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:
Oct. 22, 1996
Filed:
Apr. 19, 1994
Fuji Photo Film Co., Ltd., Kanagawa, JP;
Abstract
A phase difference detection type rangefinder is provided which calculates a distance value of each subject of two or more subjects at different distances. The rangefinder has a correlation calculation unit for calculating a correlation factor between images of a same subject focussed on a base photosensor and a reference photosensor, a second order differentiation unit for calculating second order differential values of correlation factors calculated by the correlation calculation unit, a second order differential value comparison unit for selecting a maximum second order differential value from the second order differential values calculated by the second order differentiation unit, a three-point interpolation unit for calculating an interpolation value through three-point interpolation using the maximum second order differential value and two second order differential values having the phases before and after the phase of the maximum second order differential value, and a distance value calculation unit for calculating a distance value from the phase of the maximum second order differential value and the interpolation value.