一种基于混合域自适应灰度水印算法

An adaptive grey-level digital watermarking algorithm based on DWT and DCT domains

为了在保证图像质量的前提下实施图像的版权保护,文章给出了一种新型的离散小波变换(DWT)和离散余弦变换(DCT)相结合的自适应灰度数字水印算法。该算法先对原宿主图像进行离散小波变换,选择中频部分作为待嵌入子带,然后对待嵌入子带分块并进行离散余弦变换,在每块包含DC分量的低频系数和部分中频系数上嵌入水印。此算法集DWT的多分辨特性和DCT的聚能作用以及去相关能力的共同优点;实验结果表明,该方法具有实用性强、鲁棒性好及可操作性强等优点。

In order to achieve protection of the copyright of an image while the image quality is kept,a new kind of adaptive grey-level digital watermarking algorithm which combines DWT with DCT is brought forward. According to DWT of the original unmarked image,the HL and LH are selected as the parts to be embedded and plotted into small block images,and then DCT is carried out. The watermarking image is embedded in the low frequency coefficients containing DC components and the parts of middle frequency coefficients. This algorithm coalesces the multi-resolution effects of DWT and the energy compressing and decorrelation capacity of DCT. The results of experiment indicate that this algorithm has many advantages in practicability, robustness,and maneuverability.