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Proceedings Paper

Influence of unresolved speckles in interferometric phase measurements
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Paper Abstract

The influence of unresolved speckles on the pixelwise modulation in phase shifting techniques has been investigated in recent publications by several authors. It has been shown that the number of points with sufficient modulation does not automatically decrease when unresolved speckles are used. However, the effect of unresolved speckles on the resulting phase map has not been examined. In this paper it is investigated how the averaging of speckles over the area of a pixel affects the validity of the phase resulting from phase shifting techniques. Special attention is given to the effect of unresolved speckles on phase singularities, since interferometric measurements with fully resolved speckles result in a phase map which contains a large number of phase singularities. Phase singularities are points where no phase value is defined, so that the appearance of singularities decreases the lateral resolution of the measurement. Additionally these points and their direct neighbourhood are a source of trouble for unwrapping algorithms. It is investigated how a slightly averaging of speckles alters the appearance of these problematic regions.

Paper Details

Date Published: 7 March 2006
PDF: 9 pages
Proc. SPIE 4101, Laser Interferometry X: Techniques and Analysis, (7 March 2006); doi: 10.1117/12.498433
Show Author Affiliations
Ervin Kolenovic, Bremer Institut fuer angewandte Strahltechnik (Germany)
Wolfgang Osten, Bremer Institut fuer angewandte Strahltechnik (Germany)
Werner P. O. Jueptner, Bremer Institut fuer angewandte Strahltechnik (Germany)


Published in SPIE Proceedings Vol. 4101:
Laser Interferometry X: Techniques and Analysis
Gordon M. Brown; Malgorzata Kujawinska; Werner P. O. Jueptner; Ryszard J. Pryputniewicz; Ryszard J. Pryputniewicz; Mitsuo Takeda, Editor(s)

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