Study Of The Chatic Watermark Algorithm Based On Wavelet

Nowadays, today in the development of digital,information technology rapid development, people give more attention to information security. The discipline of information hiding has become the focus of infaomation security. Because each Web site and network communication depend on the multimedias (such as audio,video and image and so on), so the problem of security information is worth studying. And the information hiding that let the secret information into the carrier,ensuring that has the smallest difference with the original carrier. So in the absence of relevant information and special testing tools, the attackers are imperceptibly have the existence of hidden information. So in this case,the digital watermark technology was born.This paper what to produce random sequence use the Logistic chaotic and than to make the watermark;later,using the wavelet analysis method to embed the watermark into the carrier;finally,using the attack detection model to check watermark image. In this paper, the most important content has three point s.The first paragraph,the produce of chaotic watermark. Firstly,getting the random numbers by Logistic chaotic. Secondly,the chaos random sequence is converted into binary matrix through a centain decision rules. Thirdly, getting a basic watermark template by using the cellular automata, and get the final template throuth the chaotic watermark by smoothing processing. The second paragraph, watermark embedding. Firstly,according to the demand for the carrier by multi-level discrete wavelet transform,and getting the different scale coefficients of the low and high frequency. Secondly,according to the degree of visual impact,and selecting the best part for the embedded secret information. Thirdly,it’s time for the embed secret information of wavelet domain image to correspond wavelet inverse transform. It can complete the hidden process.The third paragraph,watermark detecting.Firstly,it separately correspond level discrete wavelet transform for the carrier image and hidden image.Secondly,it compare the corresponding subgraphs that is respectively to get and find the hidden information subgragh.Thirdly,it is to go ahead wavelet inverse transform for the subgragh that get and restore the hidden information. Of course.If the secret information is the image,it should be on the level of the wavelet reconstruction.The paper designs the simulation experiments. The invisibility and robustness reach a good balance about this watermark system.Through the simulation experment results can be seen,the watermaerk system has a certain amount of resistance for the general, rotation, compression,shear,add noise and filtering,and so on.The watermark system also has a certain resistance for the fuzzy attack and the Mosaic attack.