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Proceedings Paper

Quantitative holographic interferometry applied to combustion and compressible flow research
Author(s): Peter John Bryanston-Cross; D. P. Towers
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Paper Abstract

The application of holographic interferometry to phase object analysis is described. Emphasis has been given to a method of extracting quantitative information automatically from the interferometric fringe data. To achieve this a carrier frequency has been added to the holographic data. This has made it possible, firstly to form a phase map using a fast Fourier transform (FFT) algorithm. Then to `solve,' or unwrap, this image to give a contiguous density map using a minimum weight spanning tree (MST) noise immune algorithm, known as fringe analysis (FRAN). Applications of this work to a burner flame and a compressible flow are presented. In both cases the spatial frequency of the fringes exceed the resolvable limit of conventional digital framestores. Therefore, a flatbed scanner with a resolution of 3200 X 2400 pixels has been used to produce very high resolution digital images from photographs. This approach has allowed the processing of data despite the presence of caustics, generated by strong thermal gradients at the edge of the combustion field. A similar example is presented from the analysis of a compressible transonic flow in the shock wave and trailing edge regions.

Paper Details

Date Published: 2 March 1993
PDF: 14 pages
Proc. SPIE 1732, Holographics International '92, (2 March 1993); doi: 10.1117/12.140441
Show Author Affiliations
Peter John Bryanston-Cross, Warwick Univ. (United Kingdom)
D. P. Towers, Eidgenossische Technisce Hochscule (Switzerland)


Published in SPIE Proceedings Vol. 1732:
Holographics International '92

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