基于双重水印的数字版权保护算法

Digital Copyright Protection Based on Dual Watermarking Algorithm

可见水印是指在电子文档中视觉上可见并且包含作者信息的数字水印,因此在一定的条件下它可以阻止特定信息的非法复制.但是在载体图像中呈现的可见水印却很容易被移除,因为本质上它是被使用者察觉的.克服这种问题的一种方法是加入不可见水印,它对水印信息的去除具有鲁棒性.然而,根据需求嵌入的两种不同类型水印会引起相互间的干扰,最终会降低这两种类型水印性能.因此,文章提出了一种基于频率滤波的算法,该算法将载体图像划分为两种不同类型的区域,一种类型用于嵌入可见水印而另一种用于嵌入不可见水印.并将可见水印嵌入到低频区域,而不可见的水印嵌入到中高频.实验结果表明,该双重水印算法在图像质量方面比传统的水印算法表现出较好的性能.

Visible watermark is visible on the vision in the electronic document and contains the author information,under certain conditions it can prevent illegal copying of specific information.However,the message presented by an emerged watermark is easily removed from the copied content because it is visible to the copier.One way to overcome this problem is to also use invisible watermarks which are robust against removal.However,mutual interference caused by embedding two different types of watermarks would degrade the performance of both types.A method has thus been developed in which frequency filtering is used to divide the content into two types of region,one for embedding an visible watermark and one for embedding invisible one.The visible one is embedded in a plain large region with low spatial frequency while the invisible one is not.Experimental evaluation demonstrated that image quality in the dual watermarking algorithm shows better performance than the traditional watermarking algorithm.