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一种新颖的用于图像内容认证、定位和恢复的半脆弱数字水印算法研究.docx

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一种新颖的用于图像内容认证、定位和恢复的半脆弱数字水印算法研究 Introduction Thedemandforsecureandauthenticvisualcontentintoday'sdigitalageisontherise.Toovercomethethreatofunauthorizedalterationofvisualcontent,manyresearchershaveproposedvarioustechniquestoembedadigitalwatermarkwithinimagestoprovidecopyrightprotection,contentauthentication,andtamperdetection.Inthispaper,wepresentanovelsemi-fragiledigitalwatermarkalgorithmthatcanbeusedforimagecontentauthentication,localization,andrecovery. Background Digitalwatermarkingisawidelyresearchedfieldthataimstoprovideprotectiontodigitalmediabyaddinginvisiblemarksthatareuniquetotheowner.Watermarkingcanbeachievedthroughvariousmethods,includingspatialandtransformdomaintechniques.Thespatialdomainwatermarksalterthepixelvaluesbyaddingorsubtractingavaluetothepixelintensities.Incontrast,transformdomaintechniquesaltertheimagebymodifyingtheimagefrequencycomponentusingdomain-specifictransformationslikeFourier,DCT,andWavelets. Semi-fragilewatermarkingisatechniquethatcombinesboththecharacteristicsoffragileandrobustwatermarks.Infragilewatermarking,evenminorchangestotheimagedestroythewatermark,whereasinrobustwatermarking,thewatermarkremainsintactevenaftermajormodificationstotheimage.Semi-fragilewatermarksaredesignedtobeabletoidentifychangesintheimageandprovidetamperdetectionwhilealsosurvivingsomeminormodifications. Methodology Ourproposedsemi-fragiledigitalwatermarkalgorithmconsistsoftheembeddingandextractionphases.Intheembeddingphase,thealgorithmusesaWavelet-basedtransformdomaintechniquetoembedawatermarkimageintothehostimage.ThewatermarkisgeneratedbyscramblingarandombinarysequenceusingArnoldTransform.Thescrambledbinaryisthenusedtogenerateawatermarkimagebyaddingafixedvaluetothehostimage'spixelintensities'Waveletcomponents. Incomparison,theextractionphaseinvolvesdetectingthewatermarkandidentifyingthetamperedregionsintheimage.ThewatermarkisretrievedbyusingthesameArnoldtransformusedintheembeddingphase.Theembeddedwatermarkbitsarethenextractedbyanalyzingthedifferencesbetweenth