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Proceedings Paper

OPTOTRAK: at last a system with resolution of 10 um
Author(s): David Gardner Crouch; L. Kehl; J. R. Krist
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Paper Abstract

Northern Digital's first active marker point measurement system, the WATSMART, was begun in 1983. Development ended in 1985 with the manufacture of a highly accurate system, which achieved .15 to .25 mm accuracies in three dimensions within a .75-meter cube. Further improvements in accuracy were rendered meaningless, and a great obstacle to usability was presented by a surplus light problem somewhat incorrectly known as "the reflection problem". In 1985, development of a new system to overcome "the reflection problem" was begun. The advantages and disadvantages involved in the use of active versus passive markers were considered. The implications of using a CCD device as the imaging element in a precision measurement device were analyzed, as were device characteristics such as dynamic range, peak readout noise and charge transfer efficiency. A new type of lens was also designed The end result, in 1988, was the first OPTOTRAK system. This system produces three-dimensional data in real-time and is not at all affected by reflections. Accuracies of 30 microns have been achieved in a 1-meter volume. Each two-dimensional camera actually has two separate, one-dimensional, CCD elements and two separate anamorphic lenses. It can locate a point from 1-8 meters away with a resolution of 1 part in 64,000 and an accuracy of 1 part in 20,000 over the field of view.

Paper Details

Date Published: 1 August 1990
PDF: 1 pages
Proc. SPIE 1356, Image-Based Motion Measurement, (1 August 1990); doi: 10.1117/12.23892
Show Author Affiliations
David Gardner Crouch, Northern Digital, Inc. (Canada)
L. Kehl, Northern Digital, Inc. (Canada)
J. R. Krist, Northern Digital, Inc. (Canada)

Published in SPIE Proceedings Vol. 1356:
Image-Based Motion Measurement
James S. Walton, Editor(s)

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