Comparative measurement by phase-shifting digital speckle interferometry using holographically generated reference wave

Moustafa, Nasser A.; Kornis, J.; Füzessy, Z.

doi:10.1117/1.602171

Cited by 11 publications

(5 citation statements)

References 9 publications

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“…Various possible transforms have been published recently: (1) mean-absolute speckle-intensity variation, 23 (2) a method based on contrast difference, 24 and (3) phase shifting by using three, 25 four, 26 or five 27 consecutive images. A thousand speckle images of size 1 × 102 pixels are acquired per second.…”

Section: Speckle Image Preprocessingmentioning

confidence: 99%

Cost-efficient speckle interferometry with plastic optical fiber for unobtrusive monitoring of human vital signs

Podbreznik

Đonlagić

Lešnik³

et al. 2013

J. Biomed. Opt

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A cost-efficient plastic optical fiber (POF) system for unobtrusive monitoring of human vital signs is presented. The system is based on speckle interferometry. A laser diode is butt-coupled to the POF whose exit face projects speckle patterns onto a linear optical sensor array. Sequences of acquired speckle images are transformed into one-dimensional signals by using the phase-shifting method. The signals are analyzed by band-pass filtering and a Morlet-wavelet-based multiresolutional approach for the detection of cardiac and respiratory activities, respectively. The system is tested with 10 healthy nonhospitalized persons, lying supine on a mattress with the embedded POF. Experimental results are assessed statistically: precisions of 98.8% ± 1.5% and 97.9% ± 2.3%, sensitivities of 99.4% ± 0.6% and 95.3% ± 3%, and mean delays between interferometric detections and corresponding referential signals of 116.6 ± 55.5 and 1299.2 ± 437.3 ms for the heartbeat and respiration are obtained, respectively.

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Section: Speckle Image Preprocessingmentioning

confidence: 99%

Cost-efficient speckle interferometry with plastic optical fiber for unobtrusive monitoring of human vital signs

Podbreznik

Đonlagić

Lešnik³

et al. 2013

J. Biomed. Opt

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“…One natural way for the extension of the upper measuring range can be the application of compensation methods 1,2 . Because digital holographic interferometry and TV holography operate with images recorded with a digital camera, several computer based compensation method can be applied [3][4][5] .…”

Section: Introductionmentioning

confidence: 99%

Extension of the measuring range in deformation measurement using artificial phase compensation

Kornis

Séfel

2012

SPIE Proceedings

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Compensation or comparative measurement is a natural way to overcome the limited measuring range of TV holography or digital holography. In this case the resultant displacement field is the difference of the actual deformation and a known deformation pattern. The compensation can be digital, because these measuring techniques operate with images recorded with digital camera.Development of Spatial Light Modulators (SLM) enables the application of active holographic optical elements in coherent optical metrology. These modulators are capable to reconstruct digital holograms optically; therefore they can be used as active holographic optical elements. The goal of the project was to perform adaptive comparative measurements, where an optically reconstructed image of a recorded or simulated single or double exposure hologram is used for holographic illumination of another object.In this paper conventional TV holographic or digital holographic arrangement with holographic object illumination applied for comparative displacement measurement with adaptive features. Measurement setups were built, containing devices performing feedback, which is capable to project the real image of the master object -using its previously recorded or computer simulated digital holograms -onto the test object to calculate the difference deformation directly.

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“…In ESPI comparative measurement is possible if two objects are present in the two arms of the interferometer at the same time 3,4 or if a single or double exposure hologram is made of one of the objects and used for holographic illumination of the other one. [5][6][7] This illumination can be performed using digital holograms, due to the recent development of spatial light modulators (SLM), which makes the optical reconstruction of digital holograms possible. 8 This approach is a straightforward digital implementation of the analogue comparative measuring technique, where regular hologram plates are used to store and reconstruct optical wavefronts.…”

Section: Introductionmentioning

confidence: 99%

Comparative electronic speckle pattern interferometry using adaptive holographic illumination

2011

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The development of spatial light modulators enables the application of active holographic optical elements in electronic speckle pattern interferometry. In our work adaptive comparative measurement is done, where an optically reconstructed image of a recorded or simulated single or double exposure hologram is used for holographic illumination of another object. In this paper, we present experimental results of measuring the difference of two deformations using this technique. The displacement difference can also be obtained numerically, if the wavefront used as a coherent illuminating mask does not belong to an existing object. This type of interferometer can easily adapt to the change of measuring conditions. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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Comparative measurement by phase-shifting digital speckle interferometry using holographically generated reference wave

Cited by 11 publications

References 9 publications

Cost-efficient speckle interferometry with plastic optical fiber for unobtrusive monitoring of human vital signs

Cost-efficient speckle interferometry with plastic optical fiber for unobtrusive monitoring of human vital signs

Extension of the measuring range in deformation measurement using artificial phase compensation

Comparative electronic speckle pattern interferometry using adaptive holographic illumination

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