Additive-subtractive speckle interferometry: Phase measurements in noisy conditions

Liusheng Wang, Sriclhar Krishnaswamy

Research output: Contribution to journalConference articlepeer-review

1 Scopus citations


In this paper we propose a novel technique for quantitative phase measurements of vibrating structures based on additive-subtractive speckle interferometry. Additive fringe patterns (of poor visibility) corresponding to the object deformation are obtained by pulsing the laser illumination at times when the deformation is at its maximum and minimum amplitudes. A relative inter-pulse phase shift is introduced within each repetitive deformation cycle (e.g. +π/2 for the maximum and-π/2 for the minimum amplitudes respectively) to obtain two consecutive conjugate pairs of phase-shifted additive fringe patterns. Additionally, an inter-frame phase shift is iniroduced between the conjugate pairs of additive fringe patterns, which are then subtracted and rectified to provide a phase-shifted additivesubtractive fringe pattern of good visibility. Typically four such phase-shifted additive-subtractive fringe patterns with relative phase shift of π/2 between each other are obtained, and these are used to calculate the deformation phase map from which the vibration deformation amplitudes can be readily obtained. Results have been obtained for the vibration measurement of a circular membrane. The ability of the technique to perform in relatively severe noisy environments is demonstrated.

Original languageEnglish (US)
Pages (from-to)384-393
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Jun 23 1995
EventInterferometry VII: Applications 1995 - San Diego, United States
Duration: Jul 9 1995Jul 14 1995


  • Additive-subtractive fringes
  • Laser strobing/pulsing
  • Measurements in noisy environments
  • Phase measurement technique
  • Speckle pattern interferometry

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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