简介:Tomakeaudiowatermarkingaccomplishbothcopyrightprotectionandcontentauthenticationwithlocalization,anovelmultipurposeaudiowatermarkingschemeisproposedinthispaper.Thezero-watermarkingideaisintroducedintothedesignofrobustwatermarkingalgorithmtoensurethetransparencyandtoavoidtheinterferencebetweentherobustwatermarkandthesemi-fragilewatermark.ThepropertyofnaturalaudiothattheVQindicesofDWT-DCTcoefficientsamongneighboringframestendtobeverysimilarisutilizedtoextractessentialfeaturefromthehostaudio,whichisthenusedforwatermarkex-traction.And,thechaoticmappingbasedsemi-fragilewatermarkisembeddedinthedetailwaveletcoefficientsbasedontheinstantaneousmixingmodeloftheindependentcomponentanalysis(ICA)system.Boththerobustandsemi-fragilewatermarkscanbeextractedblindlyandthesemi-fragilewatermarkingalgorithmcanlocalizethetamperingaccurately.Simulationresultsdemonstratetheeffectivenessofouralgorithmintermsoftransparency,security,robustnessandtamperinglocalizationability.
简介:Anaudiorecoveringmethodofspread-spectrumhiddeninformationisproposedbasedongeneticalgorithm.Inthismethodtheembeddedsequencelengthisconfirmedfirstly,thenthebestestimatedsequencewiththeconfirmedlengthisgotbygeneticalgorithm,finallytheconfidentialmessagehiddeninstego-audiocanberecovered.Usingthisapproach,thehiddeninformationcanberecoveredwithoutanyinformationfromthetransmitter.ThepresentedmethodhasbeenimplementedonPC,andtheexperimentalresultsshowthattheaveragerecoveringcorrectrateishigherthan90%.
简介:Wereportthefabricationprocessofpiezoelectriccellulosepaperandtheenhancementmethodofitspiezoelectricproperty.Stretchingmethodwithdifferentwet-drawingratioswasintroducedtoincreasethepiezoelectricpropertyofcellulosepaperduringregenerationprocess.ItisobservedthattheYoung’smodulusandthepiezoelectricchargeconstantsareverydependentonthedrawingratioandthedirectionofnanofibrilsofpiezoelectricpaper.Usingtheenhancedpiezoelectricproperty,weprovethattheflexibleregeneratedpiezoelectriccellulosecanbeappliedtothepotentialacousticapplicationssuchasthinpiezoelectricpaperspeaker.