Print-scan resilient data hiding scheme applied in certificate verification

A method to hide information into pictures in certificate that achieve robustness against printing and scanning is proposed. Aiming at three main distortions during the process of certificate manufacture, use and verification, the prediction error filter used in spatial watermarking. A kind of naturally robust watermark pattern is applied to resisting the local and small nonlinear distortion. The bigger geometric distortions are corrected by image registration based on Hausdorff distance.