一种新颖的用于图像内容认证、定位和恢复的半脆弱数字水印算法研究

A Novel Semi-fragile Digital Watermarking Algorithm for Image Content Authentication,Localization and Recovery

本文提出了一种半脆弱,分块和基于内容的数字水印技术.该算法可以准确的实现篡改区域的认证,定位和恢复.算法基于独立分块技术将用于认证的水印比特嵌入到每个块的Slant变换域的中频区域.嵌入过程是基于我们通过实验发现大部分的Slant中频系数的正负符号在非恶意操作前后保持不变这一性质.在恢复系统中,恢复比特来源于原图压缩后的数据并将此数据嵌入到图像的最低有效位以实现自恢复.认证度由虚警检测率和误警检查率测定.仿真实验表明我们的算法能够准确的检测和定位出篡改区域并能实现篡改区域的近似恢复.另外,与基于DCT和PST变换的算法相比,我们的算法能够更有效的抵抗一些恶意和非恶意操作同时实施的操作.

A semi-fragile,block-wise and content-based watermarking method for tamper detection and recovery is presented in this paper.The non-overlapping blocks are used and the watermark bits for authentication are embedded into the middle frequency region of each block in the ST Slant Transform domain.The embedding process is based on the discovery which the sign of the most ST coefficients maintain invariant.For the recovery mechanism,the recovery bits generated from the compressed original image are embedded into the least significant bits（LSB） of the watermarked image.The degree of the authenticity is measured by the false positive detection rate and false negative detection rate.Simulation results demonstrated that our method is able to accurately detect and localize the tampered region as well as approximately recover it.Furthermore,as compare with the DCT and PST based schemes,our proposed method obtains better performance when both malicious and non-malicious manipulations are applied together.