基于置乱系统的脆弱数字水印算法

数字水印是一种用于数字产品版权保护的信息隐藏技术。本文提出一种基于混合视觉双稳态置乱系统的脆 弱性数字水印算法。该算法将图像分块，由各块亮度值确定混沌序列长度及嵌入深度，将各点位置信息、最高有效位颜色信息 以及自定义的密钥作为混沌系统的初值，各块不同深度地将水印序列嵌入图像各点的R、G、B 分量中；在检测定位时，比较提 取的水印和生成的水印，直接得到差异图像。实验结果表明，使用该方法嵌入水印后图像质量高，且篡改定位能力强。

A Fragile Watermarking Algorithm Based on Chaotic System

Digital watermarking is a kind of technology of hiding technology which is used to protect the copyright of digital products. In this paper, a new fragile digital watermarking algorithm based on hybrid visual bistable system is proposed. It divides the image into non-overlapped blocks, calculates the luminance of each block to decide the embedding depth and the length of chaotic sequence. For each pixel, an initial value is determined based on its prominent chrominance value, the position index, and the image protection key. Watermarking sequence is embedded into the embedding space of R,G,B respectively. Then it detects the temper by comparing the extracted watermarking and the produced one, until the error image is attained. Theoretical analysis and experiment result show that this algorithm is in high quality and locates the tamper position exactly.