基于改进SIFT的抗几何攻击的数字水印

通过改进的SIFT（尺度不变特征变换）算法提出了一种可有效抵抗几何攻击的鲁棒数字水印算法。此算法利用改进的SIFT进行水印信号的同步；水印嵌入采用圆环的嵌入模式，在空域以奇偶量化形式嵌入；通过奇偶检测器提取水印。实验结果表明，改进的SIFT大大降低特征点匹配的维数，提高匹配速率，同时该算法能获得很好的图像质量，能有效抵抗几何攻击和常规的信号处理攻击。

Geometrical attack digital watermarking based on improved SIFT

An effective against geometric attack robustness of digital watermarking algorithm based on improved SIFT（Scale Invariant Feature Transform） is presented.It achieves watermark synchronization using improved Scale-Invariant Feature Transform; watermark is embedded in cirque,using odd-even quantization in spatial domain and is extracted from an odd-even detector.Simulation results show that improved SIFT can reduce the matching dimension of feature point,improve the matching rate.And the proposed scheme achieves good image quality and it is robust to geometric attacks as well as traditional signal operations.