料.ppt

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1、最新嵌入机密讯息於数位影像及其压缩码之技术-药学医学精品资料Motivation-datahiding(1/4)SenderReceiverPublicnetworkInformationIllegaluser2021/8/22Motivation-datahiding(2/4)CryptographySenderReceiverPlaintextEncryptionalgorithmDecryptionalgorithmPlaintextCiphertextPublicnetworkEncryptionkeyDecrypti

2、onkeyMeaningless&distorted2021/8/23PartI:embeddingsecretsindigitalimagesImagehiding:hidingmultiple,relatively-largesecretimagesintoarelatively-smallcoverimage2021/8/27ImagehidingSecretimageCoverimageStegoimageExtractedsecretimage●ExtractedsecretimagewithAcceptablequa

3、lity●Stego-imagewithhighquality●HighhidingcapacityGoals●Compressionmethod●ModulussubstitutionTechniquesVectorquantization2021/8/28Vectorquantization(VQ)EuclideandistanceX■Howtogeneratearepresentativecodebook■HowtosearchtheclosestcodewordTwo-codebookcombinationThree-

4、phaseblockmatching2021/8/29TwocodebookcombinationThecovercodebookThedifferencecodebookCoverimageSecretimage01...N-2N-1(43,57,…,40)LBGclustering(k-meansclustering)Differenceimage01...M-2M-1(-5,6,…,10)LBGclustering(k-meansclustering)2021/8/210Three-phaseblockmatchingjkind

5、exjindexk0indexj,0indexk,1j010k1indexj,1indexk,3j111k3Secretimage2021/8/211EmbeddingLSBsofcoverimageThedifferencecodebookThecompressedindicesParametersTheindicesofchoseninitialvectors(covercodebook)ModulussubstitutionqLSBs(q=2)40:0010100039:00100111Hiddenbits:3(11)32103

6、21001111+3-12021/8/212Experimentalresults(1/3)TestimagesBaboonLenaPepperTiffanySceneJet2021/8/213Experimentalresults(2/3)Hu’sschemeTheproposedschemeWang-Tsai’sschemeEmbedasecretimageintoacoverimage(i.e.,Baboon)ofthesamesizeThePSNRsofthestegoimagesThePSNRsoftheextracteds

7、ecretimages2021/8/214Experimentalresults(3/3)coverimageThefirstsecretimageThesecondsecretimageHidemultipleimagesoflargesizeintoasmallcoverimageMethodsThestegoimageThefirstextractedsecretimageThesecondextractedsecretimageHu’sscheme48.8628.9228.18WangandTsai’sscheme37.252

8、9.5531.11Theproposedscheme41.0533.6733.81Hu’sschemeTheproposedschemeWang-Tsai’sscheme2021/8/215PartII:embeddin