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:
Jul. 11, 2000
Filed:
Mar. 25, 1997
Hirofumi Suda, Kanagawa-ken, JP;
Masamichi Toyama, Kanagawa-ken, JP;
Akihiro Fujiwara, Kanagawa-ken, JP;
Kunihiko Yamada, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An automatic focusing device for automatically controlling the focused state of an optical system on the basis of a video signal obtained within a focus detecting area which is set on an image sensing plane comprises: a tracing area setting circuit arranged to movably set, within said image sensing plane, an inner tracing area and an outer tracing area which surrounds the inner tracing area; a computing circuit arranged to compute information on a difference in a given frequency component of the video signal obtained from the inner and outer tracing areas in each of their different positions to which they are moved within the image sensing plane; determining means for determining the position or size of an object's image formed within the image sensing plane from the difference information computed by the computing circuit; and a circuit which is arranged to shift the focus detecting area to the position of the object's image determined by the determining circuit and to change the size of the focus detecting area according to the size of the object's image.