基于DCT域的数字图像双水印算法

提出了一种基于DCT域的数字图像双水印算法,将鲁棒水印与脆弱水印同时嵌入到DCT的中低频系数中,鲁棒水印和脆弱水印的嵌入与顺序无关,且不相互影响.首先,对DCT变换后的系数按照它们的位置进行了特殊的分类,通过分类后每一类中正负号的数量来表达鲁棒水印信息,增强了算法的鲁棒性.对相同的DCT 系数使用邻近值比较法嵌入脆弱水印.实验结果表明鲁棒水印可以实现了对图像载体的版权认证,脆弱水印实现了对图像载体的完整性保护和篡改定位.

A Digital Image Double Watermarking Algorithm Based on DCT Domain

In this paper,a new digital image double watermarking algorithm based on DCT domain is proposed.The robust and fragile digital watermarking are embedded on the DCT mid-low frequency coefficients of image at the same time.The robust and fragile digital watermarking has nothing to do with its order and has no influence on each other.First,the DCT coefficients are classified by their position.After classification,the robust digital watermarking is expressed by the count of difference between the positive and the negative in each group,and the robustness is enhanced.The fragile digital watermarking is embedded on the same DCT coefficients by the scale quantization function.Experiments show that the robust digital watermarking of this algorithm can be used in copyright protection,and the fragile digital watermarking provides a convenient tool for tampering detection and verification of image integrity.