一种基于仿射矩阵校正的抗几何攻击水印算法

A watermarking algorithm against geometric attack based on affine matrix correction

随着水印技术的发展,大多数字水印算法都能有效抵抗一般攻击,但如何在保持较大水印嵌入量的同时,又能有效抵抗几何攻击和组合几何攻击是当前研究的一个难题.因而,提出了一种有效抵抗几何攻击与组合攻击的数字水印方法.首先,水印被嵌入图像具有较强鲁棒性的QR域中的R矩阵中;然后,提取受攻击图像小波域上的特征参数,并利用最小二乘支持向量机(Least Squares Support Vector Machine,LSSVM)对图像攻击参数初步识别;最后,通过模板水印对攻击参数的精细识别,进而实现对受攻击图像的几何校正与水印的提取.同时,为了降低水印的误码率,引入BCH编码技术.经过理论分析与实验表明,该方法对一般的几何攻击和组合攻击具有较好的鲁棒性,且水印的嵌入容量大.

With the development of watermarking technology,most of the watermarking methods can effectively resist the general attacks,but there is still great difficulty for geometric attacks and combined geometric attacks while maintaining a high embedding capacity.Therefore this paper proposes a method which effectively resists geometric attacks and combined attacks.Firstly,the watermark is embedded into the R matrix the QR domain of image with strong robustness.Secondly,the feature parameters of the attacked image are extracted in the wavelet domain and attack parameters of image are preliminarily estimated using LSSVM,then attack parameters are estimated accurately by template watermarking.Lastly,the image is corrected geometrically and watermark is extracted.Meanwhile,in order to reduce the bit error rate of watermark,we also introduce BCH encoding technology.The theoretical analyses and experiments show that the proposed method has good robustness to the general geometrical attacks and combined attacks,and the embedding capacity of watermark is high.