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Optical Engineering

Application of acousto-optic cells and video processing to achieve signal-to-noise improvements in variable resolution moiré profilometry
Author(s): Joel H. Blatt; Jeffery A. Hooker; Huey C. Ho; Eddie H. Young
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Paper Abstract

Moiré techniques can be a powerful tool to determine surface shape or deviation of a shape in progress from a final or desired shape. The presence of the high-contrast viewing grating and the distorted grating in the final image plane makes the moiré pattern hard to see. Moving grating techniques have been developed to improve the visibility of the moiré pattern, but at the expense of complex moving parts. Several variable resolution projection moiré techniques have been developed that either move the grating or eliminate its presence electronically, and have neither mechanical moving parts nor any physical gratings. One system uses an acousto-optics cell to generate, project, and move the gratings, while the moiré is viewed through a second synchronized A-O cell. The second system uses an interferometer to generate and project variable spacing gratings that are made to move across the target and across a reference surface by an A-O beam deflector. Video processing of the reference image generates the transmissive filter that produces the moiré pattern. A third system removes the grating presence electronically but retains high-contrast moiré contours. Noise reduction is shown in a series of moiré images of targets.

Paper Details

Date Published: 1 October 1992
PDF: 10 pages
Opt. Eng. 31(10) doi: 10.1117/12.58878
Published in: Optical Engineering Volume 31, Issue 10
Show Author Affiliations
Joel H. Blatt, Florida Institute of Technology (United States)
Jeffery A. Hooker, Florida Institute of Technology (United States)
Huey C. Ho, NEOS Technology, Inc. (United States)
Eddie H. Young, NEOS Technologies, Inc. (United States)

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