基于改进的不变质心和小波域的鲁棒数字图像水印方法

Robust Image Watermarking Based on Improved Invariant Centroid and Wavelet Domain

利用图像不变质心在图像中的相对位置对平移、旋转和缩放的不变性,提出了一种抗几何攻击的图像盲水印算法。算法首先根据水印比特的长度自适应地对原始图像进行特定级的小波分解,并修改某些相对稳定的最低一级的低频子图的小波系数,通过将修改后的系数进行小波重构来嵌入水印。接下来以含水印图像的基于改进的不变质心的不变特征矩阵为基础,与Rijndael加密技术相结合,生成相关的二值逻辑表作为密钥向第三方认证,达到版权保护的目的。该算法在提取水印时不需要原始载体图像和原始水印。实验结果表明,该算法时间复杂度低,能有效抵抗JPEG压缩、裁剪、噪声等常规攻击以及平移、旋转、缩放等几何攻击。

A geometrically robust blind watermarking algorithm was proposed using translation,rotation and scaling invariant property of relative coordinate of the invariant centroid.With certain level wavelet decomposition according to the length of the watermark bits,after modifying some selected coefficients in the lowest frequency of the last level for its robustness to the interference,the modified coefficients were applied to obtain the watermarked image by wavelet reconstruction.With the improved invariant centroid based characteristic matrix and the Rijndael encryption,a related binary logical table was produced.As the secret key,the table was used to apply to the third party for copyright protection.This arithmetic can extract the watermarking without the original carrier image and the original watermarking.Experimental results show its low time complexity and robustness to the common attacks such as JPEG compression,cropping and added noise,as well as the geometric attacks such as translation,rotation and scaling.