摘要： 几何攻击是制约水印技术实用性的重要因素，当图像经过旋转、缩放和DA 转换等几何变换后，绝大多数水印算法的检测器将失效。该文提出一种新的基于计算机视觉理论的图像空域特征重同步算法，首次采用图像的corner 中心角和corner 中心距离对水印图像几何失真进行失真校正。实验证明，算法性能良好、校正精度高、可以有效地校正大强度几何失真。

关键词: 数字图像水印；几何失真；corner 中心角；corner 中心距离

Abstract: Geometric distortions are critical factors which hamper the application of the image digital watermarking. While the image experienced the geometric transform such as resizing, rotation, DA translation, most of the watermarking technique would failed. In this paper a novel geometric distortions correction schema for image is proposed, it takes the advantage of the corner center angle and corner certer distance firstly to acquire geometric distortions correction. The experiments demonstrate that this schema has good performance, sound correction precision, and can correct high intensity geometric distortions.

Key words: Digital image watermarking; Geometric distortions; Corner center angle; Corner center distance