基于几何矩的抵抗RST攻击的数字图像水印

Moment Based Multibit Digital Image Watermarking Resisting to RST Attacks

目前大多数的数字图像水印方案不能有效抵抗几何形变的攻击,这一弱点已成为数字水印技术走上商用的瓶颈。在各种几何形变中,RST(旋转、缩放、平移)是最为常见的攻击方式。该文提出了一种具有普适性的能够抵抗RST攻击的多比特数字图像水印方案,采用的主要措施有:(1)提出一种基于几何矩的图像标准化方案以抵抗几何攻击;(2)采用扩谱方法构造二维CDMA水印信号,实现多比特水印嵌入;(3)根据HVS特性自适应调整水印的嵌入强度,在鲁棒性和不可见性之间达到平衡;(4)利用MAP和相关方法估计和检测水印信号。实验表明该方案对RST具有很高的鲁棒性,对压缩、滤波等常见的图像处理攻击同样具有良好的鲁棒性。

At present, most image watermarking schemes can not effectively resist geometrical attacks, which restricts the applications of digital watermarking techniques. RST （Rotation, Scaling, Translation） are frequently used geometrical attacks. In this paper a general multi-bit watermarking scheme for digital image that can resist to RST attacks is proposed. The measures taken in the scheme include： （1）a moment-based image normalization method is proposed to resist RST; （2） The multi-bit message is hidden in a 2D CDMA watermark using spread spectrum technique; （3） The watermark is embedded into cover image exploiting the properties of HVS to obtain the compromise between watermark robustness and invisibility. （4） The watermark is estimated according to MAP and detected by means of correlation-detection. Experimental results show the scheme is robust to compression, filtering as well as RST attacks.