Russian Journal of Nondestructive Testing

, Volume 48, Issue 11, pp 649–661 | Cite as

Instantaneous frequency estimation used for the classification of echo signals from different reflectors

Acoustic Methods


A comparative analysis of the frequency parameters of echo signals from artificial reflectors of different shapes and from a natural spill-type flaw has been performed. The use of the instantaneous frequencies of ultrasonic signals that correspond to certain instants inside a pulse was suggested as an informative parameter for determining the flaw type. Instantaneous frequency is estimated based on the algorithm of the continuous wavelet transform, which increases the noise immunity of the method. It is shown that for the algorithm to be practically implemented it is appropriate to present the results in the form of dimensionless parameters, namely, normalized frequency deviations determined between the pulse center, edge, and tail. Their joint application makes it possible, in particular, to reliably distinguish echo signals that are reflected at junction flaws that rise to the surface of a test object (notches, dihedral angles, and spills of the weld joints), flat specimen surfaces, and local flaws, such as cylindrical side through holes and flat bottom drills.


instantaneous frequency normalized frequency deviation reflectors signals flaw shape 


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  1. 1.
    Shcherbinskii, V.G. and Belyi, V.E., A New Informative Parameter of the Flaw Nature upon Ultrasonic Testing, Defektoskopiya, 1975, no. 3, pp. 27–36.Google Scholar
  2. 2.
    Whittaker, I.S. and Iessop, T.J., Ultrasonic Detection and Measurements of Defects in Stainless Steel, Br. J. Non-Destr. Test., 1981, vol. 23, no. 6, pp. 293–303.Google Scholar
  3. 3.
    Gurvich, A.K. and Kuz’mina, L.I., Scattering Indicatrices as a Source of Additional Data on Detected Flaws, Defektoskopiya, 1970, no. 6, pp. 47–56.Google Scholar
  4. 4.
    Vopilkin, A.Kh., Difraktsionnye metody v ul’trazvukovom nerazrushayushchem kontrole (Diffraction Methods in Ultrasonic Nondestructive Testing), Moscow: Izd. NTO “Priborprom”, 1989.Google Scholar
  5. 5.
    Perevalov, S.P., The Study of Geometrical and Acoustic Characteristics of Erosion Reflectors, Defektoskopiya, 1994, no. 9, pp. 15–31.Google Scholar
  6. 6.
    Barkhatov, V.A., Application of Window Functions in Problems of Pattern Recognition of Ultrasonic Signals, Russ. J. Nondestr. Test., 2010, vol. 46, no. 10, pp. 711–717.CrossRefGoogle Scholar
  7. 7.
    Bazulin, E.G., Reconstruction of Flaw Images by the C-SAFT Method from Echo Signals Measured by an Antenna Array in the Triple-Scanning Mode, Russ. J. Nondestr. Test., 2012, vol. 48, no. 1, pp. 1–14.CrossRefGoogle Scholar
  8. 8.
    Perov, D.V., Rinkevich, A.B., and Nemytova, O.V., Interaction of Pulse Ultrasonic Signals with Reflectors of Different Types, Russ. J. Nondestr. Test., 2007, vol. 43, no. 6, pp. 369–377.CrossRefGoogle Scholar
  9. 9.
    Vainshtein, L.A. and Vakman, D.E., Razdelenie chastot v teorii kolebanii i voln (Separation of Frequencies in the Theory of Oscillations and Waves), Moscow: Nauka, 1983.Google Scholar
  10. 10.
    Rinkevich, A.B., Nemytova, O.V., and Perov, D.V., Comparison of Frequency Features of Pulse Echoes from Different Reflectors, ISRN Mech. Eng., 2011, p. 371514.Google Scholar
  11. 11.
    Perov, D.V., Rinkevich, A.B., and Kusonskii, O.A., Veivletnyi analiz sverkhdlinnoperiodnykh seismicheskikh ostsillyatsii. Sbornik trudov XVI Sessii Rossiiskogo akusticheskogo obshchestva (The Wavelet Analysis of Super-Long-Period Seismic Vibrations), Moscow: GEOS, 2005, vol. 1, pp. 279–282.Google Scholar
  12. 12.
    Perov, D.V. and Rinkevich, A.B., Using Wavelets for Analyzing Ultrasonic Fields Detected by a Laser Interferometer. Basic Concepts of the Wavelet Analysis, Russ. J. Nondestr. Test., 2001, vol. 37, no. 12, pp. 879–888.CrossRefGoogle Scholar
  13. 13.
    Perov, D.V. and Rinkevich, A.B., Using the Different Types of Wavelet Transform for Analyzing Acoustic Fields and Signals in Elastic Media. New Research on Acoustics, Weiss, B.N., Ed., New York: Nova Science Publishers, 2008, pp. 65–109.Google Scholar
  14. 14.
    Dobeshi, I., Desyat’ lektsii po veivletam (Ten Lectures on Wavelets), Izhevsk: NITs “Regulyarnaya i Khaoticheskaya Dinamika”, 2001.Google Scholar
  15. 15.
    Danilov, V.N., Estimating the Parameters of Signals Observed during Ultrasonic Testing of a Cylindrical Article with a Normal Probe on the End Surface, Russ. J. Nondestr. Test., 2005, vol. 41, no. 2, pp. 102–114.CrossRefGoogle Scholar
  16. 16.
    Perov, D.V. and Rinkevich, A.B., Acoustic Pulse Signal Diffraction from Different Reflectors in an Elastic Medium, Insight, 2008, vol. 50, no. 4, pp. 216–217.CrossRefGoogle Scholar
  17. 17.
    GOST (State Standard) 14782-86: Nondestructive Testing. Weld Joints. Ultrasonic Methods.Google Scholar

Copyright information

© Pleiades Publishing, Ltd. 2012

Authors and Affiliations

  • O. V. Nemytova
    • 1
  • A. B. Rinkevich
    • 1
  • D. V. Perov
    • 1
  1. 1.Institute of Metal Physics, Ural DivisionRussian Academy of SciencesYekaterinburgRussia

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