Still Images Robust Watermark Algorithm And Performance Evaluation Method

With the rapid development of computer network technology,the storage,copy and transmission of digital multimedia is becoming very convenient.How to implement effective protecting the copyright of multimedia in the network environment is becoming a hot issue in in international academe,business circles and government departments concerned.This article has made the quite comprehensive introduction on the basis of the elementary theory about the digital watermark technology.From the watermark robustness, transparency,security and watermarking capacity and may be subject to attack several aspects,Watermarking performance Evaluation system has been prented.In introduces the Wavelet and the Contourlet transformation knowledge foundation, emphatically carries on the statistical analysis to the Wavelet transformation and the Contourlet transformation high frequency coefficient.Had proven from the theory and the experimental aspect the Wavelet transformation and the Contourlet transformation high frequency coefficient conforms to the generalized Gaussian distribution.Differing from wavelet transform,Contourlet transform has the ability of image multi-scale and direction decomposition using the anisotropic basis,thus it is better to capture the curve singularity and much more match the HVS properties.A unified robust and perceptual watermarking algorithm is presented with respect to two transform domain.The watermarks are adaptively embedded in each frequency sub-band,with the strength adjusted by the visual saliency of transform coefficients.Some experiments of such algorithm in two multi-resolution decomposition frameworks are given with respect to several common attacks.Experiment results show that the contourlet based algorithm has better safety, robustness and invisible compared with wavelet based algorithm.Using the estimation of marginal and joint statistical distribution of Contourlet coefficients via the method of maximum likelihood estimator,multiplicative watermarking and blind detection framework is presented in the Wavelet transformation domain and the Contourlet transformation domain.Experiments prove that Wavelet transform domain and Contourlet transform domain by Watermark detector with a good detection performance...