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. 03, 1987
Filed:
Aug. 26, 1985
Tokuichi Tsunekawa, Kanagawa, JP;
Kazuya Hosoe, Tokyo, JP;
Takao Kinoshita, Tokyo, JP;
Takashi Kawabata, Kanagawa, JP;
Shinji Sakai, Tokyo, JP;
Tatsuya Taguchi, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Disclosed is a method of detecting the focusing condition of an image forming optical system to an object, in which two images of the object are formed with respective light beams from the prescribed exit pupil areas lying in almost symmetry to each other with respect to the optical axis of the optical system and are sensed to obtain an equal number of picture element data for each of the images, and based on the thus-obtained picture element data, while sequential shifting for the first image is carried out from its one end to its opposite end, and a sequential shifting for the second image from its symmetric one end thereto to its opposite end, each by a predetermined number of picture elements, a correlation betweeen the first and second images in every predetermined equal number of picture elements is sought, whereby an optimum correlation is obtained, the corresponding mutual positional relationship between the above-described predetermined numbers of picture elements is detected to discriminate whether or not the above-described image forming optical system is in focus for the above-described object.