Research On Adaptive Watermarking Algorithm For MPEG-4

Digital watermarking is an important branch of information hiding and a new digital products protection technology. It is a process of embedding a watermarking, such as author's copyright information or authentication information, into various digital products, such as images, audio, video or software etc. By this way, watermarking can distinguish the illegal copy and embezzlement of the digital products and protect intellectual property right. As MPEG-4 video standard is more and more used for applications such as video editing, network video communications, the MPEG-4 video data must have a copyright protection such as watermarking to protect the copyright.This paper fisrtly points out the important meaning of digital watermarking to the science research and industry production based on the background of problem studied, and analyzes the current status and developing trend of the digital watermarking. And then the basic principles, features and problems of watermarking and MPEG-4 are summarized. The image and video watermarking are researched thoroughly.Three algorithms are put forward in this thesis for image and MPEG-4 video: 1. A new discrete consine transformation (DCT) watermarking algorithm is proposed based on Watson model. The embedded position is fixed on by Watson model. In order to encrypt the watermarking, the spread-spectrum is introduced. This scheme has strong robustness. 2. A new watermarking algorithm based on discrete wavelet transformation (DWT) is proposed. Through analyzing the character of DWT, the intensity and position of embedded are confirmed. The experimental results demonstrate that the arithmetic has the ability of defending tamper and accurately locating where watermarked image has been tampered. 3. This dissertation proposes a new adaptive watermarking algorithm based on I frame of MPEG-4. I frame is selected as the watermarking embedded frame. It combines DWT's character with DCT's character and selects eight DCT middle frequencies as the embedded frequency. The watermarking is embedded adaptively by veins character. This algorithm is easy to be used in MPEG-4 video. The test results indicate that it has well unvisible and strong robustness on compressed and nosing.The MPEG-4 digital watermarking mentioned here is only for uncompressed. But those for compressed are not concerned in this thesis.