基于Tchebichef不变矩的多比特抗几何攻击图像盲水印算法

现有的大多数水印算法对旋转、平移和尺度变换等几何攻击的鲁棒性比较差,微小的几何攻击都有能导致水印检测器失效,因此水印算法对几何攻击具有鲁棒性非常重要。本文提出了一种基于Tchebichef不变矩实现的多比特几何攻击不变性图像盲水印算法。文中具体介绍了Tchebichef不变矩的构造方法,水印是事先产生的与原始图像无关的信号,嵌入过程中将水印嵌入到图像的Tchebichef不变矩中实现几何攻击不变性。水印检测过程中采用独立分量分析技术实现真正意义上的多比特水印盲检测。文中具体分析了所提出的水印算法的计算复杂度,实验过程中采用通用水印测试软件Stirmark对所提出的水印算法进行鲁棒性测试,实验数据说明这种水印算法对Stirmark具有很好的鲁棒性。

Geometric Invariant Multi-Bit Blind Image Watermarking by Invariant Tchebichef Moments

Many proposed image watermarking techniques are sensitive to geometric distortions,such as rotation,scaling and translation.Geometric distortions,even by slight amount,can make the decoder disabled.Therefore surviving geometric attacks in image watermarking is considered to be of great importance.In this paper,a geometric invariant multi-bit blind image watermarking is designed and test against attacks performed by Stirmark using the invariant Tchebichef moments.The detailed construction of invariant Tchebichef moments is expressed.Watermark is produced independent to the original image and is inserted into the perceptually significant invariant Tchebichef moments of original image.The watermark decoder extracts the multi-bit watermark blindly,which adopts Independent Com- ponent Analysis(ICA).The computational aspects of the proposed watermarking are also discussed in detail.Experimental results have demonstrated that the proposed watermarking technique is robust against geometric distortions such as rotation,translation and scaling.It also has a good robustness against other attacks performed by watermark test software-Stirmark,such as cropping,faltering,image com- pression,random geometric distortions.It is indicated that the proposed watermarking has superior advantages over the existing ones in many aspects.