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. 28, 1989
Filed:
Dec. 03, 1981
Philip V Coates, Sunbury-on-Thames, GB;
EMI Limited, Hayes, GB;
Abstract
A focussing system in which a detection and processing device (2) scans the image plane, in raster fashion, to generate a video signal representing the intensity of radiation prevailing at successively scanned locations. A selection circuit (6) contains a programmable memory which generates addresses suitable for selecting discrete sets (S) of neighbouring locations and a circuit (7) is responsive to the addresses to access to a processing circuit (8) only those portions of the video signal which correspond to the sets (S) of locations. The processing circuit (8) generates difference signals representing differences of intensity between neighbouring locations and evaluates the number (P.sub.tm) of difference signals exceeding each of a number of preset threshold values (t.sub.m) to generate a histogram. The numbers constituting the histogram are then weighted and scanned to generate a control signal (F) representing the focus.