Information Embedding Method for Home Printing of Certifications

Abstract

In this paper, we describe our dot-pattern code, which can embed information onto the paper. Its main features are 1) no need to reserve a special room for the code, 2) obscure and unnoticeable, 3) comparatively large information capacity, 4) the absolute coordinates in the paper is measurable. We describe how to embed and detect the information onto / from the paper, and we estimate it by examination. From the examination, we found that our dot-pattern code is applicable to various kinds of papers, printers including ink-jet and scanners. We also found that even when the density of the black dot is greater than 6%, over 8,000 bits could be safely embedded with error rate less than 10-6. We also found that the embedded information could be detected correctly after the paper had been damaged.

A Feature Extracting Method for Tamper Detection in Printed Documents

“…To embed the feature value into the Document, we use the dot-pattern code (Takahashi 2007(Takahashi , 2008, which the authors have developed before. The dotpattern code is the information embedding method onto the paper with minute dots.…”

Recognition of Watermark Dot Information from a Folded, Rumpled, or Waved Paper

“…Recognition rate of the conventional background texture watermark recognition method [3] (hereafter referred to as "conventional method") is from ca. However, variability of intensity may decrease when a paper includes convex folds and concave folds which together serve as neutralizing factors.…”

“…As to the state of paper surface, however, folds and wrinkles are the main features of the state of paper surface. Accordingly, the state of paper surface is roughly categorized in above (1), (2), and (3).…”

“…However, variability of intensity may decrease when a paper includes convex folds and concave folds which together serve as neutralizing factors. Recognition rate of the conventional background texture watermark recognition method [3] (hereafter referred to as "conventional method") is from ca. 90% to ca.…”