Additive-subtractive phase-modulated electronic speckle interferometry: Analysis of fringe visibility

Bruno F. Pouet, Sridhar Krishnaswamy

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Fringe-visibility issues of additive-subtractive phase-modulated (ASPM) electronic speckle pattern interferometry (ESPI) are explored. ASPM ESPI is a three-step method in which additive-speckle images are acquired rapidly in an analog fashion in every frame of a video sequence, a speckle phase modulation is intentionally introduced between frames, and a digital subtraction of consecutive pairs of additive-speckle images is performed. We show that this scheme has the good high-frequency noise immunity associated with additive-ESPI techniques as well as the good fringe visibility associated with subtractive-ESPI techniques. The method has better fringe visibility than can be obtained with purely additive ESPI and also does not suffer from the fringe distortions that can occur with subtractive ESPI in the presence of high-frequency noise. We show that even if full speckle decorrelation were to occur between the two additive speckle images that are to be subtracted, the visibility of ASPM ESPI fringes can be made to approach unity by suitable adjustment of the reference-to-object beam-intensity ratio.

Original languageEnglish (US)
Pages (from-to)6609-6616
Number of pages8
JournalApplied Optics
Volume33
Issue number28
DOIs
StatePublished - Oct 1 1994

Keywords

  • Additive-subtractive phase-modulation ESPI
  • Fringe visibility
  • Optical and electronic noise
  • Speckle decorrelation

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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