Spatial phase-shift digital shearography for simultaneous measurements in three shearing directions based on adjustable aperture multiplexing

Yan, Ping; Sun, Fangyuan; Dan, Xizuo; Zhao, Qihan; Wang, Yonghong; Lu, Yu

doi:10.1117/1.oe.58.5.054105

Cited by 18 publications

(6 citation statements)

References 27 publications

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“…where D is the distance from the image plane to exit pupil plane [32]. 2πi λD ξx and 2πi λD ηy are the spatial carrier frequencies introduced by aperture misalignment.…”

Section: Methodsmentioning

confidence: 99%

“…where D is the distance from the image plane to exit pupil plane [32]. The interferogram on the imaging plane can be expressed as follows: As shown in Figure 3,         ,0 , ,0 , 0, , 0,      are the center coordinates of the four apertures of imaging beams x1, x2, y1, and y2, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…where D is the distance from the image plane to exit pupil plane [32]. The interferogram on the imaging plane can be expressed as follows: The interferogram on the imaging plane can be expressed as follows:…”

Section: Methodsmentioning

confidence: 99%

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Measurement of In-Plane Displacement in Two Orthogonal Directions by Digital Speckle Pattern Interferometry

et al. 2019

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The measurement of in-plane displacement in two orthogonal directions is of considerable significance for modern industries. This paper reports on a spatial carrier phase-shift digital speckle pattern interferometry (DSPI) for the simultaneous measurement of in-plane displacement in two orthogonal directions. The object is illuminated from a single direction and observed from four symmetrical directions simultaneously. One pair of the four observation directions is sensitive to in-plane displacement in one direction, and the other pair is sensitive to in-plane displacement in the perpendicular direction, resulting in the displacement in two directions being measured independently. The polarization property of light is used to avoid cross-interference between the two pairs of beams. Spatial carrier frequencies are generated by aperture misalignment, and the displacement in two directions is modulated onto the same interferogram. With a spatial carrier phase-shift technique, the displacement can be separated in the frequency domain and the phase can be evaluated from a single interferogram in real time. The capability of DSPI is described by theoretical discussions and experiments. Appl. Sci. 2019, 9, 3882 2 of 10 (DSPI) [3,12]. The sensitivity of Moiré interferometry and DSPI is higher than that of DIC, and the set-up of DSPI is simpler than that of Moiré interferometry. Because of the high sensitivity and flexibility of DSPI, it has been well-accepted in experimental mechanics, displacement and displacement measurements, and strain measurements.In DSPI, in-plane displacement is measured by evaluating the phase difference of two recorded speckle interferograms under load. The surface under the test is illuminated from two symmetrical directions with a single direction of observation [13], or is observed from two symmetrical directions with a single direction of illumination [14]. The measurement of a surface displacement in two orthogonal directions is often required for the complete characterization of displacement. In traditional DSPI, in-plane displacement is measured in the single direction, depending on the illumination or observation direction. For example, if the surface is illuminated from two symmetrical directions, the measured displacement is in the vector direction, which is the subtraction of the vector directions of the two illumination beams. To measure the displacement in the perpendicular direction, the illumination beams must be rotated 90 degrees around the viewing axis. To make a system sensitive to displacement in two orthogonal directions, two pairs of beams, with different directions, should sequentially illuminate the surface. Thus, two separate interferograms can be recorded and combined vectorially [1,3,8,15]. To avoid cross-interference between the two pairs of beams, they should not illuminate the surface at the same time. Sequential measurement takes more time than usual, making the simultaneous measurement of transient or non-repeatable events, that require displacement in two orth...

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“…where D is the distance from the image plane to exit pupil plane [32]. 2πi λD ξx and 2πi λD ηy are the spatial carrier frequencies introduced by aperture misalignment.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Measurement of In-Plane Displacement in Two Orthogonal Directions by Digital Speckle Pattern Interferometry

et al. 2019

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“…Similarly, Yan et al 10 proposed a shearography scheme based on the multiaperture, singleimage configuration. The optical configuration is adjusted to obtain spatial phase shift with sensitivity in three directions in the plane.…”

Section: Introductionmentioning

confidence: 99%

“…Similarly, Yan et al 10 . proposed a shearography scheme based on the multiaperture, single-image configuration.…”

Section: Introductionmentioning

confidence: 99%

Measuring material thickness changes through tri-aperture digital speckle pattern interferometry

Barrera

Ealo

2023

Opt. Eng.

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.A configuration for the measurement of thickness changes in materials through one-shot digital speckle pattern interferometry (DSPI) was developed. The phase maps calculation was made by adding carrier fringes by the multiple aperture principle and Fourier Transform Method (FTM). With this setup, interferometry configurations verified that the simultaneous and instantaneous visualization of two opposite faces of a surface is possible. In addition, the combination of the simultaneous results obtained from both sides of the material makes it possible to determine displacements with greater sensitivity or to identify changes in their thickness. The validation and demonstrative tests were carried out with a 1-mm-thick aluminum plate with a 5-mm diameter through hole coated. Thickness changes to 2 μm were measured.

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Measurement of absolute three-dimensional displacement gradients using tri-color quad-beam digital shearography

Li,

Wu,

Tang

et al. 2023

Optoelectron. Lett.

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Spatial phase-shift digital shearography for simultaneous measurements in three shearing directions based on adjustable aperture multiplexing

Cited by 18 publications

References 27 publications

Measurement of In-Plane Displacement in Two Orthogonal Directions by Digital Speckle Pattern Interferometry

Measurement of In-Plane Displacement in Two Orthogonal Directions by Digital Speckle Pattern Interferometry

Measuring material thickness changes through tri-aperture digital speckle pattern interferometry

Measurement of absolute three-dimensional displacement gradients using tri-color quad-beam digital shearography

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