Application
Accordingtotheapplicationfield,digitalwatermarkingcanbedividedinto:
①Robustwatermarking.Usuallyusedforcopyrightprotectionofdigitizedimages,videos,audiosorelectronicdocuments.Thespecificinformationrepresentingtheidentityofthecopyrightowner,suchasaparagraphoftext,logo,serialnumber,etc.,isembeddedinadigitalproductinacertainway.Whenacopyrightdisputeoccurs,thedigitalwatermarkisextractedthroughthecorrespondingalgorithmtoverifytheownershipofthecopyrightandensureThelegitimateinterestsofcopyrightownersavoidthethreatofillegalpiracy.
②Fragilewatermark.Alsoknownasfragilewatermark.Usuallyusedfordataintegrityprotection.Whenthecontentofthedatachanges,thefragilewatermarkwillchangeaccordingly,sothattheintegrityofthedatacanbeverified.
③Markthewatermark.Usuallyusedtoindicatedatacontent.
Carrier
Accordingtotheloadedcarrier,digitalwatermarkscanbedividedinto:
①Imagewatermarks.Thewatermarkloadedontheimagedata.
②Videowatermark.Thewatermarkloadedonthevideodata.
③Audiowatermark.Thewatermarkloadedontheaudiodata.
④Softwarewatermark.Thewatermarkloadedonthesoftware.
⑤Documentwatermark.Thewatermarkloadedonthedocument.
Methods
Accordingtotheloadingmethod,digitalwatermarkscanbedividedinto:
①Spatialdomainwatermarks.Loadthewatermarkdirectlyontothecarrierdata.
②Transformationdomainwatermark.LoadthewatermarkonthedatainthetransformdomainsuchastheFouriertransformdomainandthewavelettransformdomainofthecarrierdata.
Features
Themainfeaturesofdigitalwatermarkingare:
①Transparency.Thewatermarkandtheoriginaldataarecloselyintegratedandhidden.Theexistenceofthewatermarkcannotdestroytheappreciationvalueandusevalueoftheoriginaldata.
②Robustness.Theabilitytodetectwatermarksafterroutineprocessingoperationssuchaslossycompression,recording,printing,scanning,rotation,andtranslation.
③Security.Theabilitytoresistunauthorizeddeletion,embedding,anddetectionbyattackers.Mainlyusedforinformationintegrityauthentication.