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Proceedings Paper

Three-dimensional shape measurement using images reconstructed by the computer from a hologram
Author(s): Yoshinori Kajiki; Hiroaki Ueda; Kenji Taima; Hideki Okamoto; Eiji Shimizu
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Paper Abstract

Laser holographic interferometry has been developed to provide a direct optical transonic flow diagnostic tool. It is often convenient, due to the needs of passage instrumentation and blade fixtures, to restrict optical access to one side of the test facility. To overcome this limitation a reflective holographic system has been devised which uses one of the internal tunnel walls as a mirror surface. However, due to the movement of the facility, spurious rigid body vibration information is added to the transonic flow data. A numerical method has been developed by Warwick University and demonstrated on the Laval nozzle flow facility at EPFL which uses a digital fast Fourier transform algorithm to remove the superimposed background information. A further method known as phase unwrapping is used to extract quantitative numerical data from the interferometrically formed images automatically. A complication to the experiment was created by the non-linear deflection of glass window between the two holographic exposures. The deflection was determined experimentally to be of a parabolic nature and has been successfully removed. This was achieved by post processing the unwrapped fringe data.

Paper Details

Date Published: 1 May 1994
PDF: 11 pages
Proc. SPIE 2176, Practical Holography VIII, (1 May 1994); doi: 10.1117/12.172643
Show Author Affiliations
Yoshinori Kajiki, Koshien Univ. (Japan)
Hiroaki Ueda, Labs. of Image Information Science and Technology (Japan)
Kenji Taima, Labs. of Image Information Science and Technology (Japan)
Hideki Okamoto, Labs. of Image Information Science and Technology (Japan)
Eiji Shimizu, Osaka City Univ. (Japan)

Published in SPIE Proceedings Vol. 2176:
Practical Holography VIII
Stephen A. Benton, Editor(s)

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