为了更好地保护数字产品的版权,本文提出了一种提升小波变换与奇异值分解相结合的彩色图像数字水印算法.提升小波变换运算速度快,能够对任意尺寸图像进行变换；奇异值分解具有几何不变性,并且体现图像的内蕴特性.算法充分利用提升小波变换和奇异值分解的优良特性,选择彩色图像的蓝色通道进行水印嵌入.首先对原始图像进行多级提升小波变换,然后选取中低频子带进行奇异值分解,将灰度水印图像进行Arnold置乱后分成四个部分嵌入所选子带的部分奇异值矩阵中.在水印提取时不需要原始载体图像,更加有利于实际中的应用.实验表明,该算法具有良好的透明性,而且对大部分常见攻击及几何攻击有很好的鲁棒性.%In order to protect the copyrights of digital products, a color watermarking algorithm based on lifting wavelet transform (LWT) and singular value decomposition(SVD) is proposed. The LWT is quick and it is suitable for any size of image. The SVD has geometrical invariances and it shows the intrinsic characteristics of the image. This algorithm makes use of the characteristics of the LWT and the SVD, and chooses the blue channel of the color image to embed watermarking. The algorithm firstly uses multi-levels LWT on the original image, secondly applies the SVD on low frequency subband and middle frequency subbands, thirdly uses Arnold to scramble the gray-scale watermarking, and finally divides it into four parts that are embedded into the singular values matrices . It does not need the original image when the watermarking is extracted, so it can be better applied into the practice. The experiment shows that the algorithm has good transparency and robustness to common attacks and geometric attacks.
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