一种用于图像认证的半脆弱性数字水印算法*

由图像Harr小波变换的高频系数构造加密序列，对加密序列进行均值量化操作以嵌入或提取水印；量化参数可以根据窜改的灵敏度要求来设置。实验结果表明该算法具有良好的视觉透明性，可对图像内容的恶意窜改进行精确的检测和定位，并且能够忍受多种通用信号处理如亮度调整，线性滤波等带来的失真。

A New Semi-fragile Watermarking Algorithm for Image Authentication

The watermark can be embedded or extracted by the mean quantization operation of the encrypted sequence constructed by the high frequency coefficients in the Harr wavelet transform domain, and the mean quantization parameters can be adjusted according to the sensitivity requirements. The experimental results demonstrate that the proposed algorithm has good perceptual transparence. The malicious modification can be distinguished from the common image processing such as brightness adjustment, linear filtering and so on, while the tampered area can be located exactly.