提出一种同时具有版权保护和内容认证双重功能的JPEG图像水印算法,其中版权保护通过嵌入固定信息,内容认证通过嵌入内容特征码来实现,算法中特征码具有“半脆弱”特性.水印嵌入算法借鉴DEW的算法原理,并结合特征生成的需要,提出了一种改进方法.在DCT域中选择低频部分用来生成特征码,高频部分用来嵌入水印,最后给出的实验结果证明了算法的有效性.
A JPEG image watermark scheme with copyright protection and content authentication is proposed. Copyright protection is achieved by embedding some fixed data. Content authentication is achieved by embedding the authentication code with the "semi-fragile" property. An improved watermark embedding algorithm is proposed according to the need of feature forming by using DEW scheme. The lower DCT region is used to form feature code while the higher one is used to embed watermarks. An experiment on image object demonstrates the effectiveness of the scheme.