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Influence of thresholding procedures in ultrasonic grain noise reduction using wavelets

✍ Scribed by J.C. Lázaro; J.L. San Emeterio; A. Ramos; J.L. Fernández-Marrón

Book ID
104263513
Publisher
Elsevier Science
Year
2002
Tongue
English
Weight
156 KB
Volume
40
Category
Article
ISSN
0041-624X

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✦ Synopsis

Wavelet transform based techniques are used for signal-to-noise ratio (SNR) enhancement in ultrasonic non-destructive testing and evaluation of strong sound scattering materials. The overall denoising performance of a wavelet signal processor is conditioned by several processing parameters, including the type of wavelet, thresholding method, and threshold selection rules. Different thresholding procedures and threshold selection rules are analysed in this paper using the discrete wavelet transform and decomposition level dependent thresholds. Global performance is evaluated by means of the SNR enhancement using synthetic grain noise registers with an incrusted flaw signal, with different values of the input SNR, and experimental ultrasonic traces acquired from a carbon fibre reinforced plastic composite block.

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