Dual Color Image Watermarking Algorithm Based On Wavelet Transform

With the computer communications technology and the rapid development of internet, the protection of the multimedia,such as image,audio,video etc, becomes a problem needing solved urgently. The digital watermarking as an important copyright protection ways, has been developed rapidly in recent years. At present, on the network are mostly color images, these color images copyright protection is also an urgent need to solve. Therefore, researches in this paper mainly focus on the watermarking technologies for color images, the main research work are listed as follows:This paper summarizes the research background, applications of digital watermark and the state of the art, introduce the classification of digital watermark,classical algorithm,basic feature,common attack methods and evaluation standard. And also introduce the basic theory of wavelet analysis, wavelet decomposition and two-dimensional image reconstruction, as well as the wavelet theory in the application of digital watermarking. In order to enhance the security of digital watermarking system, here it propose an image Scrambling algorithm based on the magic square and ranks transform in the paper,because it has the absolute advantages comparing with other algorithms due to its less calculation time and better result.This paper designs an improved color image watermarking algorithm, in accordance with the visual characteristics of the Human visual system, we can see that the human eye on the green color component is most sensitive to changes in weight, less changes of the blue, but embed information into the red color component can increase robustness. Therefore this paper in red and green component embedding few information, in blue color component embedding lots of information, this paper uses a different color by multiplying the weighting coefficients of different ways to solve the visual distortion, and by embedding watermark into the middle frequency and many low frequency method of wavelet coefficients to enhance the watermark robustness. Experimental results show that the proposed algorithm keeps the quality of the image well and is robust enough to noise,filtering,sharpen,image scaling etc.