中文摘要：

为了消除基于分块的图像认证算法中图像块之间的相关性,并进一步减小自嵌入水印对载体图像质量的影响,提出了一种新的自嵌入易碎水印算法：首先对图像进行2×2的分块,并求各分块的灰度均值生成图像的均值图像；根据均值图像各像素之间的相关性进行游程编码；将编码信息作为水印嵌入在图像像素的低位中；篡改检测时首先使用字符串匹配的思想进行图像块和水印之间的匹配,对于未匹配成功的块,使用分组的方式进行再次匹配,以完成认证和恢复.该算法进行一次的水印嵌入,同时用于篡改检测与恢复,有效缩短了水印长度,减小了对载体图像质量的影响.理论分析和实验仿真表明了文章算法在不可见性、篡改定位和恢复、抗拼贴攻击、漏检率等方面具有较好的效果.

英文摘要：

Existing fragile watermarking algorithms based on blocks can not avoid the autocephaly between the blocks drastically. Tosolve the problem, a novel variable-payload self-embedding fragile watermarking algorithm is proposed. The original image is divided into 2 × 2 blocks firstly, and the average value of each block is calculated. By the relativity between the average values, the algorithm encodes them statistically,and embed the code into 2-LSB of the image. In authentication, the algorithm uses string matching to match the blocks and the watermark. For the unmatched blocks, grouping is adopted to re-match. Theoretical analysis and simulation results show that the proposed algorithm can not only thwart the collage attack and locate tampered blocks accurately, but also has better non-visibility.