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Proceedings Paper

Study Of Combustion Phenomena By Combined Deflexion Mapping And Speckle Superposition Techniques
Author(s): German Da Costa
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Paper Abstract

One of the more widely used methods for the study of combustion phenomena is the deflexion-mapping method, in combination with Moire techniques. As combustion phenomena are essentially dynamic, multiple frames are generally needed to record the whole event. An exact superposition of each pair of frames may then be done, in order to deduce from the resulting Moire patterns, the change of the thermodynamic variables in the corresponding time interval. We present here a new technique by means of which the superposition of the pairs of frames can be done exactly. This superposition is obtained by comparing a reference speckle pattern registered in each frame with a standard. The reference speckle pattern is provided by an immobile auxiliary diffuser. After developing, a laser beam is directed through the reference region of the nearly superposed pairs of frames, and these are displaced one respect to the other until Young fringes disappear. This yields the criterion of correct superposition. A major advantage of this technique is that the filtering of the Moire patterns corresponding to each pair of frames, and the control of their correct superposition, are made simultaneously on the focal plane of a single lens in a simple optical setup.

Paper Details

Date Published: 14 September 1977
PDF: 7 pages
Proc. SPIE 0097, 12th Intl Congress on High Speed Photography, (14 September 1977); doi: 10.1117/12.955249
Show Author Affiliations
German Da Costa, Universidad SimOn Bolivar, (Venezuela)

Published in SPIE Proceedings Vol. 0097:
12th Intl Congress on High Speed Photography
Martin C. Richardson, Editor(s)

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