The FRFT has signal representation property both in space and frequency domain.The original image and the wate-rmark is transformed with different orders to improve watermarking security.

• 分数傅里叶变换具有空域和频域双域表达能力,可以对原始图像和水印信号分别进行不同阶次的分数傅里叶变换以增强水印安全性。