An Adaptive Watermarking Algorithm For Image Based On Wavelet Transform

Digital watermarking technique is a new research direction in information security field now. This paper researches the digital watermarking technique. At first, we introduce the basic character, theory, research status of digital watermarking and watermarking system frame. We present the common digital watermarking algorithm, wavelet transform theory and the watermarking system theory based on the wavelet decompose in detail, and realize a watermarking algorithm by embeded in the middle frequency of wavelet domain.Secondly, we discuss the difference of watermarking embedding formula and several different methods of choosing embedding coefficient, and find the optimum style of choosing coefficient. In this paper, we give the embedding watermarking algorithm in middle and low frequency in wavelet domain.Thirdly, we introduce the common image shuffling technique and present a new changing pixel location approach based on magic square.At last, we give a new adaptive watermarking algorithm based on wavelet transform in the foundation of shuffling arithmetic in last chapter. By the character of human visual system and the different cover peculiarity, we classify the wavelet sub-block and combine the nature of wavelet transform, then embed the different intension watermarking into different wavelet sub-blocks.This paper give the experiment data of all algorithm presented and analyses them. The results show that all the algorihm presented in paper have strong robustness and good invisibility.