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International Journal of Corrosion
Volume 2017, Article ID 7925404, 7 pages
https://doi.org/10.1155/2017/7925404
Research Article

The Discrete Wavelet Transform and Its Application for Noise Removal in Localized Corrosion Measurements

1Engineering Institute, Autonomous University of Baja California, Boulevard Benito Juarez, Insurgentes Este, 21280 Mexicali, BC, Mexico
2National Center of Metallurgical Research (CENIM) Madrid, The Spanish State Council for Scientific Research (CSIC), Madrid, Spain

Correspondence should be addressed to Rogelio Ramos; xm.ude.cbau@isomarr

Received 30 January 2017; Accepted 24 April 2017; Published 4 June 2017

Academic Editor: Flavio Deflorian

Copyright © 2017 Rogelio Ramos et al. 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

The present work discusses the problem of induced external electrical noise as well as its removal from the electrical potential obtained from Scanning Vibrating Electrode Technique (SVET) in the pitting corrosion process of aluminum alloy A96061 in 3.5% NaCl. An accessible and efficient solution of this problem is presented with the use of virtual instrumentation (VI), embedded systems, and the discrete wavelet transform (DWT). The DWT is a computational algorithm for digital processing that allows obtaining electrical noise with Signal to Noise Ratio (SNR) superior to those obtained with Lock-In Amplifier equipment. The results show that DWT and the threshold method are efficient and powerful alternatives to carry out electrical measurements of potential signals from localized corrosion processes measured by SVET.