Title:
RANGE FINDER FOR PASSIVE TYPE AUTO-FOCUSING APPARATUS
Document Type and Number:
Japanese Patent JPH05107061
Kind Code:
A
Abstract:
PURPOSE:To prevent false measurement of a distance due to a fitting error and to enable quick and accurate measurement of the distance by adjusting a position of start of writing to a zero cross memory in accordance with each photosensor and by detecting two other amounts of slide in relation to a zero cross behavior signal being a reference. CONSTITUTION:After secondary differences of luminance distribution signals of the light from a subject which is caught by line sensors 10b, 20b and 30b are computed 12, 22 and 32, the respective zero cross points thereof are detected 13, 23 and 33 and waveform signals thereof are stored in zero cross memory circuits 14, 24 and 34 corresponding to addresses outputted from address computing circuits 15, 25 and 35 corresponding to positions of pixels. Since a deviation adjusting signal for setting the positions of pixels corresponding to the amount of correction generated according to a fitting error is inputted to the circuits 15, 25 and 35, false measurement of a distance due to the fitting error is prevented. Besides, the amounts of slide at the time when one zero cross point is used as reference zero cross data and two other ones are made to accord therewith are used as distance data, and the distance to the subject is determined.
Inventors:
ISHIGURO MINORU
Application Number:
JP29520791A
Publication Date:
April 27, 1993
Filing Date:
October 15, 1991
Export Citation:
Assignee:
FUJI PHOTO OPTICAL CO LTD
International Classes:
G01C3/06; G01B11/00; G02B7/30; (IPC1-7): G01C3/06; G02B7/30
Attorney, Agent or Firm:
Hideto Mochizuki
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