基于混沌和SVD-DWT的数字图像水印算法

提出了一种基于奇异值分解和离散小波变换相结合的数字水印算法。将二值水印图像用混沌的方法进行置乱并对原始图像进行N层小波分解,对小波系数LLn,LHn,HLn,HHn分别采用不同的方式嵌入水印信息。对LLn部分,根据系数的能量大小嵌入伪随机扩频序列;对LHn,HLn,HHn三个小波系数矩阵作奇异值分解,将置乱水印的奇异特征值嵌入到这三个小波矩阵的奇异特征值中。针对嵌入方案,设计了非盲检测和盲检测算法。实验仿真表明,该算法能够经受住噪声、中值滤波、JPEG压缩和剪切等攻击,具有较强的鲁棒性。

Digital Image Watermarking Algorithm Based on Chaos and SVD-DWT

In this paper,a digital watermarking algorithm based on singular value decomposition(SVD) and discrete wavelet transform(DWT) is proposed.The watermarking image was scrambled by chaotic and the original image was decomposed with DWT.The wavelet coefficients matrixes LLn,LHn,HLn,HHn were imbedded into watermark by different methods.LLn was imbedded by pseudo-random after spreading according to the energy.Decomposing the three wavelet matrix coefficients LHn,HLn,HHn with SVD,the SVD of the scrambled watermarking was imbedded to the SVD of the wavelet coefficients.Based on the imbedding scheme,retrieving detection algorithm and blind detection algorithm are designed.Experiment results showed that the proposed watermarking algorithm was robust to noise,median filter,JPEG compression,and cut etc.