Stegatone performance characterization
Yung-Yao Chen, Robert A. Ulichney, Matthew D. Gaubatz, Stephen B Pollard, Chun-Jung Tai, Jan P. Allebach · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2013
Embedding data in hard copy is in widespread use for applications that include pointing the reader to on-line content by means of a URL, tracing the source of a document, labeling, and packaging. Most solutions involve placing overt marks on the page. The most common are 1D, 2D, and 3D (color) barcodes. However, while barcodes are a popular means for encoding information for printed matter, they add unsightly overt content. In order to avoid such overt content, Stegatones are clustered-dot halftones that encode a data payload by single-pixel shifts of selected dot-clusters. In a Stegatone, we can embed information in images or graphics – not in the image file, as is done in traditional watermarking, but in the halftone on the printed page. However, the recovery performance of stegatones is not well understood across a wide variety of printing technologies, models, and resolutions, along with variations of scanning resolution. It would thus be very useful to have a tool to quantify stegatone performance under these variables. The results would then be used to better calibrate the encoding system. We develop and conduct a test procedure to characterize Stegatone performance. The experimental results characterize Stegatone performance for a number of printers, scanners, and resolutions.