The Design Of Image Digital Watermarking Based On The Human Vision System

Digital image watermark, as a branch of data hiding technology, imbeds symbol information into the protected image using the redundancy attribute of Human Visual System. As an effective approach of copyright protection of digital image, it has become a hotspot in the field of information security recently.In this article, it describes the background, the status and the theories of the digital watermark technology at first. Then it describes the human visual system (HVS) and the application of HVS in digital watermark technology, and enumerate some watermark algorithm based on HVS. The article is about the copyright of digital image, and it studies a new watermark algorithm for color images based on HVS and discrete wavelet transform(DWT). Watermark embedding of this algorithm is processed in YIQ color space. Watermark is meaningful binary watermarking image. Before embedding watermark, three random permutations are taken to enhance security and noise immunity. In the process of embedding, wavelet coefficients of Y-component are signified based on the masking properties of HVS. They are quantized by calculating JND threshold. Then three permuted watermark series are embedded in different intensities into wavelet coefficients of different directions. The extraction of watermark don't need original image. Watermark series are extracted after the quantized procession of wavelet coefficients. Finally, watermark image is get by restoring the scrambling of watermark series. The algorithm of this thesis is experimented in Matlab. The results shows that it behaves well in concealment, and it is robust enough to resist some familiar image degradation processingA digital watermarking system based on the copyright of digital images is designed and realized. A number of experiments and analyses prove that the algorithm of this system behave well in concealment and robustness. It will be useful in application.