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:
Sep. 04, 2001
Filed:
Apr. 08, 1999
Phillip W. Dennis, Thousand Oaks, CA (US);
Stuart A. Mills, West Hills, CA (US);
Robert B. Dydyk, Newbury Park, CA (US);
Litton Systems, Inc., Agoura Hills, CA (US);
Abstract
The invention corrects for rotational misalignment of images having a prominent periodic structure in a preferred direction, particularly imaged text pages. It preferably also finds the degree of correlation between different images. First the rotational misalignment of an imaged page is detected and corrected, bringing the page into alignment with an axis. The angle of rotation of the page is detected by performing a linear regression analysis on filtered, two-dimensional power spectral density distribution of the page, to find the angular orientation of the periodic components. In the preferred embodiment, two imaged pages are then cross-correlated, preferably by an optical correlator, to find the degree of correlation between the pages.