基于图像特征的数字水印算法研究

为了使数字水印具有更鲁棒的抗攻击能力，提出了一种基于图像特征的数字水印新算法。该算法首先利用Harris—Laplace算子提取载体图像特征点；然后结合特征尺度白适应确定局部特征区域；最后，采纳DFT中频幅值比较策略将数字水印信息重复嵌入到多个不相交的局部特征区域中。检测时，根据模糊模式识别的最大隶属度原则检测水印信息。仿真实验结果表明，该新算法不仅具有较好的透明性，而且对常规信号处理（中值滤波、边缘锐化、叠加噪声和JPEG压缩等）和去同步攻击（旋转、平移、缩放、行列去除、剪切和局部随机弯曲等）均具有较好的鲁棒性。

A New Featured-based Image Watermarking Algorithm

In this paper, a novel feature-based image watermarking scheme is proposed. Firstly, the Harris-Laplace detector is utilized to extracted feature points, which can survive a variety of attacks. Then, nonoverlapped disks around local feature points are defined adaptively according to the feature scales, Finally, several copies of the digital watermark are embedded into the nonoverlapped disks by comparing the DFT mid-frequency magnitudes. In watermark detection, the digital watermark can be extracted by using the maximum membership criterion. Experimental results show that the proposed scheme is not only invisible and robust against common signals processing such as median filtering, sharpening, noise adding, and JPEG compression, but also robust against the desynchronization attacks such as rotation, translation, scaling, row or column removal, shearing, and local random bend.