DCT域中DC分量上嵌入水印的稳健性检验

在DCT域中,通常将水印嵌入到AC分量上,特别是在中频系数上。近来,有学者提出:图像经过DCT变换后,它的直流分量的感觉容量比交流分量大。从稳健性的角度,DC分量最适合用来嵌入水印。该文旨在用实验进一步验证这一论点。实验结果表明,DC分量上嵌入隐形水印的策略是有效的,并且具有很好的稳健性,能抵御施加在已嵌入水印的图像上的裁剪、有损压缩、增加亮度和对比度的攻击。

A Robust Test for Watermarks Embedded in DC Components in DCT

In DCT domain,the traditional means is to hide watermarking in the AC components,especially in the mid-dle-frequency coefficients.Recently,some scholars argue that more robustness can be achieved if watermarks are embed-ded in DC components since DC components have much larger perceptual capacity than any AC components.The au-thors aim at verifying this argument further by means of experiments.Experimental results demonstrate that the strategy,which embeds watermarks in DC components,is effective and the invisible watermarks thus generated are very robust,and images embedded watermarks can withstand attacks which are exerted by tailoring,loss compression,enhanced brightness and enhanced contrast.