Pixelated Carrier Phase-Shifting Shearography Using Spatiotemporal Low-Pass Filtering Algorithm

Yan, Ping; Liu, Xiangwei; Wu, Shuangle; Sun, Fangyuan; Zhao, Qihan; Wang, Yonghong

doi:10.3390/s19235185

Cited by 8 publications

(3 citation statements)

References 32 publications

(35 reference statements)

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“…Therefore, the practical application of the system is very limited. Yan et al 18 proposed a pixelated carrier method based on a polarization camera to achieve free adjustment of the shearing amount; however, the polarization camera is expensive and the system is complex.…”

Section: Introductionmentioning

confidence: 99%

A robust phase extraction method for overcoming spectrum overlapping in shearography

Liu¹,

Yan²,

Wang³

2023

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The advantage of spatial phase-shifting shearography is its ability to extract the phase from a single speckle pattern; however, it often faces spectrum overlapping, which seriously affects phase quality. In this paper, we propose a shearography phase-extraction method based on windowed Fourier ridges, which can effectively extract phase information even in the presence of severe spectrum overlapping. A simple and efficient method was applied to determine the parameters of the windowed Fourier ridges, and a linear variation window was used to match the phase-extraction requirements for different frequency coordinates. A numerical simulation was quantitatively conducted to compare the phase-extraction results of the proposed method with those of the conventional method for various cases, and a shearography system was built with two types of objects to demonstrate the feasibility of the proposed method.

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Section: Introductionmentioning

confidence: 99%

A robust phase extraction method for overcoming spectrum overlapping in shearography

Liu¹,

Yan²,

Wang³

2023

gxjzz

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“…Some commonly used optical measurement technologies are holographic interferometry 11 and digital speckle pattern interferometry 12 . Digital speckle pattern interferometry is often applied for displacement measurement, strain analysis, dynamic testing, and nondestructive flaw detection of materials and structures in aerospace, automobile, ship manufacturing, and relevant other fields because it can cover a full-field, involves real-time measurement, capable of online detection, and has high sensitivity and high precision 13 . In recent years, with the development and improvement of this technology, the combination of speckle pattern interference system and microscopic imaging system has attracted attention for measurement of microstructure.…”

Section: Introductionmentioning

confidence: 99%

Synchronous measurement of surface deformation and gradient distribution in microstructures

Wang

Yin

et al. 2022

Opt. Eng.

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In the traditional microfield speckle pattern interference measurement system, due to the use of high-magnification objective lens, the working distance is small and the shearing device cannot be introduced to implement shearography measurement. Thus the distribution of the deformation gradient on a microstructure surface cannot be measured. A system for the synchronous measurement of the surface deformation and gradient distribution of a microstructure was designed. Through the combination of focusing lens, convex lens, and low-magnification objective lens, the microstructure surface was clearly magnified and the internal distance of the system was enlarged. Thus the shearing device can be introduced to realize the shearography measurement under the microfield view. The synchronous full-field measurement of the structural surface deformation and its gradient distribution was further realized by the introduction of a reference light and designing of an optical path switch. In addition, the designed system had a zoom feature, which can facilitate the measurement in variable field of view in a certain range. The feasibility of the system was verified by theoretical analysis and experiment, and the practicability was validated by testing the chip and circuit board.

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“…The interferometric technique has been applied on shearography in [17] with relatively low signal-to-noise ratio using a Mach-Zehnder interferometer configuration. A more promising set-up of the SPS-DS has been developed by the combination of spatiotemporal phase-shifting technique and 3D Fourier transform [18,19] with pixelated SPS-DS by fully using simple configuration of the Michelson interferometry-based setup on shearography [20]. The approach achieved a relatively ideal phase map of a hollow artificial cylinder with uniformly exerted air pressure as the loading method.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Wind Turbine Blade Inspection Using Micro-Polarisation Spatial Phase Shift Digital Shearography

Tokhi

Marks

et al. 2021

Applied Sciences

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Shearography, as a novel non-destructive evaluation technique, has shown notable ability in the detection of composite materials. However, in current shearography practices, the phase shifting and loading methods applied are mainly static. For instance, vacuum hood or force loading facilities are often used in phase-shifting shearography, and these are hard to realise with robotic control, especially for on-board inspection. In this study, a dynamic process for detecting defects in the subsurface of a wind turbine blade (WTB) using spatial phase shift with dynamic thermal loading was proposed. The WTB sample underwent a dynamic thermal loading operation, and its status is captured by a Michelson interferometric-based spatial phase shift digital shearography system using a pixelated micro-polarisation array sensor. The captured images were analysed in a 2D frequency domain and low-pass filtered for phase map acquisition. The initial phase maps underwent a window Fourier filtering process and were integrated to produce a video sequence for realisation of visualising the first derivative of the displacement in the process of thermal loading. The approach was tested in experimental settings and the results obtained were presented and discussed. A comparative assessment of the approach with shearography fringe pattern analysis and temporal phase shift technique is also presented and discussed.

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Pixelated Carrier Phase-Shifting Shearography Using Spatiotemporal Low-Pass Filtering Algorithm

Cited by 8 publications

References 32 publications

A robust phase extraction method for overcoming spectrum overlapping in shearography

A robust phase extraction method for overcoming spectrum overlapping in shearography

Synchronous measurement of surface deformation and gradient distribution in microstructures

Dynamic Wind Turbine Blade Inspection Using Micro-Polarisation Spatial Phase Shift Digital Shearography

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