Estimating and undoing rotation for print-scan resilient data hiding
This paper proposes a method to hide information into images that achieves robustness against printing and scanning with blind decoding. A significant contribution of this paper is a technique to estimate and undo rotation. The method is based on the fact that laser printers use an ordered digital halftoning algorithm for printing. Using the proposed hiding method, several hundred information bits can be embedded into 512/spl times/512 images with perfect recovery against the print-scan operation. Moreover, the hidden images also survive other attacks such as Gaussian or median filtering, scaling or aspect ratio change, heavy JPEG compression, and rows and/or columns removal.