数字水印的透明性的灰评判

Judgment of the Imperceptibility of Digital Watermarking Based on Gray Correlation Degree

鲁棒性和透明性是数字水印的两大基本特征,关于水印鲁棒性的检测一直受到人们的普遍重视,但水印透明性却没有定量的检测指标。论文将灰色系统理论中的灰关联概念首次引入水印技术中,提出了一种适用于评价水印透明性的算法。该算法把载体信号转化为参考序列,把加入水印后的载体信号转化为比较序列,通过灰色关联度的整体比较机制来对水印的透明度做出客观的定量的评价。实验证明,这种基于灰关联的评判结果与HVS判断结果一致,能够用来评判水印透明度。

Although robustness and imperceptibility are the most fundamental characteristics of digital watermarking,ro-bustness is always emphasized;while the latter is ignored.To estimate the imperceptibility,this paper applies gray corre-lation degree of gray system theory to digital watermarking,and proposes an algorithm that transforms the raw host sig-nal into reference sequence and the embedded host signal into comparative sequence.Quantitative and objective results of imperceptibility are achieved through over-all comparison mechanism of gray correlation degree.Finally,simulations,consistent with HVS,prove it an effective way to value imperceptibility of watermarking.