Robust Digital Watermarking Algorithms Based On Multiple Transform Domains

The emergence of digital watermarking technology provides an effective method for multimedia copyright protection,which embeds specific information,i.e.,watermark,with the signal processing approaches into the original information.In this dissertation,two kinds of digital watermarking algorithms based on multi-transform domain are designed.Simulation experiments and analyses,the imperceptible and the robustness of the two watermark multi-transform-domain algorithms verify.The main research contents of this proposed dissertation are as follows.A digital watermarking algorithm based on discrete wavelet transform,discrete cosine transform and discrete fractional random transform is proposed.First the watermark is scrambled by the Arnold transform,then the row and the column of the resulting watermark are scrambled by the Logistic map,respectively.In addition,four sub-band images are generated from the host image by the two-dimensional discrete wavelet transform.The low-frequency sub-band image is divided into 8×8 small matrices,and a coefficient matrix is produced by performing the discrete cosine transform on each matrix.An intermediate matrix with the same size as the watermark image is constructed by the intermediate frequency coefficients.Then the discrete fractional random transformation is performed on the intermediate frequency coefficient matrix and the scrambled watermark is embedded into the discrete fractional random transformation domain.Simulation results show that the proposed digital watermarking algorithm is imperceptible and robust.A digital watermarking algorithm is designed based on 4-level discrete wavelet transform,discrete cosine transform and singular value decomposition.The 4-level diagonal sub-band images are obtained by performing 4-level two-dimensional wavelet transform on the original image,and then the coefficient matrix is produced applying the discrete cosine transform on the 4-level diagonal sub-band images.Then,the diagonal matrix is obtained by performing the singular value decomposition on the coefficient matrix.In addition,the watermark is scrambled by the Arnold transform and the Logistic map.And the singular value decomposition is executed on the scrambled watermark,and the watermark is embedded into the singular value of the scrambled watermark and the singular value of the coefficient matrix.Simulation results demonstrates that the digital watermarking algorithm can resist common digital signal processing attacks,such as JPEG compression attack,salt and pepper noise attack,Gaussian noise attack,filter attack,brightness change attack,geometric attacks,cut attack,and etc.