基于DCT的彩色图像双水印算法

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1、西南交通大学硕士学位论文基于DCT的彩色图像双水印算法姓名：李艳玲申请学位级别：硕士专业：计算机应用指导教师：张翠芳20070501西南交通大学硕士研究生学位论文第1

2、页AbstractDigitalmultimediahasbeenbecomeamainwayforinformationcommunicationalongwiththewideuseofnetwork．Thus．howtoprotecttheintellectualpropertyfordigitalmediabecomesallinterestingissueoninte

3、rnational．AsanimportantembranchmentofinR脚a虹onhiding,watermarkiseffectivemeansforprotectingcopyright．Itcanidentifythesignal’SiI她鲫ityorpropertythroughembeddingadditionalinformationintomultimediasignal．Watermarkappliedincolorimageisresearchedjnthispaper．Firstly,backgroundandco

4、nditionsaboutwatermarkisintroduced．Definition,sortsandapplicationsalealsotalkedabout．Somekeytechnologiesaboutimagewatermarksuchasencrypting,colorspace，transformdomainareintroducedindetail．Throughstudyingexistingwatermarktechnologies，anewdouble-watermarkingalgorithmbasedonDC

5、Tforcolorimageispresented幻authenticatepropertyandmaketracksforpeddler．Bothabinaryimageandalogistiechaoticsequenceareusedaswatermarkinthisalgorithm．ARertransformedtheoriginalimagefromRGBtoYCbCr,thebinaryimagewhichhadbeenencryptedthroughArnoldtransformingis锄beddedintotheDCTlo

6、wfrequencycoefficientoftheYcomponentoftheimage．Andthen，consideringtheHVScharacteristicsofhumaneyes，thelogisticchaoticsequenceisadaptiveembeddcdintotheDCTACcoefficientoftheCbcomponentoftheimage．Experimentalresultsshowthatwatermarksareinvisibleafterembeddedintoimageandarerobu

7、stagainstvarioussignalprocessingsuchascompressing,zooming,croppingrotating，andnoiseadding．Butwhencolorimageischangedintograylevelimage,thelogisticchaoticsequenceCannotbefoundout．Toavoidthelogisticwatermarkislost,alittleimprovementiscomeuptothealgorithm．Boththebinaryimageand

8、thelogisticchaoticsequenceareembeddedrespectivelyintotheDCTlowfrequencycoefficientandAC西南交通大学硕士研究生学位论文第1II页coefficientoftheYCOmponentoftheimage．Experimentalresultsshowthatafterimprovementthewatermarksaresilllinvisibleandrobust，More,over,whenorigillatcolorimageischangedintog

9、raylevelimage,bothofthewaWn-narksalestillexistent．Soalterimprovement,thealgorithmc