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:
Dec. 21, 1999
Filed:
Dec. 05, 1997
Myungsae Son, Rancho Santa Fe, CA (US);
John M Weldon, San Diego, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A technique for document edge detection in an optical scanning system. The document is placed against an over-sized neutral background. A linear optical sensor array is used to provide successive lines of pixel data representing the luminance of detected pixel areas. Commencing from one end of the line of pixel data, for successive current pixels being tested, a group of n adjacent pixel values is correlated with a successive group of n adjacent pixel values to provide a correlation value for the current pixel. One of the groups is assumed to contain only background pixels, and their luminance is approximated to be equal to the average luminance over the entire background. If the correlation value exceeds a threshold constant, the current pixel is chosen to be an edge in this line of pixels. Data from several lines is processed to find corresponding edges for each line, and the line edges are subjected to a least squares fit to calculate the location of the document edge. The left and right edge of the document can be found using this technique. A histogram of luminance values for each line of pixel data is analyzed to determine whether an edge value is valid.