MENNER, Philipp ;GERHARD, Henry ;BUSSE, Gerd . Lockin-Interferometry: Principle and Applications in NDE. Strojniški vestnik - Journal of Mechanical Engineering, [S.l.], v. 57, n.3, p. 183-191, june 2018. ISSN 0039-2480. Available at: <https://www.sv-jme.eu/article/lockin-interferometry-principle-and-applications-in-nde/>. Date accessed: 20 dec. 2024. doi:http://dx.doi.org/10.5545/sv-jme.2010.169.
Menner, P., Gerhard, H., & Busse, G. (2011). Lockin-Interferometry: Principle and Applications in NDE. Strojniški vestnik - Journal of Mechanical Engineering, 57(3), 183-191. doi:http://dx.doi.org/10.5545/sv-jme.2010.169
@article{sv-jmesv-jme.2010.169,
author = {Philipp Menner and Henry Gerhard and Gerd Busse},
title = {Lockin-Interferometry: Principle and Applications in NDE},
journal = {Strojniški vestnik - Journal of Mechanical Engineering},
volume = {57},
number = {3},
year = {2011},
keywords = {Lockin-ESPI; Lockin-Shearography; defect-selective imaging; interferometric depth profiling},
abstract = {Interferometry is relevant for non-destructive evaluation (NDE) since dimensional changes much smaller than an optical wavelength result in detectable signals. Fringe images obtained with Electronic-Speckle-Pattern-Interferometry (ESPI) or shearography display changes of surface topography between two states of an object, usually using a static load. Usually, hidden defects are found by comparing the observed fringe pattern to the one obtained on an intact reference component and to attribute observed differences to a defect. Our approach is a periodical object illumination with light that is absorbed in the surface to generate heat and a corresponding modulation of thermal expansion. At the same time fringe images are recorded (either with ESPI or shearography) to give a stack. Subsequently, each image is unwrapped and thereafter the time-dependent content of each pixel is Fourier transformed at the excitation frequency, so the result is local amplitude and phase of the modulated response at this frequency. The phase image displays local delay between excitation and response. This phase change depends on the depth where the defect is located since thermal waves are involved. In this paper, NDE-examples obtained using this new technique are presented. It is also shown how the achieved improvement as compared to conventional interferometry is up to an order of magnitude.},
issn = {0039-2480}, pages = {183-191}, doi = {10.5545/sv-jme.2010.169},
url = {https://www.sv-jme.eu/article/lockin-interferometry-principle-and-applications-in-nde/}
}
Menner, P.,Gerhard, H.,Busse, G. 2011 June 57. Lockin-Interferometry: Principle and Applications in NDE. Strojniški vestnik - Journal of Mechanical Engineering. [Online] 57:3
%A Menner, Philipp %A Gerhard, Henry %A Busse, Gerd %D 2011 %T Lockin-Interferometry: Principle and Applications in NDE %B 2011 %9 Lockin-ESPI; Lockin-Shearography; defect-selective imaging; interferometric depth profiling %! Lockin-Interferometry: Principle and Applications in NDE %K Lockin-ESPI; Lockin-Shearography; defect-selective imaging; interferometric depth profiling %X Interferometry is relevant for non-destructive evaluation (NDE) since dimensional changes much smaller than an optical wavelength result in detectable signals. Fringe images obtained with Electronic-Speckle-Pattern-Interferometry (ESPI) or shearography display changes of surface topography between two states of an object, usually using a static load. Usually, hidden defects are found by comparing the observed fringe pattern to the one obtained on an intact reference component and to attribute observed differences to a defect. Our approach is a periodical object illumination with light that is absorbed in the surface to generate heat and a corresponding modulation of thermal expansion. At the same time fringe images are recorded (either with ESPI or shearography) to give a stack. Subsequently, each image is unwrapped and thereafter the time-dependent content of each pixel is Fourier transformed at the excitation frequency, so the result is local amplitude and phase of the modulated response at this frequency. The phase image displays local delay between excitation and response. This phase change depends on the depth where the defect is located since thermal waves are involved. In this paper, NDE-examples obtained using this new technique are presented. It is also shown how the achieved improvement as compared to conventional interferometry is up to an order of magnitude. %U https://www.sv-jme.eu/article/lockin-interferometry-principle-and-applications-in-nde/ %0 Journal Article %R 10.5545/sv-jme.2010.169 %& 183 %P 9 %J Strojniški vestnik - Journal of Mechanical Engineering %V 57 %N 3 %@ 0039-2480 %8 2018-06-28 %7 2018-06-28
Menner, Philipp, Henry Gerhard, & Gerd Busse. "Lockin-Interferometry: Principle and Applications in NDE." Strojniški vestnik - Journal of Mechanical Engineering [Online], 57.3 (2011): 183-191. Web. 20 Dec. 2024
