Abstract
A new signal processing technique for separating the reflection of a flaw near a surface from the surface reflection itself is proposed. The method is based on ultrasonic scattering energy function model of flaw close to the material surface. Flaw sensitive component in the model, which corresponding to the low frequency signal, is remained by using a low pass digital filter. In order to make the recognition procedure easier and enhance the recognition effect, a reference signal is introduced to avoid the influence of the surface echo. Thus, the surface flaw is easily and clearly recognized. The good performance of the approach is experimentally verified in laboratory on a steel sample with different man-made surface flaws.
Similar content being viewed by others
References
Ruiz-Reyes, N., Vera-Candeasa, P., Curpian-Alonsoa, J., et al., High-Resolution Pursuit for Detecting Flaw Echoes Close to the Material Surface in Ultrasonic NDT, NDT&E International, 2006, vol. 39, no. 6, pp. 487–492.
Zala, C.A., High-Resolution Inversion of Ultrasonic Traces, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 1992, vol. 39,issue 4, pp. 458–463.
Drai, R., Sellidj, F., Khelil, M., and Benchaala, A., Elaboration of Some Signal Processing Algorithms in Ultrasonic Techniques: Application to Materials NDT, Ultrasonics, 2000, vol. 38,issues 1–8, pp. 503–507.
Lu, X.M., Reid, J.M., Soetanto, K., et al., Cepstrum Technique for Multilayer Structure Characterization, Ultrasonics Symposium, 1990, pp. 1571–1574.
Fritsch, C. and Veca, A., Detecting Small Flaws Near the Interface in Pulse-Echo, Ultrasonics, 2004, vol. 42,issues 1–9, pp. 797–801.
Nobukazu Ido, Hiroaki Hatanaka, et al., Examination of Flaw Detection Near the Surface by the Ultrasonic TOFD Method. Key Engineering Materials, Advances in Nondestructive Evaluation, 2004, vols. 270–273, no. 1, pp. 378–383.
Taszarek, B.J., Method and Apparatus for Ultrasonic Detection of Near-Surface Discontinuities, United States Patent 4380929, http://www.freepatentsonline.com/4380929.html.
Zoran Kuljis and Lareau, J.P., Near Surface Inspection System, United States Patent 4509369, http://www.lree-patentsonline.com/4509369.html.
Author information
Authors and Affiliations
Additional information
Original Russian Text © Song Shoupeng, 2010, published in Defektoskopiya, 2010, Vol. 46, No. 1, pp. 90–96.
The article is published in the original.
Rights and permissions
About this article
Cite this article
Song, S. A new signal processing technique for detecting flaw echoes close to the material surface in ultrasonic NDT. Russ J Nondestruct Test 46, 69–74 (2010). https://doi.org/10.1134/S1061830910010109
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1061830910010109