A Comparison of Electronic Heterodyne Moire Deflectometry and Electronic Heterodyne Holographic Interferometry for Flow Measurements

851896

10/01/1985

Event
Aerospace Technology Conference and Exposition
Authors Abstract
Content
Electronic heterodyne moire deflectometry and electronic heterodyne holographic interferometry are compared as methods for the accurate measurement of refractive index and density change distributions of phase objects. Experimental results are presented to show that the two methods have comparable accuracy for measuring the first derivative of the interferometric fringe shift. The phase object for the measurements is a large crystal of KD*P, whose refractive index distribution can be changed accurately and repeatably for the comparison. Although the refractive index change causes only about one interferometric fringe shift over the entire crystal, the derivative shows considerable detail for the comparison. As electronic phase measurement methods, both methods are very accurate and are intrinsically compatible with computer controlled readout and data processing. Heterodyne moire is relatively inexpensive and has high variable sensitivity. Heterodyne holographic interferometry is better developed, and can be used with poor quality optical access to the experiment.
Meta TagsDetails
DOI
https://doi.org/10.4271/851896
Pages
16
Citation
Decker, A., and Stricker, J., "A Comparison of Electronic Heterodyne Moire Deflectometry and Electronic Heterodyne Holographic Interferometry for Flow Measurements," SAE Technical Paper 851896, 1985, https://doi.org/10.4271/851896.
Additional Details
Publisher
Published
Oct 1, 1985
Product Code
851896
Content Type
Technical Paper
Language
English