Research On Robust Digital Image Watermarking Techniques

Nowadays, with the rapid development of electronic technology and computer technology, it iseasy and convenient to spread copy and store the digital multimedia content by its widespreaddissemination. People’s attitudes and lifestyle is change by the development of digital technology,most people can find all forms of information they want through the Internet, then they candownload, dissemination, store and tamper with the digital information, which makes securityissues of digital multimedia content become an outstanding problem, such as copyrightprotection of digital content and the problem of transferring-security. How to ensure that digitalcontent will not be illegal read. How to ensure that digital multimedia content will not betampered with and pirated, and how to protect the legitimate rights of its copyright owner. Allthese issues have become the key subjects being mutual concern and expecting resolution ofacademia and industry. In this context, digital watermarking technology came into being.Digital watermarking is a technique of embedding the tailor-made, invisible marking information(such as text, picture, audio, video and so on) into the digital image, audio files and video by acertain algorithm, to define copyright owner, authenticate the digital content, mark illegalpurchaser, control copy, realize ownership certification and track the infringement operation.Digital watermarking technique is not only a scheme for protecting the illegal right of digitalworks, but also applicable in many fields. Now, it has been widely applied in detecting andtracking data, monitoring and controlling broadcast, payment-services on the internet andcertification in electronic commerce. This paper researches the digital watermarking techniqueand proposes a robust watermarking scheme, based on learning from former researchers. Themain of this paper include the following:First of all, a general overview of the digital watermarking’s model, characteristics, classificationand attack was given, and consensus evaluating indicators of watermarking used by mostresearchers were summarized. While the application fields and development prospect of digitalwatermarking technique were introduced and discussed, this laid a good foundation for in-depth researching on the specific algorithm of digital watermarking.Second, the digital watermarking technique of hiding data (the embedded information can be anyforms) in an image was introduced simply, which was called image watermarking technique.According to the robustness, this paper mainly introduced common image watermarking whoserobustness and fragileness were both not emphasized, robust image watermarking and fragileimage watermarking, and analyzed the classic algorithms. Then, basic theories and applicationsof wavelet transform were given, and the encoding and decoding system, main characteristicsand the wavelet transform of the second Joint Photographic Experts Group 2000 standard weregiven. Combined with the multi-resolution analysis of wavelet transform, a digital watermarkingscheme based on DWT which resist JPEG2000 attack was proposed, and the watermarkinginformation was a binary image in this scheme. Two-level discrete wavelet transform wasperformed to the original image, then the detail subband high frequency coefficients: LH2, HL2and HH2 were selected, and then embedded the watermarking information into them using theDither Modulation (DM) algorithm, that the invisible and better robustness of the watermarkingscheme could be consistent implementation. Then, simulation and experimental analysis byMATLAB were taken, the proposed scheme could maintain a good image quality, also had agood performance to resist JPEG2000 compression and other common cutting, noises andwhirling attacks.After the fast development in last decade, digital watermarking technique has make manybreakthroughs and had lots search results, as one of the key technique for copyright protection.Meanwhile, many research scholars in other fields has been put their focus into the digitalwatermarking fields, and numerous academic conferences of different scales were held all overthe world. However, behind the optimistic future, there are still some different problems to bework out and some key projects to be broken in the prospect of digital watermarking technique.So far the mathematical model of digital watermarking which can integrate the researchbasement is not yet established. And there are few breakthrough results in capacity analysis,evaluation indexes and policies and regulations of digital watermarking technique. In the end, thepaper made a conclusion and gave the outlook of the digital watermarking techniquedevelopment.