一种基于chirp信号的空间域鲁棒性水印算法

选取两个chirp信号作为水印信息,嵌入到图像空间域中与该信号有相同数字特征的像素点处,使用两个嵌入位置矩阵作为算法密钥的同时,还根据chirp信号在分数傅立叶变换域呈现冲激的特征来检测水印信号。仿真实验结果表明,该数字水印算法具有良好的不可见性和安全性,算法不仅能抵抗很强的JPEG压缩、加噪、滤波等常用的信号处理操作,对旋转、平移、剪切等几何攻击也有很强的鲁棒性。

A robust algorithm for digital watermarking using chirp signals in the spatial domain

A novel algorithm for digital image watermarking which uses two chirp signals as the watermark in the spatial domain is presented.Chirp signals are embedded in the image blocks that have the same digital character.Two matrices of the position where the watermark is embedded are used as the encryption keys in this algorithm.With the help of the property that a chirp signal can produce a strong impulse in the FRFT domain,the watermark can be detected conveniently.Results of the experiments show that this algorithm is not only very robust to JPEG compression,noise and filtering attacks,but also can provide good protection under common geometric at-tacks of rotation,translation and cropping,and assure good imperceptibility and security.