Quantitative vibration amplitude measurement with time-averaged digital speckle pattern interferometry

Wai On Wong, K. T. Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

15 Citations (Scopus)


A new method of using time-averaged digital speckle pattern interferometry for the quantitative measurement of vibration amplitude was developed. Signal processing techniques especially the Hilbert transformation for quantitative evaluation of the Bessel fringes obtained in time-averaged digital speckle pattern interferometry were explored. The quadrature signal after Hilbert transformation is equivalent to a 90° phase-shifted interferogram for a monotonically increasing or decreasing phase function. An algorithm was developed for Bessel fringe contrast enhancement and phase extraction. The techniques were tested numerically and experimentally. Sub-fringe quantification of the time-averaged vibration fringes is realised with the proposed method. Compared with the commonly used phase shift method which requires a minimum of two images for image processing, this method requires only one fringe pattern for data extraction.
Original languageEnglish
Pages (from-to)317-324
Number of pages8
JournalOptics and Laser Technology
Issue number5
Publication statusPublished - 1 Jan 1998


  • Digital speckle pattern interferometry
  • Hilbert transformation
  • Quantitative vibration measurement
  • Time-average

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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