一种可抗几何攻击的图像鲁棒水印算法  

Robust Image Watermarking Scheme Against Geometric Attacks

作　　者：赵艳丽[1] 王兴[2] 马晓普[1] 李争艳[1] 

机构地区：[1]南阳师范学院计算机与信息技术学院,河南南阳473061 [2]南阳师范学院软件学院,河南南阳473061

出　　处：《小型微型计算机系统》2014年第8期1931-1936,共6页Journal of Chinese Computer Systems

基　　金：国家自然科学基金委员会-河南省人民政府人才培养联合基金项目(U1304619)资助;河南省重点攻关项目(082102210067;112102210408)资助;河南省基础与前沿技术研究计划项目(122300410426)资助.

摘　　要：抗几何攻击是鲁棒水印算法研究的关键问题之一,基于归一化的技术虽然具有一定的抗几何攻击能力,但对于剪切等图像内容丢失攻击显得无能为力.针对该问题,结合图像特征点及梯度方向,提出一种可抗几何攻击的鲁棒水印算法.由于在图像几何变换中,图像两个点处的梯度方向夹角能够保持不变,因此算法通过修改两个特征点间的梯度方向夹角进行水印嵌入,并在理论上给出了可通过修改特征点处邻域的DCT系数以完成上述嵌入过程.该算法不需对图像或图像的区域进行归一化处理,从而避免了因图像内容丢失而引起的归一化不同步问题.实验结果表明,算法能够抵抗多种对含水印图像的常规处理攻击和几何攻击,尤其对于裁剪攻击具有较好的鲁棒性.Against geometric attacks is one of the key issues for robust watermarking. Though the method based on normalization tech- nique has capability to resist geometric attack, it shows powerless for shearing and cropping attacks. For solving the problem, combi- ning with the feature point and gradient orientation, a robust watermarking scheme against geometric attacks is proposed. Due to the angle between the gradient orientations of two different feature points can be maintained under geometric attacks, the watermark can be embedded by modifying it. And the method which can modify the DCT coefficients of neighborhood of the feature point is given in theory in order to complete the embedding process. The algorithm does not need normalization process of the whole image or a region of the image. So it can avoid the out-synchronization problems of normalization caused by the shearing and cropping attacks. Experi- mental results show that the algorithm can resist many of image processing attacks and geometric attacks, especially for shearing and cropping attacks.

关 键 词：数字水印 鲁棒性 特征点梯度方向 几何攻击 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]