Application of Gabor transform on cylindrical guided waves to detect defects in underground pipes

Rais Ahmad, Tribikram Kundu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Defects in underground pipes are detected by applying Gabor transforms on experimental guided wave signals and comparing the experimental group velocity plots with the theoretical group velocity dispersion curves. Gabor transform, which is a powerful signal processing tool, maps a signal into a two-dimensional space of time and frequency. Thus it provides information about both when and at what frequency a signal arrives. Focus of this paper is to study the applicability of cylindrical guided waves to detect defects in underground pipes using Gabor transform. Cylindrical guided waves are generated by piezo-electric transducers. Guided waves are propagated through pipes that are buried in the soil by placing transmitters on one end of the pipes and the receivers on the other end. The recorded signals are then processed using 2-D Gabor Transform or Short Time Fourier Transform (STFT). Gabor transform converts the timeamplitude signal into a time frequency signal which reveals the group velocities hidden in the signal. These experimentally obtained group velocities are then compared with the theoretical velocities for cylindrical pipes embedded in the soil. From the comparison of the theoretical and experimental group velocities, an effort has been made to identify which modes are propagating through the embedded defective pipes and which modes are having difficulty to propagate through the defective pipe wall. From this knowledge pipe wall defects can be detected.

Original languageEnglish (US)
Title of host publicationHealth Monitoring of Structural and Biological Systems 2007
DOIs
StatePublished - Nov 5 2007
EventHealth Monitoring of Structural and Biological Systems 2007 - San Diego, CA, United States
Duration: Mar 19 2007Mar 22 2007

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume6532
ISSN (Print)0277-786X

Other

OtherHealth Monitoring of Structural and Biological Systems 2007
CountryUnited States
CitySan Diego, CA
Period3/19/073/22/07

Keywords

  • Cylindrical guided wave
  • Defect detection
  • Gabor transform
  • Pipe inspection
  • Short time fourier transform
  • Wavelet analysis

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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  • Cite this

    Ahmad, R., & Kundu, T. (2007). Application of Gabor transform on cylindrical guided waves to detect defects in underground pipes. In Health Monitoring of Structural and Biological Systems 2007 [65320P] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 6532). https://doi.org/10.1117/12.715673