一种能区分水印或内容篡改的脆弱水印算法

An Image Authentication Scheme with Discrimination of Tampers on Watermark or Image

针对目前脆弱水印算法大多无法区分水印被篡改还是内容被篡改的问题,本文基于多重水印技术提出了一种能区分水印或内容篡改的脆弱水印算法.该算法由子块的主要DCT系数生成恢复水印,将其嵌入到偏移子块的次低位;待恢复水印嵌入后,将恢复水印作为子块内容的一部分生成认证水印,将其嵌入到子块的最低位.理论分析和实验结果表明:本文算法在抵抗量化攻击的同时,不仅能准确定位图像内容被篡改的位置,而且能区分是水印被篡改还是图像内容被篡改,并且在一定条件下可以对内容被篡改的区域进行恢复.

The existing fragile watermarking algorithms almost can＇t recognize the modification made to the watermarked image is on the image content or on the embedded watermark. In this paper, a novel fragile watermarking scheme is proposed. The recovery watermark of each block is embedded into the Hypo-LSB of the corresponding excursion block selected by a key,and the authentication watermark of each block is embedded into its LSB. Theoretical analysis and simulation results show that the proposed algorithm can not only thwart the VQ attack and locate tampered blocks accurately, but also discriminating tampering watermark from that of content. And in some case, it can restore the tampered region effectively.