结合Zernike矩和水印的半脆弱图像认证

Semi-Fragile Image Authentication Based on Zernike Moments and Watermark

水印安全性、抗JPEG的鲁棒性和篡改检测能力的矛盾、计算复杂度是现有基于数字水印的半脆弱图像认证算法需要克服的主要问题．本文提出一种结合Zernike矩和水印的图像认证算法．利用图像小波变换低频子带的Zernike矩幅值的半脆弱特性区分恶意攻击和偶然攻击．结合基于HVS(人类视觉系统)的水印后,可判断图像是否受到伪认证攻击,提高了水印安全性．通过采用基于提升格式的整数小波变换,有效降低了算法计算复杂性．实验结果表明,算法对较低质量因子的JPEG有损压缩鲁棒,对剪切、替换等恶意修改敏感且可准确定位篡改位置．

How to ensure watermark security, how to overcome the contradiction between robustness and JPEG lossy compression, how to cancel out the contradiction between fragility and malicious tamper, and how to reduce the computational complexity are the main issues to be solved in the existing semi-fragile image authentication algorithms based on watermark technique. In this paper, a semi-fragile image authentication algorithm using Zernike moments and watermark is proposed. It can distinguish malicious modification from incidental modification according to semi-fragile characteristics of Zernike moments of the low frequency subband in the integer wavelet transform domain of an image. Combining the semi-fragile characteristics of Zernike moments and the watermark based on human visual system, it can discern counterfeit attack, thus, improving watermark security. Computational complexity is reduced by integer wavelet transform using lifting scheme. Experimental results show that the proposed algorithm tolerates JPEG lossy compression to a large extent, and meanwhile it is fragile to malicious tamper and capable of locating the tampered area accurately.