OPTICAL SENSOR FOR DISTANCE MEASUREMENT

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...

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Bibliographic Details
Main Author BARKER, ANDREW, J
Format Patent
LanguageEnglish
French
German
Published 07.04.2004
Edition7
Subjects
ANALOGOUS ARRANGEMENTS USING OTHER WAVES
DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES
GYROSCOPIC INSTRUMENTS
LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION ORRERADIATION OF RADIO WAVES
MEASURING
MEASURING DISTANCES, LEVELS OR BEARINGS
NAVIGATION
PHOTOGRAMMETRY OR VIDEOGRAMMETRY
PHYSICS
RADIO DIRECTION-FINDING
RADIO NAVIGATION
SURVEYING
TESTING
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Summary: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.
Bibliography:Application Number: EP20020729731