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:
Aug. 24, 1993
Filed:
May. 06, 1991
Gregory F Russell, Yorktown Heights, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A digitizer tablet (10) has an array of conductors that define a sensing plane (12) for sensing an electromagnetic signal generated by a pointing device (16) disposed external to the plane. The tablet includes circuitry, coupled to the array of conductors, for determining a magnitude of an electrical signal or signals induced within the array of conductors by the pointing device. The tablet also includes a data processor (30) that is responsive to the determined magnitude for accurately estimating both a position and an angular orientation of the pointing device relative to a coordinate system associated with the sensing plane. A first position estimate derived from a zero-crossing estimator is used to position a weighting function, which is employed in a weighted least squares fit of a line to the data, resulting in a second zero-crossing estimate of the position of the pointing device. On this second position estimate another weighting function is centered and a tilt estimation is obtained. The tilt estimation is employed to derive a correction for the position estimate.