A Method for Embedding Information into Printed Documents using Dot Pattern Watermarking
Junichi Matsuda, Tomoya Miwa, Ken Matsuda, Yoshiki Mizukami, Katsumi Tadamura · ITC-CSCC :International Technical Conference on Circuits Systems, Computers and Communications · 2009
We propose a method for embedding information into printed documents. The method is using dot pattern watermarking based on illustration so that impression of documents is natural. Since random dots are used for conventional dot pattern, documents with dot pattern often give strange impression to readers. Our method is to use dot pattern image transformed from illustration image. We developed two key techniques; one is a method for transforming illustration image to dot pattern image suitable for watermarking; another one is a method for embedding information that can reduce noise caused by errors when printing and scanning documents. We verified the impression of printed documents with dot pattern generated by the proposed method by subjective experiments.