Based On The Study Of Wavelet Transform Techniques And Digital Image Watermarking Techniques

The rapid growth of the information technology, the development of economy, the increasingly easy access to digital media, and the increasingly powerful digital media manipulation tools has made media security a very important issue. The digital watermarking is the new measure of digital media protection, which is a process of embedding hidden messages within digital media such as text, images, video and audio. The hidden messages could be copyright information, user distributor identification number, company logo, personal signature, control bits, or any information considered useful for a specific application. Image digital watermarking can provide effective protection for image authentication, forgery, falsification, security and intactness by embedding a special invisible mark into multimedia data, such as audio, video and images, etc. Frequency domain watermarking schemes can be taken advantage of the characteristics of Human Visual System and can be compatible with the International Compression Standard, and its energy can be distributed over all pixels of image in the spatial domain.This dissertation emphasizes on following issues:First, the background and current research situation of the issue are reviewed. The emphasis of discussion is put on the related techniques of digital watermarking. The category of image watermarking system is summarized. The difference among spatial domain watermarking and watermarking is based on fractals which are analyzed.Second, based on the wavelet analysis theory, a deep discussion on application of the wavelet transform to the digital watermarking technology is given.Third, from three aspect of chosen of watermark information, the choice of watermark transform domain and transform method, and watermark hiding and detecting algorithm, the digital watermark technology is studied in detail. One visually recognizable watermark is embedding and extracting system for binary images are designed and realized.Finally, the influence of different attacks, the various resolution levels, the intensity of watermarking and the different wavelet functions on digital image watermarking are researched.The experimental results have shown the researched method is feasible and effective. The algorithm is simple and easy to realize: The embedded watermarking is not only adaptive to the original image but also highly robust and the extracted watermarking information is easy to distinguish.