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:
Jun. 17, 1997
Filed:
Jun. 30, 1995
Shigeyuki Uchiyama, Tokyo, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A defocus amount is accurately determined within the photo field. As applied to a focus state detection device, DC reduction filter process data is computed without completely extracting the DC component of the signal string output from an image sensor. The DC reduction filter process data is divided into three regions, and a determination is made as to whether focus state detection is possible for each region. When the determination is negative, a determination is made as to whether focus state detection is possible for all regions of first filter process data that extracts high frequency components. When the determination is negative, a determination is made in a similar manner as to whether focus state detection is possible on the basis of second filter process data and third filter process data. When the determination has been made that focus state detection is possible for all regions with one of the filter process data, a standard block is set, a weighing coefficient is set for each block on the basis of this standard block, the defocus amount of each block is altered, the defocus amounts are combined, and a final defocus amount is determined.