Denoising time-domain induced polarisation data using wavelet techniques
Ravin N. Deo 1 3 James P. Cull 21 School of Engineering and Physics, Faculty of Science Technology and Environment, University of the South Pacific, Suva, Fiji.
2 School of Earth, Atmosphere and Environment, Monash University, Clayton, Vic. 3800, Australia.
3 Corresponding author. Email: ravin.deo@gmail.com
Exploration Geophysics 47(2) 108-114 https://doi.org/10.1071/EG13077
Submitted: 16 September 2013 Accepted: 19 April 2015 Published: 8 May 2015
Abstract
Time-domain induced polarisation (TDIP) methods are routinely used for near-surface evaluations in quasi-urban environments harbouring networks of buried civil infrastructure. A conventional technique for improving signal to noise ratio in such environments is by using analogue or digital low-pass filtering followed by stacking and rectification. However, this induces large distortions in the processed data. In this study, we have conducted the first application of wavelet based denoising techniques for processing raw TDIP data. Our investigation included laboratory and field measurements to better understand the advantages and limitations of this technique. It was found that distortions arising from conventional filtering can be significantly avoided with the use of wavelet based denoising techniques. With recent advances in full-waveform acquisition and analysis, incorporation of wavelet denoising techniques can further enhance surveying capabilities. In this work, we present the rationale for utilising wavelet denoising methods and discuss some important implications, which can positively influence TDIP methods.
Key words: electrical geophysics, induced polarisation, processing, wavelet.
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