中文摘要：

提出一种基于复Hadamard变换的盲数字图像水印算法．复Hadamard变换系数具有重要的半谱特性，利用复Hadamard变换这一独特性质嵌入一幅二值水印图案．为了增加水印的稳健性，采用（7，4）汉明编码将水印的校验图也嵌入到复Hadamard变换域中．特别是，水印图案的提取不需要原始图像．实验结果表明：这种方法对迭加噪声、JPEG压缩、滤波、剪切、图像增强、马赛克等常见攻击具有很好的稳健性。

英文摘要：

Proposed was a method for embedded watermarks in digital images based on complex Hadamard transforms, whose transform coefficients are characterized by important half spectra property （HSP）. According to this half spectra property, a binary logo was embedded into the complex hadamard transform domain of an image. The watermarked images were recovered without original images. （7,4） Hamming code was used to encode the watermark to improve its robustness, and also embed its verified pattern into the complex hadamard transform domain of an image. Especially, the wa- termark recovery does not require the original image. The experimental results show that our scheme is robust to variety of attacks such as adding noise, PEG compression, filtering, cropping, image en- hancement and mosaic.