Isochromatic demodulation by fringe scanning

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Authors: Grewal, G.S., Dubey, V.N. and Claremont, D.

http://www.blackwell-synergy.com/doi/abs/10.1111/j.1475-1305.2006.00290.x

Journal: Strain

Volume: 42

Pages: 273-281

ISSN: 0039-2103

DOI: 10.1111/j.1475-1305.2006.00290.x

RGB calibration is the fastest isochromatic demodulation technique, as it does not require unwrapping as in the case of phase-shifting method. The technique is based on constructing a look up table (LUT) of fringe order against RGB triplet from digital images and decoding the test image from the LUT. Research has shown that the technique, though very fast, is limited to fringe orders up to three with the conventional white light. The colours tend to merge beyond that and make it difficult to obtain a unique value of RGB triplet. Changes in fringe gradient caused by stretching/bunching of fringes in test model further add to errors. Special light sources with narrow-band spectral response are required with fringe tracking algorithms to demodulate higher fringe orders. The calibration technique is also sensitive to geometric and chromatic variations. This paper presents a cost-effective alternative solution to conventional RGB technique using a flatbed scanner. The system is capable of demodulating higher fringe order and incorporates information from other colour spaces. It does not require separate light sources and cameras, and is found to be insensitive to geometric and chromatic variations. Curve fitting technique has been proposed to determine accurate fringe orders.

This data was imported from Scopus:

Authors: Grewal, G.S., Dubey, V.N. and Claremont, D.J.

Journal: Strain

Volume: 42

Issue: 4

Pages: 273-281

eISSN: 1475-1305

ISSN: 0039-2103

DOI: 10.1111/j.1475-1305.2006.00290.x

RGB calibration is the fastest isochromatic demodulation technique, as it does not require unwrapping as in the case of phase-shifting method. The technique is based on constructing a look up table (LUT) of fringe order against RGB triplet from digital images and decoding the test image from the LUT. Research has shown that the technique, though very fast, is limited to fringe orders up to three with the conventional white light. The colours tend to merge beyond that and make it difficult to obtain a unique value of RGB triplet. Changes in fringe gradient caused by stretching/bunching of fringes in test model further add to errors. Special light sources with narrow-band spectral response are required with fringe tracking algorithms to demodulate higher fringe orders. The calibration technique is also sensitive to geometric and chromatic variations. This paper presents a cost-effective alternative solution to conventional RGB technique using a flatbed scanner. The system is capable of demodulating higher fringe order and incorporates information from other colour spaces. It does not require separate light sources and cameras, and is found to be insensitive to geometric and chromatic variations. Curve fitting technique has been proposed to determine accurate fringe orders. © 2006 The Authors. Journal compilation 2006 Blackwell Publishing Ltd.

This data was imported from Web of Science (Lite):

Authors: Grewal, G.S., Dubey, V.N. and Claremont, D.J.

Journal: STRAIN

Volume: 42

Issue: 4

Pages: 273-281

ISSN: 0039-2103

DOI: 10.1111/j.1475-1305.2006.00290.x

The data on this page was last updated at 04:43 on November 23, 2017.