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.
journal_name
Ultrasonicsjournal_title
Ultrasonicsauthors
Benammar A,Drai R,Guessoum Adoi
10.1016/j.ultras.2013.09.004subject
Has Abstractpub_date
2014-02-01 00:00:00pages
676-83issue
2eissn
0041-624Xissn
1874-9968pii
S0041-624X(13)00264-3journal_volume
54pub_type
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