Research On Digital Watermarking Algorithm Based On Chaos

With the rapid development of computer network technology and multimedia technology, multimedia data is becoming the main source from which people get information from, and multimedia data is becoming an important component of people's life. To protect the copyright of the digital product owner is becoming more and more important as an important factor of keep the development of digital media industry in good shape, but the traditional information security technology and encryption theory can't solve the problem of digital product copyright protection, watermarking technology rises up in this case. Watermarking technology, as an important method of protecting copyright, are under abroad research and application at present. Watermark can prove the ownership or integrality through embedding secret data-watermark in the original data, thus it can protects the digital product from pirate and tamper.In the paper, the technology and application of the digital image watermarking are deeply analyzed and studied, the main work is as follows:(1)We make a recapitulative summarize and analysis for the basic knowledge of digital watermarking technology from its origin, basic character, sort, common model, main application field and so on.(2)The character of the chaotic system is summed up. This paper summarises the development history of chaos, and it is an emphases of discussing about the Lyapunov exponent and the chaos attractor.(3)In this paper an improved algorithm in DCT domain based on chaotic sequence is proposed. Exploiting some characteristics of Human Visual System (HVS), watermark is adaptive embedded into the DC components of the original image. The experimental results show that the watermarks are invisible and robust against noise and commonly used image processing methods such as Gaussian, JPEG, Median filtering etc.(4)A new digital image watermarking algorithm is proposed in this paper based on discrete wavelet transform and chaotic shuffle. In this algorithm, in order to enhance the watermarking encryption and vision effect of the extracted watermarking, firstly a two-value watermarking signal should be dealt with by shuffle. At the same time, DWT has favorable frequency character and the multiplayer decompose analyses is identical with human's vision custom, such is special useful for selecting embedding position and intension in Digital Watermarking. Simulation results show that such scheme is good at transparence and robust against cropping, filter, noise disturbance and so on. Especially for JPEG compression, clear mark can be still extracted from the compressed watermarked image even there is great degradation in watermarked image.