Abstract
Digital shearography [1] is a practical inspection tool for industrial applications. Traditionally, the output of shearography is in the form of shearogram depicting the phase change caused by deformation. To determine the phase change quantitatively, it is necessary to capture at least three shearograms with different values of phase-shift at each deformed state. This phase-shifting techniqueworks well for static deformation measurement, but it is unsuitable for measuring dynamic deformation. Therefore, phase demodulation from a single shearogram is of great interest in practical applications. Previous work by other researchers has demonstrated that the Fourier transform (FT) method [2]and the spiral phase transform (SPT) method [3-4] can be used to extract the phase map from a single fringe pattern. However, the FT method requires that a large spatial carrier frequency should present in the fringe pattern. The reported SPT method estimates the fringe orientation from intensity derivatives, which will cause errors when there are more than two extremes in the phase map. However, the phase of a shearogram usually has two or more extremes in digital shearography. To deal with this problem, in this paper we describe a new procedure to extract phase from shearogram. We calculate the fringe orientation by optical flow from two successive shearograms and then determine the phase of the shearogram by spiral phase transform. We describe the principle of the method and then demonstrate it through both simulation and experimental results.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Francis, D., Tatam, R.P., Groves, R.M.: Shearography technology and applications: a review. Meas. Sci. Technol. 21, 102001 (2010)
Takeda, M., Ina, H., Kobayashi, S.: Fourier-transform method of fringe pattern analysis for computer-based topography and interferometry. J. Opt. Soc. Am. 72, 156–159 (1982)
Kieran, G.L., Donald, J.B., Michael, A.O.: Natural demodulation of two-dimensional fringe patterns. I. General background of the spiral phase quadrature transform. J. Opt. Soc. Am. A 18, 1862–1870 (2001)
Kieran, G.L.: Natural demodulation of two-dimensional fringe patterns. II. Stationary phase analysis of the spiral phase quadrature transform. J. Opt. Soc. Am. A 18, 871–1881 (2001)
Horn, B.K.P., Schunck, B.G.: Determining optical flow. Artificial Intelligence 17, 185–203 (1981)
Vargas, J., Antonio, Q.J., Sorzano, C.O.S., Estrada, J.C., Carazo, J.M.: Two-step interferometry by a regularized optical flow algorithm. Opt. Lett. 36, 3485–3487 (2011)
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2014 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Xu, J., Gao, J. (2014). Phase Extraction by Spiral Phase Transform in Digital Shearography. In: Osten, W. (eds) Fringe 2013. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-36359-7_31
Download citation
DOI: https://doi.org/10.1007/978-3-642-36359-7_31
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-36358-0
Online ISBN: 978-3-642-36359-7
eBook Packages: EngineeringEngineering (R0)