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:
Mar. 16, 1993
Filed:
Nov. 20, 1990
Dennis Quardt, Morris County, NJ (US);
Ker-Ming Chang, Mercer County, NJ (US);
Educational Testing Service, Princeton, NJ (US);
Abstract
A method for the optimization of optical scanners by automatically determining image processing threshold values using a novel threshold calibration sheet. The calibration sheet image has lines at a forty-five degree angle to the path of the document through the scanner and has a predetermined image dot count. One embodiment comprises the steps of repetitively scanning the sheet until scanner threshold values which satisfy predetermined relationships with said dot count are determined. Another embodiment comprises the steps of a single calibration scan with multiple processing of the gray scale scan data on a host computer. By using this method, two or more scanner cameras can work together on processing document images and consistently give uniform results, independent of their individual technical operating or performance differences.