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:
Apr. 15, 1997
Filed:
Jul. 29, 1994
Matsushita Electric Industrial Co., Ltd., Osaka-fu, JP;
Abstract
A focus position detecting method includes: obtaining quantized two-dimensional image data including an object to be in focus with respect to an optical system by imaging the object through the optical system, defining a specified area in the two-dimensional image data; defining a partial image in the specified area, the partial image being composed of a target pixel and peripheral pixels on a line in a specified direction in which the target pixel exists; defining a left area and a right area respectively positioned on left and right sides of the target pixel on the line in the specified direction; calculating gray-level data of each pixel in the left area; calculating gray-level data of each pixel in the right area; obtaining as a gray-level ratio a ratio of calculation result of the left area to calculation result of the right area; calculating an evaluation function by means of the gray-level ratio by repeating the gray-level ratio calculating step in the specified area; obtaining a plurality of evaluation function calculation values in a variety of optical positions by repeating the steps for calculating the gray-level data of the left and right areas, obtaining the gray-level ratio, and calculating the evaluation function through variation of the optical position of the object, and obtaining a focus position of the object with respect to the optical system based on the evaluation function calculation values.