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. 23, 1993
Filed:
May. 02, 1991
Larry A Blue, Durham, NC (US);
Bruce T Freedman, Cary, NC (US);
Jose F Gonzalez-Heres, Miami Beach, FL (US);
Alexander G MacInnis, Chapel Hill, NC (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and apparatus that distinguish a valid touch from an optical aberration caused by unwanted objects and/or scratches in the light plane of an optical touch panel device is disclosed. During a training mode the device learns the relative position of 'aberration dropouts' caused by the unwanted objects. During normal operating mode the relative positions of 'touch and aberration dropouts' are generated and compared with the relative position of aberration dropouts to distinguish between aberration dropout signals and touch dropout signals. The touch dropout signals are subjected to further processing to determine the precise location of a touch while the aberration dropout signals are discarded.