基于小波变换的局部化数字水印算法

Localied Digital Watermarking Algorithm Based on Wavelet Transform

为了解决许多水印算法不能抵抗任意剪裁的缺点,提出了局部化数字水印算法.通过二维Mexican Hat小波变换提取图像中的多个特征点,在以特征点为中心的局部化区域中分别进行小波变换,并通过对小波系数进行单系数量化来实现水印信息的嵌入,同时水印的提取不需要原始图像的参与.实验结果表明,在剪裁后待检测图像中至少包含一个嵌入水印区域的前提下,该算法对JPEG、JPEG2000压缩和任意剪裁具有很强的抵抗能力.

In order to resist the attack caused by artrarily cropping the watermarked image, A localied digital watermarking algorithm was put forward. A few feature points are retrived by Mexican-Hat wavelet transform. The watermarks are seperrately inserted into the wavelet domain of local regions, whose centers are the stable feature points of the image, by quantifying the single DWT coefficient. The watermatks can be detected without knowing the original image. Experiments show that the local digital watermarking proposed in this paper is very robust to JPEG,JPEG2000 compressing and arbitrarily cropping,on condition that the cropped image must contain an embedded waternarks region at least.