Wavelet Transform Signal Processing Applied to Ultrasonics

Abbate, A.; Frankel, J.; Das, P.

doi:10.1007/978-1-4613-0383-1_97

Cited by 13 publications

(6 citation statements)

References 11 publications

(10 reference statements)

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“…where ψ* is the complex conjugation of the mother wavelet (a continuous function in both the time domain and the frequency domain). A scale factor a either stretches (a is large), or compresses (a is small) the signal, where a = ωo / ω, ω is the angular frequency and ω o is the angular frequency shift, while b is the signal's time shift [14][15][16]. The main purpose of the mother wavelet is to provide a source function to generate the daughter wavelets which are simply the translated and scaled versions of the mother wavelet.…”

Section: Theoretical Considerations 21 Wavelet Transformmentioning

confidence: 99%

Wavelet Transform Applied to Internal Defect Detection by Means of Laser Ultrasound

Selim¹,

Moctezuma²,

Delgado-Prieto³

et al. 2019

Wavelet Transform and Complexity

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Laser-generated ultrasound represents an interesting nondestructive testing technique that is being investigated in the last years as performative alternative to classical ultrasonic-based approaches. The greatest difficulty in analyzing the acoustic emission response is that an in-depth knowledge of how acoustic waves propagate through the tested composite is required. In this regard, different signal processing approaches are being applied in order to assess the significance of features extracted from the resulting analysis. In this study, the detection capabilities of internal defects in a metallic sample are proposed to be studied by means of the time-frequency analysis of the ultrasonic waves resulting from laser-induced thermal mechanism. In the proposed study, the use of the wavelet transform considering different wavelet variants is considered due to its multi-resolution time-frequency characteristics. Also, a significant time-frequency technique widely applied in other fields of research is applied, the synchrosqueezed transform.

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Section: Theoretical Considerations 21 Wavelet Transformmentioning

confidence: 99%

Wavelet Transform Applied to Internal Defect Detection by Means of Laser Ultrasound

Selim¹,

Moctezuma²,

Delgado-Prieto³

et al. 2019

Wavelet Transform and Complexity

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show abstract

“…[29]. Due to its multi-resolution characteristics for signal decomposition, it has attracted significant attention from many researchers in the area of ultrasonic NDT [30][31][32][33][34][35][36].…”

Section: Introductionmentioning

confidence: 99%

Improving Depth Resolution of Ultrasonic Phased Array Imaging to Inspect Aerospace Composite Structures

Mohammadkhani

Fragonara

et al. 2020

Sensors

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In this paper, we present challenges and achievements in development and use of a compact ultrasonic Phased Array (PA) module with signal processing and imaging technology for autonomous non-destructive evaluation of composite aerospace structures. We analyse two different sets of ultrasonic scan data, acquired from 5 MHz and 10 MHz PA transducers. Although higher frequency transducers promise higher axial (depth) resolution in PA imaging, we face several signal processing challenges to detect defects in composite specimens at 10 MHz. One of the challenges is the presence of multiple echoes at the boundary of the composite layers called structural noise. Here, we propose a wavelet transform-based algorithm that is able to detect and characterize defects (depth, size, and shape in 3D plots). This algorithm uses a smart thresholding technique based on the extracted statistical mean and standard deviation of the structural noise. Finally, we use the proposed algorithm to detect and characterize defects in a standard calibration specimen and validate the results by comparing to the designed depth information.

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“…In this paper we present a flaw signature estimation approach which utilizes the Wiener filter [1][2][3][4][5] along with a wavelet based procedure [6][7][8][9][10][11][12][13][14][15] to achieve both deconvolution and reduction of acoustic noise. In related ealier work by Patterson et al [6], the wavelet transform was applied to certain components of the Wiener filter, and coefficient chopping was used to reduce acoustic noise.…”

Section: Introductionmentioning

confidence: 99%

An Application of Wavelet Signal Processing to Ultrasonic Nondestructive Evaluation

Nevel

DeFacio

Neal

1996

Review of Progress in Quantitative Nondestructive Evaluation

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Wavelet Transform Signal Processing Applied to Ultrasonics

Cited by 13 publications

References 11 publications

Wavelet Transform Applied to Internal Defect Detection by Means of Laser Ultrasound

Wavelet Transform Applied to Internal Defect Detection by Means of Laser Ultrasound

Improving Depth Resolution of Ultrasonic Phased Array Imaging to Inspect Aerospace Composite Structures

An Application of Wavelet Signal Processing to Ultrasonic Nondestructive Evaluation

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