一种新的抗JPEG压缩半脆弱图像水印算法

半脆弱水印因为在多媒体内容认证方面的重要作用而受到人们密切的关注。为了能够区分恶意篡改与偶然操作,半脆弱水印要求对常用的内容保护图像操作应具有一定的鲁棒性。由于JPEG压缩在图像处理的广泛应用,对恶意篡改攻击具有较高的检测能力,半脆弱水印研究的一个重要问题是提高抗JPEG压缩性能。该算法首先图像小波高频子带系数LH2,HL2分别进行分块,然后算出分别每块的系数的能量值,根据能量系数之间的大小关系嵌入水印信息。实验测试表明,所提出的算法不会影响图像的主客观质量,有很好的抗JPEG压缩性能,而且可嵌入的水印信息量大,并且能够准确确定恶意攻击的位置。

A SEMI-FRAGILE IMAGE WATERMARKING RESISTING TO JPEG COMPRESSION

Semi-Fragile watermark has attracted attention due to its important role in content authentication for multimedia.In order to differentiate incidental attacks and malicious attacks,semi-fragile watermark should be robust against content-protection image processing.Semi-fragile watermark resisting to JPEG compression while maintaining high detection ability to tamper has been the emphasis in the area.This algorithm of image wavelet coefficient LH2 and HL2 was blocked and computed each of block coefficient energy based on the relative energy relations embedded watermark.Simulation experiments prove that it will not degrade the objective and subjective quality of original images,the good robustness to JPEG and the larger amount of embedded information.What’s more,it can ascertain the position of vicious attack exactly.