The Study Of The Watermarking Algorithm Based On Independent Component Analysis And Spread Spectrum

With the rapid development of computer and network technology, the information of digital multimedia becomes more easily to acquire. While at the same time, it also becomes more easily to suffer the illegal copying, fabricating, tampering, infringement etc. attacks. The conventional safety precautions which based on the cryptology have the ability not equal to their ambition. In order to protect the digital product itself security as well as the owner's benefits, people put forward the digital watermarking techmque. Digital watermarking is a kind of technology which is to protect the digital products by embedding invisible secret information without affecting the using quality of the digital products. Generally, it demands three basic characters of imperceptibility, robustness and security.In the beginning, the background and the actuality of digital watermarking is introduced, dissertate the digital watermarking about the basic concept and character, generic model, typical algorithms, attack analysis and evaluation of performance. Then the theory and application of independent component analysis, the spread spectrum technology and the human vision system are introduced.Based on the analysis of the research in existence of the digital watermarking algorithm, we put forward an adaptively robustness digital watermarking algorithm which based on ICA and SS. The paper mainly carried on three aspects work of the followings:(1) Put forward using the two-value image which has meaning as watermark information, and pretreatment the watermark with spread spectrum technology before it being embedded. In this way the watermark's robustness was strengthened.(2) According to the characters of wavelet transform, combine the HVS(human vision system) models, adopt multiresolution analysis technology and carry on embedding in low frequency coefficients after the original image was disassembled with wavelet, thus the algorithm's imperceptibility and robustness request was contented better. (3) For strengthening the security of the watermark algorithm, the paper put forward to the thought of the watermark being embedded by a rand combining matrix. The extraction of the watermark signal is by the FASTICA algorithm.Plentiful emulate experiments prove that the algorithm assures the watermark's imperceptibility and robustness to familiar image process such as zoom, circumrotate, compression, cropping, noise contamination, etc.