A system for tracking and tracing secure documents is described by embedding print job data on each page in a steganographic halftone, preserving the aesthetics of the page. The system demonstrates the ability to transmit job tracking data with perfect accuracy using data hidden in a high-quality rendering of a graphics object. This work addresses two key issues: (1) control of halftoning edge eflects for graphic objects like logos, and (2) compensation for non-afline warping efiects induced by the print-scan process. The solution eliminates noisy edges without sacrificing data-carrying capacity in natural images, while providing automated alignment and robust recovery with the use of error correction codes.
Robert Ulichney, Matthew Gaubatz, "Tracing the Source of Printed Documents with Edge-Refined Stegatones" in Proc. IS&T Int'l Conf. on Digital Printing Technologies and Digital Fabrication (NIP27), 2011, pp 700 - 704, https://doi.org/10.2352/ISSN.2169-4451.2011.27.1.art00076_2