TY - JOUR AU - Menner, Philipp AU - Gerhard, Henry AU - Busse, Gerd PY - 2011 TI - Lockin-Interferometry: Principle and Applications in NDE JF - Strojniški vestnik - Journal of Mechanical Engineering DO - 10.5545/sv-jme.2010.169 KW - Lockin-ESPI; Lockin-Shearography; defect-selective imaging; interferometric depth profiling N2 - Interferometry is relevant for non-destructive evaluation (NDE) since dimensional changes much smaller than an optical wavelength result in detectable signals. Fringe images obtained with Electronic-Speckle-Pattern-Interferometry (ESPI) or shearography display changes of surface topography between two states of an object, usually using a static load. Usually, hidden defects are found by comparing the observed fringe pattern to the one obtained on an intact reference component and to attribute observed differences to a defect. Our approach is a periodical object illumination with light that is absorbed in the surface to generate heat and a corresponding modulation of thermal expansion. At the same time fringe images are recorded (either with ESPI or shearography) to give a stack. Subsequently, each image is unwrapped and thereafter the time-dependent content of each pixel is Fourier transformed at the excitation frequency, so the result is local amplitude and phase of the modulated response at this frequency. The phase image displays local delay between excitation and response. This phase change depends on the depth where the defect is located since thermal waves are involved. In this paper, NDE-examples obtained using this new technique are presented. It is also shown how the achieved improvement as compared to conventional interferometry is up to an order of magnitude. UR - https://www.sv-jme.eu/article/lockin-interferometry-principle-and-applications-in-nde/
@article{{sv-jme}{sv-jme.2010.169},
author = {Menner, P., Gerhard, H., Busse, G.},
title = {Lockin-Interferometry: Principle and Applications in NDE},
journal = {Strojniški vestnik - Journal of Mechanical Engineering},
volume = {57},
number = {3},
year = {2011},
doi = {10.5545/sv-jme.2010.169},
url = {https://www.sv-jme.eu/article/lockin-interferometry-principle-and-applications-in-nde/}
}
TY - JOUR AU - Menner, Philipp AU - Gerhard, Henry AU - Busse, Gerd PY - 2018/06/28 TI - Lockin-Interferometry: Principle and Applications in NDE JF - Strojniški vestnik - Journal of Mechanical Engineering; Vol 57, No 3 (2011): Strojniški vestnik - Journal of Mechanical Engineering DO - 10.5545/sv-jme.2010.169 KW - Lockin-ESPI, Lockin-Shearography, defect-selective imaging, interferometric depth profiling N2 - Interferometry is relevant for non-destructive evaluation (NDE) since dimensional changes much smaller than an optical wavelength result in detectable signals. Fringe images obtained with Electronic-Speckle-Pattern-Interferometry (ESPI) or shearography display changes of surface topography between two states of an object, usually using a static load. Usually, hidden defects are found by comparing the observed fringe pattern to the one obtained on an intact reference component and to attribute observed differences to a defect. Our approach is a periodical object illumination with light that is absorbed in the surface to generate heat and a corresponding modulation of thermal expansion. At the same time fringe images are recorded (either with ESPI or shearography) to give a stack. Subsequently, each image is unwrapped and thereafter the time-dependent content of each pixel is Fourier transformed at the excitation frequency, so the result is local amplitude and phase of the modulated response at this frequency. The phase image displays local delay between excitation and response. This phase change depends on the depth where the defect is located since thermal waves are involved. In this paper, NDE-examples obtained using this new technique are presented. It is also shown how the achieved improvement as compared to conventional interferometry is up to an order of magnitude. UR - https://www.sv-jme.eu/article/lockin-interferometry-principle-and-applications-in-nde/
Menner, Philipp, Gerhard, Henry, AND Busse, Gerd. "Lockin-Interferometry: Principle and Applications in NDE" Strojniški vestnik - Journal of Mechanical Engineering [Online], Volume 57 Number 3 (28 June 2018)
Strojniški vestnik - Journal of Mechanical Engineering 57(2011)3, 183-191
© The Authors, CC-BY 4.0 Int. Change in copyright policy from 2022, Jan 1st.
Interferometry is relevant for non-destructive evaluation (NDE) since dimensional changes much smaller than an optical wavelength result in detectable signals. Fringe images obtained with Electronic-Speckle-Pattern-Interferometry (ESPI) or shearography display changes of surface topography between two states of an object, usually using a static load. Usually, hidden defects are found by comparing the observed fringe pattern to the one obtained on an intact reference component and to attribute observed differences to a defect. Our approach is a periodical object illumination with light that is absorbed in the surface to generate heat and a corresponding modulation of thermal expansion. At the same time fringe images are recorded (either with ESPI or shearography) to give a stack. Subsequently, each image is unwrapped and thereafter the time-dependent content of each pixel is Fourier transformed at the excitation frequency, so the result is local amplitude and phase of the modulated response at this frequency. The phase image displays local delay between excitation and response. This phase change depends on the depth where the defect is located since thermal waves are involved. In this paper, NDE-examples obtained using this new technique are presented. It is also shown how the achieved improvement as compared to conventional interferometry is up to an order of magnitude.