The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 18, 2005
Filed:
Jun. 17, 2001
Dan S. Bloomberg, Palo Alto, CA (US);
David L. Hecht, Palo Alto, CA (US);
Robert F. Tow, Palo Alto, CA (US);
L. Prasadam Flores, Woodside, CA (US);
Dan S. Bloomberg, Palo Alto, CA (US);
David L. Hecht, Palo Alto, CA (US);
Robert F. Tow, Palo Alto, CA (US);
L. Prasadam Flores, Woodside, CA (US);
Xerox Corporation, Stamford, CT (US);
Abstract
This invention provides self-clocking glyph shape codes for encoding digital data in the shapes of glyphs that are suitable for printing on hardcopy recording media. Advantageously, the glyphs are selected so that they tend not to degrade into each other when they are degraded and/or distorted as a result, for example, of being photocopied, transmitted via facsimile, and/or scanned-in to an electronic document processing system. Moreover, for at least some applications, the glyphs desirably are composed of printed pixel patterns containing nearly the same number of ON pixels and nearly the same number of OFF pixels, such that the code that is rendered by printing such glyphs on substantially uniformly spaced centers appears to have a generally uniform texture. In the case of codes printed at higher spatial densities, this texture is likely to be perceived as a generally uniform gray tone.Binary image processing and convolution filtering techniques for decoding such codes also are disclosed, but this application focuses on the codes.