二值图象中的密写和密写分析

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1、上海大学博士学位论文二值图象中的密写和密写分析姓名：梁光兰申请学位级别：博士专业：通信与信息系统指导教师：王朔中20070701上海大学博上学位论文．二值图象中的密写和密写分析AbstractWiththeaccelerationoftheglobalinformationdigitization，numerousbinaryimagesarewidelyusedineverydaylifebecauseoftheconvenientstorageandeffortlessaccess．Therefore，hidingdatainbin

2、aryimagesforannotation，authentication，andcopyrightprotectionisingreatdemand．However,datahidinginbinaryimagesisachallengingtaskbecauseofthelackofredundancyinthecarrier．Arbitrarilyflippingthepixelvaluescancausenoticeablenoise．Inthisdissertation，withadetailedsurveyofthecurr

3、entlyavailabledatahidingmethods，wehavecarriedoutsomeexplorationondatahidinginbinaryimages．ThemainworkiSsummarizedasfollows：1．Unlikethepreviousblock-basedmethodsfordatahiding，weproposeanovelmethodforhidingarelativelylargeamountofdatadirectlyintheboundarypixelsofabinaryima

4、ge．Becauseallsecretdataareinsertedonboundaries，goodinvisibilityisassured．Thecentralpartoftheschemeisthetwosetsofrules，onefordatadependentembedding，andtheotherfordataindependentembedding．Theserulesaredesignedtoensurecorrectidentificationoftheembeddedinformationindataextra

5、ction．Inotherwords，theeligibilitystatusoftheboundarypixelsisnotaffectedbydataembeddingthereforetheoriginalcarrierimageisnotneededinextraction．2．Weintroduceahighcapacityreversibledatahidingmethodforbinaryimages．Thismethodisbasedonthecorrelationbetweentheboundarypixelsandi

6、tsimmediateneighbourhood．Eachboundarypixelsatisfyingcertainconditionsisassignedaflagbit．ItisshownthatthesequenceofallflagbitscontainsmoreZerOSthanonesthereforeislosslesslycompressible．Thecreatedspacebythecompressionisusedtocarrysecretmessagebits．Theoriginalbinaryimagecan

7、berestoredwithouterrorwhiletheembeddedinformationisextracted．Experimentalresults上海人学博上学位论文二值图象中的密写和密写分析demonstratevalidityandfeasibilityoftheproposedmethod．3．Asteganalyticalschemeisproposedagainstblock—baseddatahidingingrayimages，inwhichthechangeinstatisticalcharacterist

8、iccausedbyinformationhidingisusedtodetectthepresenceofsecretmessage．Block—baseddatahidingproceduremanip