目的 为了提高抗几何攻击水印算法的鲁棒性，提出一种新的SIFT几何校正的抗几何攻击水印算法。方法 利用尺度不变特征变换算法分别提取原始图像和受几何攻击图像的特征点，在水印提取前，将原始图像和受几何攻击图像进行特征点匹配，按照匹配的特征点对受几何的攻击图像进行几何校正。在水印嵌入过程中，结合奇异值分解(SVD)特征值的稳定性和非负矩阵分解(NMF)线性无关性来增强水印图像的鲁棒性。结果 文中算法在剪切、JPEG、噪声等攻击下具有很好的鲁棒性，提取出来的水印图像NC值均大于0.98，在RST攻击下水印图像的NC值也能达到0.97以上。结论 提出的抗几何攻击算法能有效的抵抗各类几何攻击，具有很好的鲁棒性。

The work aims to improve watermarking algorithm robustness against geometric attack and propose a new watermarking algorithm against geometric attack based on SIFT geometric correction. First, the feature points of the original image and attacked image were respectively extracted with SIFT. Before watermark extraction, the feature points of the original image and attacked image were matched and the geometric correction of the attacked image was carried out based on the matched feature points. In the embedding process, the robustness of the watermark image was enhanced in combination with the stability of the singular value decomposition (SVD) eigenvalue and the linear independence of non-negative matrix factorization (NMF). The algorithm in the paper was robust in shear, JPEG, noise and other attacks, and the NC value of the extracted watermark was higher than 0.98. The NC value of watermark image under attack of RST could also reach over 0.97. The proposed algorithm against geometric attack can resist all kinds of geometric attacks effectively and also is robust.