Application of semiconductor laser range finder to position control of lens in auto-focus camera

Author

Yoshida, Yoshiji ; Shinohara, Shigenobu ; Ikeda, Hiroaki ; Tada, Ken-Ichi ; Yoshida, Hirofumi ; Nishide, Ken-ichi ; Sumi, Masao

Author_Institution

Shizuoka Univ., Hamamatsu, Japan

fYear

1991

fDate

28 Oct-1 Nov 1991

Firstpage

2357

Abstract

It is proposed to use an infrared semiconductor laser rangefinder to get a just-focusing signal, for the auto-focus (AF) system of a camera. Using both a measured distance to a moving object and its speed, the lens position of a single-lens reflex (SLR) camera is controlled. The range measurement error when installed in the AF system of an SLR camera is within 1% in a range of 0.3 m to 0.6 m. The error of 1% is below the normalized depth of field of 1.5-4.0% of the camera lens, which is consistent with the fact that some clear photographs are obtained from a moving object

Keywords

cameras; distance measurement; lenses; measurement by laser beam; position control; semiconductor lasers; auto-focus camera; just-focusing signal; lens position; measured distance; normalized depth; position control; range measurement error; semiconductor laser range finder; single-lens reflex; speed; Cameras; Laser applications; Lenses; Optical control; Position control; Position measurement; Power measurement; Pulse modulation; Semiconductor lasers; Velocity measurement;

fLanguage

English

Publisher

ieee

Conference_Titel

Industrial Electronics, Control and Instrumentation, 1991. Proceedings. IECON '91., 1991 International Conference on

Conference_Location

Kobe

Print_ISBN

0-87942-688-8

Type

conf

DOI

10.1109/IECON.1991.238976

Filename

238976