摘要
由于空间域嵌入的水印对旋转和缩放攻击相当脆弱,本文提出一种新的水印算法。将原图像和水印图像进行对数极变换,将变换后的水印图像嵌入到变换后的原图像中,然后再反变换为直角坐标系下的图像。水印嵌入到图片的位置不同,检测的水印图像发生变化。本文提出三种嵌入位置的方案,显示不同的效果。检测水印时,对几何攻击过的水印进行几何校正,然后与原图像相减得到水印。这种水印方案能够很好地抵抗几何攻击。
Because the algorithm of spatial domain image watermarking cannot resist the attacks of revolution ano zooming, we put forth a new watermarking algorithm. The original images and the watermarked images are transformed to logpolar images. The watermarked images transformed are added to the original images transformed. Then again the images watermarked are inversely transformed to the images in a 2D Cartesian coordinate system. When the watermarks are embed- ded in the different positions of an image, the watermarked images detected will vary. The paper presents three schemes about the embedding positions and shows different effects. While the watermarks are being examined, the watermarks attacked by geometric attacks should be dealt with by geometric correction. The watermarks can be obtained through an image subtraction. The new scheme is good at resisting geometric＇attacks.
出处
《计算机工程与科学》
CSCD
2008年第6期62-65,共4页
Computer Engineering & Science
关键词
数字水印
对极坐标变换
LSB法
几何攻击
digital watermarking
log-polar transform
LSB method
geometric attack
