DWT域图像水印的精确嵌入与盲检测的实现

文章提出了一种用于版权认证的基于小波变换的盲图像水印算法,该算法首先从低频子带中选择N个大系数作为嵌入区间,用它们的的低5位表示水印信息;在嵌入过程中,该算法根据小波变换所具有的良好的空域局部化特性,采用了分块舍入技术,实现了水印信息的精确嵌入;在检测过程中,文章提出了一种新颖的差分检测方法,替代了传统的位置检测方法,既简化了检测过程,又增强了系统的鲁棒性。实验结果证明,该算法具有嵌入信息量大,水印透明性好,对各种常见的图像处理操作、有损压缩、裁剪和几何变换抵抗性强等特点。

A Realization of Precise Embedding and Blind Detecting for Image Watermarking in DWT Domain

In this paper,a new blind image watermarking algorithm based on Discrete Wavelet Transform(DWT) is pro-posed,which can be used in copyright authentication.We firstly select N coefficients from the approximate coefficients to be the embedding domain,then use their least 5 bits to embed the watermark.Considering the localization character of wavelet transform in spatial domain,we use block rounding to increase the embedding precision.As to the detecting algorithm,we propose a novel difference detecting algorithm,taking place of the traditional position-detecting algorithm.It not only simplifies the detecting course,but also improves the robustness of this system.The experimental results show that this algorithm has the following characters:large information capacity,invisibility and robustness against some common image processing operations,lossy compression,cropping and some geometric transformations.