Removing Quasi-Periodic Noise in Strain Maps by Filtering in the Fourier Domain
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Quasi-periodic noise due to various reasons often corrupts strainmaps obtained with full-field measuring systems. The aim of this didactic paper is to show how to remove this noise by changing some Fourier coefficients involved in the two-dimensional (2D) Fourier transform of these strain maps. The basics of the 2D Fourier transform of images, which is a common tool in image processing but that is only scarcely employed in the experimental mechanics community, are first briefly recalled. Several procedures employed for removing undesirable frequencies in strain maps are then discussed. Three different examples illustrate the benefit of this approach.
KeywordsFourier Transform Grid Method Image Processing Strain Measurement Strain Map Restoration
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- 1.Grédiac, M., and Hild, F. (eds), Full-Field Measurements and Identification in Solid Mechanics, Wiley, p. 496, (2012). ISBN: 9781848212947.Google Scholar
- 4.Sutton, M.A., Orteu, J.-J., and Schreier, H.W., Image Correlation for Shape, Motion and Deformation Measurements—Basic Concepts, Theory and Applications, Springer, New York (2009).Google Scholar
- 6.Avril, S., Feissel, P., Pierron, F., and Villon, P., “Estimation of the Strain Field from Full-Field Displacement Noisy Data,” European Journal of Computational Mechanics 17(5–7): 857–868 (2008).Google Scholar
- 13.Gonzalez, R.C., and Woods, R.E., Digital Image Processing, 3rd Edition, Prentice Hall, Upper Saddle River, NJ (2008).Google Scholar
- 14.The MathWorks Inc., MATLAB. version 8.3 (R2014a), The MathWorks Inc., (2014).Google Scholar
- 15.Gonzalez, R.C., Woods, R.E., and Eddins, S.L., Digital Image Processing Using MATLAB, 2nd Edition, Gatesmark Publishing, Knoxville, TN (2009).Google Scholar
- 16.Kaur, S., and Singh, R., “An Efficient Method for Periodic Vertical Banding Noise Removal in Satellite Images,” International Journal of Computer Science and Engineering 4(10): 1710–1721 (2012).Google Scholar
- 17.Wang, J., and Liu, D.C., “2D FFT Periodic Noise Removal on Strain Images,” Proceedings of the 4th International Conference on Bioinformatics and Biomedical Engineering (iCBBE), Chengdu, China, pp 1–4, (2010).Google Scholar
- 19.Grédiac, M., and Sur, F., “Effect of Sensor Noise on the Resolution and Spatial Resolution of the Displacement and Strain Maps Obtained with the Grid Method,” Strain 50(1): 1–27 (2014). Paper invited for the 50th anniversary of the journal.Google Scholar