Digital Watermarking Technology And Application Research

With the rapid development of Internet and digital technology,digital productsbecome more and more popular,mainly because they can be transmitted conveniently,but the problem of copyright protection is also more and more serious.Theinapplicability of traditional information security technology for copyrights problempromotes the development of digital watermarking.Digital watermarking technologyembeds digital watermark in digital media that provides copyright proof for the ownerof digital media.Robustness and invisibility are two important features of digitalwatermark.The blind detection property can facilitate application of digitalwatermarking.This dissertation thoroughly studied the watermarking technology and theapplications.The main contributions are listed below:1.A robust digital watermarking scheme based on template matching is proposed.The digital watermark is embedded in the wavelet transform domain according to atemplate.This scheme realizes blind watermark extraction without any extrainformation.By sharpening the watermarked image before extraction,the precision ofthe extracted watermark is enhanced,thus the robustness of the watermark is improvedagainst image processing and lossy compression etc..2.A new scheme for embedding watermark in normalized feature area ispresented,that eliminates some problems in MIBIN (Moment Invariant Based ImageNormalization).MIBIN has been used in watermarking schemes to resist geometrictransform attacks,however,the stability of the normalized image and watermarkextraction can be affected by the embedded watermark,gray level histogram adjustment,and content removal etc.Thus the robustness of the digital watermark is damaged.FromMIBIN theory,some solutions to these problems are given in this scheme.3.A watermarking scheme based on SVM (Support Vector Machine) is presented,the robustness of the scheme comes from the good learning and generalization ability ofSVM,the watermark can be extracted without any auxiliary information.Using thesimilarity of digital watermark extraction and pattern recognition,this scheme gives methods for watermark embedding and extraction,which are suitable to SVMapplication,by analyzing the influence of kernel functions and their parameters onwatermark extraction.4.A digital video watermarking scheme with dual protection is presented,whichcan provide copyright proof by the watermark,and protect the video content directly bythe VRE (Video Reconstruction Error).From the video coding procedure,theinteraction between the watermark and the video is analyzed,and the mechanism ofproducing and elimination of VRE is obtained.This mechanism is used by the schemeto enhance the robustness of the watermark and to provide dual protection for the video.5.A storage centered online transaction architecture and corresponding protocolare proposed,which settle the storage problem of digital products and transactionrecords in the buyer-seller watermarking protocol.The architecture and the protocol canensure the security of the digital products and their transaction records,and make themeasy to be managed.At the same time,the boundaries between sub-protocols are clearer.6.The concept of multi-copy watermark space is given;and the model of optimalsearch for static target is improved,which is used in watermark space for setting upoptimal watermark extraction sequence.Multi-copy watermark scheme can enhance thecomprehensive robustness of the watermark,but it is uncertain which watermark copyexists after attacks,so the extraction time is quite long for an exhausting search.Theoptimal extraction sequence can make the expected extraction time minimal.