基于分块的小波域图像半脆弱水印认证算法

A Semi-fragile Watermarking Authentication Algorithm Based on Block and Wavelet Domain of Image

提出一种图像半脆弱水印认证算法,该算法将图像分成四块,从三级小波分解的低频系数中提取每部分图像的特征作为水印,嵌入到载体图像的各分块中,水印提取既不需要原始图像,也不需要原始水印信息.理论分析及实验结果表明,该算法可以对任意大小的载体图像进行水印嵌入,具有很好的透明性,不仅能抵御噪声、有损压缩等非恶意攻击,还能有效地检测定位剪切、替换等恶意攻击.

A new semi-fragile watermarking authentication algorithm is proposed,the algorithm first divides the image into four blocks,then the feature of each block of image is extracted from low frequency coefficient of three level wavelet transform,and then the feature as the watermark is embedded into corresponding block of image,the four blocks embedded into watermark were combined into a new image.The watermark can be extracted without involving either the host image or the original watermark.Theoretical analysis and experimental results show that the algorithm can be carriers of images of any size,and with good transparency,and it can not only resist non-malicious attacks,such as noise and lossy compression,it can also effectively detect and locate the cut,replaced,and other malicious attacks.