基于四叉树的小波域图像零水印算法

图像零水印技术打破了常规水印算法修改图像数据以嵌入水印的作法，通过图像的特征构造具有标识意义的水印信息来实现图像的版权保护．针对现有零水印算法计算量大以及鲁棒性不佳的缺陷，提出一种新的小波域零水印算法．该算法结合图像的四叉树分解原理，利用图像小波域低频系数的特征来构造零水印．实验表明，该算法对图像的识别性能强，且具有良好的抗攻击能力，是一种有实用意义的零水印构造法．

A Quadtree Based Image Non- Watermark Algorithm by Discrete Wavelet Transform

To protect the copyright of image, non- watermark algorithm constructs marking meaning watermark by the characteristic structure of image instead of embedding watermark by altering the data of image. To improve the weakness of huge calculation and weaker robust ability in the existing algorithms, a new non - watermark algorithms based on wavelet domain is presented in the paper. The algorithm combines the quadtree decomposition of image, with making use of the characteristic of the lowest frequency coefficients in DWT domain to construct non - watermark. Experimental results show strong identification and good robust ability of this method.