| US 7,520,443 B2 | ||
| System, method, and program for extracting invisible information | ||
| Koichi Kamijoh, Yokohama (Japan); Noboru Kamijoh, Fujisawa (Japan); Junji Maeda, Tokyo (Japan); and Masaharu Sakamoto, Yokohama (Japan) | ||
| Assigned to International Business Machines Corporation, Armonk, N.Y. (US) | ||
| Filed on Dec. 15, 2006, as Appl. No. 11/611,733. | ||
| Prior Publication US 2007/0138286 A1, Jun. 21, 2007 | ||
| Int. Cl. G07K 19/06 (2006.01) | ||
| U.S. Cl. 235—494 [235/462.42; 235/472.01] | 3 Claims |
| 1. A method for extracting invisible information from an object formed by overlapping visible information with a least part
of invisible information formed in a stealth ink, comprising:
a step of irradiating the object with light for making the stealth ink luminous;
a step of receiving reflected light from the object;
a step of extracting image information from the received reflected light;
a step of storing the image information;
a step of splitting the image information into a plurality of color channel information;
a step of obtaining a correlation function and broadening pixel values between color channel information on at least one pixel
value that forms an image information, for at least two color channel information selected from the color channel information;
a step of reducing a visible information component of one selected color channel information using the correlation function,
to perform interpolation, raising image information of the stealth ink and reducing non stealth-ink image information; and
a step of extracting invisible information from an interpolated one color channel information by the steps of:
extracting a position detection pattern;
extracting an alignment pattern;
correcting distortions with the alignment pattern;
digitizing colors of cells; and
determining bit information of the cells from the color channel information after alignment.
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