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Shock and Vibration
Volume 6 (1999), Issue 5-6, Pages 267-272
http://dx.doi.org/10.1155/1999/175750

The De-Noising of Sonic Echo Test Data through Wavelet Transform Reconstruction

J.N. Watson,1 P.S. Addison,1 and A. Sibbald2

1School of the Built Environment, Napier University, Merchiston Campus, 10 Colinton Road, Edinburgh, EH10 5DT, Scotland, UK
2Faculty of Engineering, Napier University, Merchiston Campus, 10 Colinton Road, Edinburgh, EH10 5DT, Scotland, UK

Received 1 June 1999; Revised 27 September 1999

Copyright © 1999 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper presents the results of feasibility study into the application of the wavelet transform signal processing method to sonic based non-destructive testing techniques. Finite element generated data from cast in situ foundation piles were collated and processed using both continuous and discrete wavelet transform techniques. Results were compared with conventional Fourier based methods. The discrete Daubechies wavelets and the continuous Mexican hat wavelet were used and their relative merits investigated. It was found that both the continuous Mexican hat and discrete Daubechies D8 wavelets were significantly better at locating the pile toe compared than the Fourier filtered case. The wavelet transform method was then applied to field test data and found to be successful in facilitating the detection of the pile toe.