Digital Watermarking Algorithm Based On Transform Domain

As the rapid development of the Internet, communication and multimedia technology, multimedia digital product copy and distribute becomes very easily, so the problem of multimedia information security caused people more and more attention. Digital watermarking technology can effectively solve the problem, now has become a hot spot of research in the field of information security. In the base of the analysis and study of domestic and foreign digital watermarking technology results, this paper focuses on the transform domain digital image watermarking technology, the main research works are as follows:In the first,I introduced the basic concepts,the research significance, the research present situation and application fields of the digital image watermarking. Then the readers have basic understanding of the digital watermark.2. At first, I introduced some concept, classification and characteristics of the digital watermarking .Then some of the related to digital watermarking technique were reviewed in this chapter, those technology including some quantization embedding formula.3. According to the human visual system characteristic and the masking of discrete wavelet transform characteristic, this paper puts forward a kind of color image watermarking algorithm based on HVS and DWT. At first,this watermarking algorithm uses chebyshev maps to the original binary watermarking for encryption. And then the Y compent of the discrete wavelet transform of the host images is abstracted. Through the visual masking properties of the human visual system of the low frequency sub-band cover LL1 value, adjust the from of the watermark embedding strength, so as to realize adaptive watermark.4. This chapter puts forward a kind of Contourlet domain color image blind watermarking scheme. The algorithm use a chaotic encryption algorithm to encrypt watermark; And the watermark is embedded in the low frequency sub-band weight coefficient domain of Contourlet transform of the color image. The experimental results show that this algorithm can satisfy the invisibility, also has strong robustness for added noise, shear and JPEG compress.5. At last,this chapter introduces a watermarking algorithm for color image based discrete wavelet transform. Firstly, I use the discrete wavelet transform to the host image , and the watermark is embedded in the wavelet coefficients. Then use the inverse discrete wavelet transform to get the watermarked image. In the process of watermarking extraction, this paper using a blind extraction method to extract the watermark.