Title :
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
fDate :
28 Oct-1 Nov 1991
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;
Conference_Titel :
Industrial Electronics, Control and Instrumentation, 1991. Proceedings. IECON '91., 1991 International Conference on
Conference_Location :
Kobe
Print_ISBN :
0-87942-688-8
DOI :
10.1109/IECON.1991.238976
