空域中实现基于DC系数的图像水印算法*

针对多数图像水印算法是在单一的空域或频域中执行的现状,提出一种结合两者优点的彩色图像盲水印算法。根据DCT域中DC系数的形成原理,在空域中直接求得亮度分量Y中8×8子块的DC系数并建立其量化表;在空域中通过直接修改像素值实现在DCT域中修改DC系数来嵌入水印的目的。水印的提取不需要原始水印和原始宿主图像。实验结果表明,该算法既有频域算法鲁棒性高的优点,又有空域算法执行效率高的优点。

Image watermarking algorithm based on DC components implementing in spatial domain

It was noted that most of the existing watermarking algorithms were performed only in the single spatial domain or frequency domain, this paper proposed a novel blind watermarking algorithm which combining with both advantages for color host images. By utilizing the generating principle and the distribution feature of direct current (DC) coefficient in DCT transformation, firstly, it calculated the DC coefficient of each 8×8 block of the Y luminance directly in spatial domain to create the quantization table. Then, it modified all pixel values of each block to embed watermark in the spatial domain instead of in the DCT domain. In addition, the watermark might be extract from the watermarked image without the original watermark and the original host image. Experimental results show that the proposed method not only has the higher robustness that is the advantage of frequency domain, but also has lower-computation complexity that is the advantage of spatial domain.