Shearography and its applications – a chronological review

Sirohi, R. S.

doi:10.37188/lam.2022.001

Cited by 15 publications

(6 citation statements)

References 361 publications

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“…DSSPI, also known as shearography, is used for high-precision, nondestructive measurement of surface deformation. It has gained widespread industrial acceptance for nondestructive testing [26,27]. Figure 1 illustrates the schematic diagram of the DSSPI system, which captures speckle fringe patterns.…”

Section: Dsspimentioning

confidence: 99%

A Vision-Based Bolt Looseness Detection Method for a Multi-Bolt Connection

Deng,

Sa,

et al. 2024

Applied Sciences

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Many vision-based bolt looseness detection methods that directly observe the bolts have been developed. However, these methods have many limitations in terms of the conditions and processes of their implementation. To address these problems, this paper proposed a fully automated vision-based bolt looseness detection method for a rigid multi-bolt connection. The proposed method combines digital shearing speckle pattern interferometry (DSSPI) and recurrent neural network (RNN) and involves capturing speckle fringe patterns under various looseness cases using the DSSPI system and classifying these patterns with an RNN model to detect the loose bolts. The proposed method can detect all the bolts within the measured surface at one time, which is efficient. On the other hand, it eliminates the need for prior information such as the initial angle and position of each bolt. It can even detect unseen bolts in multi-bolt connections, making it applicable for connections in complex structures in which occlusion often occurs. Additionally, the method eliminates the complex process of distortion rectification. These features make the method achieve a single-judgment time (four bolts at one detection) of only 4.70 millisecond with a detection accuracy over 99%, which has potential for the real-time detection of loose bolts in multi-bolt connections.

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Section: Dsspimentioning

confidence: 99%

A Vision-Based Bolt Looseness Detection Method for a Multi-Bolt Connection

Deng,

Sa,

et al. 2024

Applied Sciences

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“…Holographic technology has the capability to reproduce the seven-dimensional light field function completely, which is regarded as the most perfect display technology. [1] It has diverse applications in measurement, [2][3][4][5][6][7] display, [8][9][10][11][12] storage, [13][14][15] etc. Computer-generated hologram (CGH) offers lower noise and is unaffected to optical path.…”

Section: Introductionmentioning

confidence: 99%

Accelerated generation of holograms with ultra-low memory symmetrically high-compressed look-up table

Yang 杨,

Zhu 朱,

Sun 孙

et al. 2024

Chinese Phys. B

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Computer-generated holography technology has been widely applied, and as research in this field deepens, the demand for memory and computational power in small AR and VR devices continues to increase. This paper introduces a hologram generation method, symmetrically high-compressed look-up table method, which can reduce memory usage by 50%. In offline computing, the half of basic horizontal and vertical modulation factors are stored, halving the memory requirements without affecting inline speed. Currently, its potential extends to various holographic applications, including the production of optical diffraction elements.

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“…Shearography is a highly sensitive optical interferometry method 1 . Because of its large measurement field of view and strong vibration-resistant capability, which most optical interference techniques do not feature, shearography has been increasingly studied and applied in the fields of three-dimensional non-destructive testing, material property analysis, and object vibration pattern recognition [2][3][4] .…”

Section: Introductionmentioning

confidence: 99%

A robust phase extraction method for overcoming spectrum overlapping in shearography

Liu¹,

Yan²,

Wang³

2023

gxjzz

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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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Shearography and its applications – a chronological review

Cited by 15 publications

References 361 publications

A Vision-Based Bolt Looseness Detection Method for a Multi-Bolt Connection

A Vision-Based Bolt Looseness Detection Method for a Multi-Bolt Connection

Accelerated generation of holograms with ultra-low memory symmetrically high-compressed look-up table

A robust phase extraction method for overcoming spectrum overlapping in shearography

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