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:
Dec. 02, 1997
Filed:
Aug. 05, 1996
Shigeo Toji, Tokyo, JP;
Fuji Photo Film Co., Ltd., Kanagawa, JP;
Abstract
A zone for measuring distance is enlarged by adding an area where a contrast ratio is relatively high in the case of the photographing against the light. Thus, the sensitivity for judging a contrast ratio is increased and improper focusing is prevented. The brightness when an evaluative value is a maximum and the brightness at a moment when the evaluative value is not at maximum, for example when it is at a minimum, are compared. If the difference of brightness becomes too large, the maximum evaluative value is ignored and the detection is repeated. The determination of when the difference in brightness is too large is made to be dependent on parameters such as gain of the AGC circuit, gain of the amplifier and iris opening which affect the noise in the evaluative value so as to more accurately judge when the when the maximum evaluative value should be ignored.