• Aucun résultat trouvé

Ultrasonic flaw detection using thresholdmodified S-transform

N/A
N/A
Info
Télécharger
Protected

Academic year: 2021

Partager "Ultrasonic flaw detection using thresholdmodified S-transform"

Copied!
1
0
0

Chargement.... (Voir le texte intégral maintenant)

Texte intégral

(1)

Ultrasonics

Volume 54, Issue 2, 2014, Pages 676-683

Ultrasonic flaw detection using threshold modified S-transform

Abdessalem BENAMMAR, Redouane DRAI, Abderrezak GUESSOUM

Abstract: Interference noising originating from the ultrasonic testing defect signal seriously influences the accuracy of the signal extraction and defect location. Time–frequency analysis methods are mainly used to improve the defects detection resolution. In fact, the S-transform, a hybrid of the Short time Fourier transform (STFT) and wavelet transform (WT), has a time frequency resolution which is far from ideal. In this paper, a new modified S-transform based on thresholding technique, which offers a better time frequency resolution compared to the original S-transform is proposed. The improvement is achieved by the introduction of a new scaling rule for the Gaussian window used in S-transform. Simulation results are presented and show correct time frequency information of multiple Gaussian echoes under low signal-to-noise ratio (SNR) environment. In addition, experimental results demonstrate better and reliable detection of close echoes drowned in the noise.

Keywords : Flaw detection, Ultrasonic signal, Time–frequency signal analysis, Modified S-transform

Centre de Recherche en Technologies Industrielles - CRTI - www.crti.dz

Powered by TCPDF (www.tcpdf.org)

Références

Télécharger maintenant ( PDF - 1 Page - 7.69 KB )

Documents relatifs

HIGH RESOLUTION FOURIER TRANSFORM SPECTROSCOPY

The instrument is currently being used to measure at high resolution the vibrational spectrum of gaseous hydrogen induced by a strong electric field.. To attack such problems

Speed Transform, a New Time-Varying Frequency Analysis Technique

Whereas valuable so- lutions exist, for instance based on angular resampling, this paper proposed a new speed transform which inherits all the properties of the Fourier transform –

Radon Transform on the Torus

The simple example of lines in Euclidean space has suggested naming X-ray transform the corresponding integral operator, associating to a function f its integrals Rf() along

Time Frequency and Wavelet Transform Appliedto Ultrasonics NDE

Abstract : In this paper, we contribute by the development of some signal processing techniques based on time frequency and wavelet transform in order to enhance the sensibility

Transform´ ee de Laplace et transform´ ee en Z

Transform´ee de Laplace et transform´ee en Z 1/2..

Time-Space Transform Model for Timing The

If we place the bistable units of each layer relatively to the number of connections they receive from the oscillations generator, then we can see time as it passes (fig.. In

The Fourier-based Synchrosqueezing Transform

The short-time Fourier transform (STFT) and continuous wavelet transform (CWT) are intensively used to analyze and process multicomponent signals, ie superpositions of mod-

Reassigned Time-Frequency Representations of Discrete Time Signals and Application to the Constant Q Transform

Similarly to what has been done for the time coordinate, the expression of the time-frequency representation at point pt, ν q as the sum of a mass function Φ t,ν , proved in