作为多媒体认证和篡改检测的一种新技术,易碎水印正得到越来越多的关注.基于小波变换,结合量化调制过程,本文提出了一个易碎水印算法.该算法具有以下特点:(1)构造水印金字塔,便于实现水印的多分辨率检测;(2)结合视觉特性量化调制,尽可能减小视觉失真;(3)结合图像融合技术的多分辨率检测,使检测结果更准确;(4)抵抗一定程度的JPEG有损压缩.为了实现篡改的检测,本文给出了一个攻击判别方案,以区分恶意攻击和偶然攻击.实验表明,嵌入的水印在脆弱性和鲁棒性上达到了较好的统一,能够抵抗一定程度的压缩而不影响篡改检测的精确性.

As an effective method for multimedia authentication and tamper detection,fragile watermarking is drawing extensive attention recently.In this paper,we propose a novel fragile watermarking scheme based on HVS in DWT domain.By use of a specifical modulation,we embed the mark into the DWT coefficients of the original image.The features of proposed algorithm are as follows: i)The algorithm constructs a pyramid structure of the watermark for multi-resolution tamper detection; ii)According to the visual model,the algorithm modifies the coefficients to reduce the perceptible distortion; iii)The algorithm presents a new scheme for tamper detection by using image fusion.We propose several rules to distinguish the type of tamper between mild distortion and severe distortion.The experimental results demonstrate that the watermarks generated with the proposed algorithm can give the precise result of tamper detection when the image has been suffered from malicious tamper while tolerating JPEG lossy compression to a certain extent.