关键词: 数字水印 对极坐标变换 LSB法 几何攻击

Abstract:

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 ima  ges 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 posit   ions and shows different effects. While the watermarks are being examined, the watermarks attacked by geometric attacks should be dealt with by geometri c correction. The watermarks can be obtained through an image subtraction. The new scheme is good at resisting geometric＇attacks.

Key words: digital watermarking, log-polar transform ;LSB method, geometric attack