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Proceedings Paper

Optical Three-Dimensional Displacement Meter
Author(s): Eiji Ogita; Toshitsugu Ueda; Daisuke Yamazaki
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Paper Abstract

We have developed a displacement meter which simultaneously measures the (distance and direction of) movement of an object in three dimensions. A piece of retroreflective "Scotchlite" adhesive tape, with a grid printed on it, is attached to the object (target) and illuminated by a single laser beam. The displacements in the X-Y plane perpendicular to the beam are determined by measuring the movement of the grid images appearing at the X and Y detectors. (The reflected beam is split, and transmitted to X, Y and Z detectors). The displacement along the Z axis parallel to the beam is determined -- using a Michelson interferometer -- from the movement of interference fringes which occur when the light reflected from the target is superimposed on a direct "reference" beam from the laser. A new high speed image sensor is used for X, Y and Z detectors to measure the movement of the grid image and the interference pattern -- as a result, the meter has a frequency response from DC to 20 kHz. The sensor is a high resolution spatial filter (array of photocells connected or scanned in such a manner as to be sensitive to a particular light pattern on the array). Using a spatial filter eliminates the need for correlation or other complex signal processing. The accuracy is of the order of 20 μm for X and Y axes and 1.5 μm for the Z axis. The optical system (lenses, mirrors and sensors) is compact, so the meter is portable.

Paper Details

Date Published: 25 November 1985
PDF: 7 pages
Proc. SPIE 0556, Intl Conf on Speckle, (25 November 1985); doi: 10.1117/12.949533
Show Author Affiliations
Eiji Ogita, Yokogawa Hokushin Electric Corp. (Japan)
Toshitsugu Ueda, Yokogawa Hokushin Electric Corp. (Japan)
Daisuke Yamazaki, Yokogawa Hokushin Electric Corp. (Japan)

Published in SPIE Proceedings Vol. 0556:
Intl Conf on Speckle
Henri H. Arsenault, Editor(s)

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