Based On Human Visual Characteristic And Wavelet Transform Domain Digital Watermarking Algorithm

With the development of digital multimedia technology, digial watermarking has become a popular topic in the field of digital copyright protection. Digital watermark protects the securities of digital multimedia by embedding special information into it. Applications of watermarking include not only copyright protection, but also document authentication, covert communications, data embedding and so on. In these applications, a watermark is embedded into a host data. This embedding should be nearly imperceptible and robustness against possible manipulations of the watermarked data, in the sense that it should be possible to reliably extract the watermark from a degraded version of the signal. Degradations include operations such as addition of noise, filtering, compression and geometrics distortion. These degradations could be intentional or nonintentional. The designing of a watermark resistant to these distortions is still an open problem. Robustness is crucial for watermarking technology in order to be used widely in commercial areas.Digital watermarking has been proposed as a way to claim protection. In this paper, we try to use the error-correcting code skill, the multiresolution of wavelet transformation, and the human visual system to improve the traditional watermarking. Error-correcting based watermarking will have the property that corrects errors of the extracted watermark automatically. The HVS (Human Visual System) model will be presented to investigate perceptually characteristic parts of human (e.g. intensity or hue) and how to insert the watermark into the original data, where the perceptual sensitivity of human is relatively low. A multiresolution watermarking based on the wavelet transformation is selected in each frequency band of the Discrete Wavelet Transform (DWT) domain and therefore it can resist the destruction of image processing. In our experiments, the results show that the robustness of a watermark with ECC (Error Correct Coding) is much better than the traditional one without ECC.For enhance the watermark robustness and application, in the paper ,a new embedding strategy for the watermark is proposed based on DWT domain. The algorithm is proposed based on the influence of the selection for wavelet bases and the robustness of watermarking. We select wavelet Haar base, according to watermark's length and human visual characteristic, with wavelet transform, the image is decomposed into suitable classification, Watermark components with different strength are inserted into different wavelet coefficients based on the results of classification. Experimental results show that the proposed algorithm is robust to some image processing operations and Joint Photographic Experts Group(JPEG).