Focus detecting and/or focus adjustment method
US4647174A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1985 |
| Grant date | Mar 3, 1987 |
| Priority date | — |
| Expiry date | Aug 26, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/346
- WIPO fieldOptics
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.