Title:
OPTICAL SENSOR FOR DISTANCE MEASUREMENT
Document Type and Number:
WIPO Patent Application WO2002097367
Kind Code:
A3
Abstract:
Apparatus and method are provided for distance measurement to a remote surface using high frequency modulated transmitted and reflected laser beams and phase-shift calculations. To improve phase-shift resolution, the reflected bean is further modulated, before detection, at a high frequency similar yet different from that of the transmitted beam so as create a resulting detector signal having at least a lower frequency signal which is easily detected by a response limited detector. The lower frequency signal retains the phase-shift information and thus enables determination of the phase-shift information with stable, inexpensive low-frequency optical detectors. Three-dimensional mapping can performed wherein one or more apparatus employ a plurality of detectors or a scanner producing a plurality of sequential reflected beams, each of which results in a plurality of phase-shift information for an area on the surface.
Inventors:
BARKER ANDREW J
Application Number:
PCT/CA2002/000795
Publication Date:
July 10, 2003
Filing Date:
May 29, 2002
Export Citation:
Assignee:
EAGLE RAY CORP (CA)
International Classes:
G01C3/06; G01S7/481; G01S7/4915; G01S7/493; G01S17/36; (IPC1-7): G01S7/481; G01S7/35
Foreign References:
| US5082364A | 1992-01-21 | |||
| US5737085A | 1998-04-07 | |||
| US6100540A | 2000-08-08 |
Other References:
PATENT ABSTRACTS OF JAPAN vol. 018, no. 412 (P - 1780) 2 August 1994 (1994-08-02)
PATENT ABSTRACTS OF JAPAN vol. 1997, no. 06 30 June 1997 (1997-06-30)
PATENT ABSTRACTS OF JAPAN vol. 1997, no. 06 30 June 1997 (1997-06-30)
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