After analyses the distortion of pixel values and geometry during the PS process, we achieve the RST (Rotation, Scale, Translation) invariants using characteristics of Fourier transformation, and extract secret information successfully.

• 针对PS(Print-Scan)过程引起的图像像素失真及几何失真，我们利用傅立叶变换的特性，得到RST(Rotation，Scale,Translation)不变量，解决了纸质二值图像中的信息隐藏问题。