20 August 2015 Use of specklegrams background terms for speckle photography combined with phase-shifting electronic speckle pattern interferometry
Redouane Zemmamouche, Jean-François Vandenrijt, Aïcha Medjahed, Ivan de Oliveira, Marc P. Georges
Author Affiliations +
Abstract
Electronic speckle pattern interferometry (ESPI) is combined with digital speckle photography (DSP) to measure out-of-plane deformation in the presence of large in-plane translation or rotation. ESPI is used to measure out-of-plane displacements smaller than the speckle diameter. In-plane displacements larger than the speckle size are obtained by DSP using artifacts images computed from the phase-stepped specklegrams. Previous works use the specklegram modulation for that purpose, but we show that this can lead to errors in the case of low modulation. In order to avoid this, a simple averaging of phase-stepped specklegrams allows obtaining the average irradiance, which contains information on the speckled object image. The latter can be used more efficiently than the modulation in DSP and is simpler to compute. We also perform a numerical simulation of specklegrams, which show that the use of background terms is much more stable against some error sources as compared to modulation. We show experimental evidence of this in various experiments combining out-of-plane ESPI measurements with in-plane translations or rotations obtained by our DSP method. The latter has been used efficiently to restore phase loss in out-of-plane ESPI measurements due to large in-plane displacements.
© 2015 Society of Photo-Optical Instrumentation Engineers (SPIE) 0091-3286/2015/$25.00 © 2015 SPIE
Redouane Zemmamouche, Jean-François Vandenrijt, Aïcha Medjahed, Ivan de Oliveira, and Marc P. Georges "Use of specklegrams background terms for speckle photography combined with phase-shifting electronic speckle pattern interferometry," Optical Engineering 54(8), 084110 (20 August 2015). https://doi.org/10.1117/1.OE.54.8.084110
Published: 20 August 2015
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CITATIONS
Cited by 11 scholarly publications.
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KEYWORDS
Digital signal processing

Speckle

Modulation

Phase shift keying

Photography

Phase shifts

Digital photography

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