基于Curvelet变换的印刷防伪数字水印算法

Curvelet-Based Digital Watermarking Algorithm for Printing Security

添加数字水印是一种常见的印品防伪技术,本研究从数字水印的鲁棒性与不可感知性角度出发,基于Curvelet变换的多方向、多分辨、带通特点及各层的系数特征,提出了一种基于Curvelet变换的印刷防伪数字水印算法。首先,对数字水印图像进行预处理;其次,对原始图像进行Curvelet变换;然后,将置乱后的水印图像嵌入到Curvelet变换后的中高频Detail尺度层中,在保证嵌入图像的不可感知性和鲁棒性的前提下,寻找到较优的水印嵌入位置和嵌入强度,从而完成水印的嵌入。仿真实验表明,该算法简单有效,嵌入到彩色图像中的水印不仅可经打印、扫描和预处理后准确提取,且即使对嵌入水印的图像进行加噪、JPEG压缩、裁剪等攻击,其仍具有较强的鲁棒性。

The anti-counterfeiting printing can be achieved by embedding the digital watermarking.In this study,in terms of requisition of imperceptibility and robustness of watermarking,based on the multidirectional,multiscale and band-pass coefficient features of Curvelet transform,a kind of new Curvelet-based digital watermarking algorithm for printing security was proposed.Firstly,a watermarking image was preprocessed.Next,the original image was decomposed into frequency domain by using Curvelet transform.Then,digital watermarking was embedded in the detail scale coefficients.The digital watermarking that embedded in a color image can be extracted after printing,scanning and preprocessing.The experimental result demonstrated that watermarking extraction's effect is acceptable.Moreover,severe image attacks such as noise,image crop and JPEG compression and so on were survived by the embedded watermarking.