几种图像数据隐藏方法的比较研究

Comparative Study of Some Image Data Hiding Methods

近年来,图像数据隐藏技术得到了突飞猛进的发展,得到了很多鼓舞人心的成果。在图像隐藏技术中,使用最多的图像嵌入规则有三种:加法嵌入规则、乘法嵌入规则以及基于融合技术的图像嵌入规则。本文对这三种图像嵌入规则的性能进行了分析和研究,通过比较我们发现,如果将图像隐藏过程看作是一个水印信道模型,则基于融合技术的图像嵌入规则所能隐藏的信息量远远高于另两种嵌入规则,而乘法嵌入规则其水印信道容量不受原始图像DCT系数标准差变化的影响,因此,在原始图像DCT系数标准差不稳定的情况下,采用乘法嵌入规则是一个好的选择。

Though image data hiding (Digital watermarking) as a tool for copyright protection is quite recent, a great deal of research has been carried out mainly addressing the development of robust, yet unperceivable, watermarking strategies. As it is now becoming evident, however, other important issues have to be analyzed in order to make watermark-based copyright protection feasible. Among them, the analysis and comparison of the performance of additive embedding method, multiplicative embedding method and fusion embedding method plays a mayor role. In this paper, the watermarking is assumed to consist in the modification of a set of full-frame DCT coefficients. The watermark channel is modeled by letting the watermark be the signal and the original image DCT coefficients the noise introduced by the channel. To derive the capacity of each coefficient, the channel transition matrix is computed. An evaluation of the number of bits that can be hidden within an digital image by means of frequency domain watermarking, using three embedding methods respectively, is given. These computative results are derived by using three embedding methods, respectively. Experimental results show that the performance of fusion embedding method is the best.