High Resolution Phase-stepping Shearography by a Using 24 Megapixel Digital Still Imaging Device

Awatef Rashid Al Jabri*, Kazi Monowar Abedin, S. M.Mujibur Rahman

*Corresponding author for this work

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


Digital phase-stepping shearography is a modern precision measurement technique for quantifying microscopic displacement gradients and strains of an object surface by interferometric speckle techniques. The phase map of the displacement derivatives of a stressed object is generated using laser speckles in this technique. As a result, the strains of a deformed object can be directly mapped. Phase-stepping shearography is also very useful in industrial non-destructive testing (NDT). In conventional digital phase stepping shearography, a video camera of limited resolution is used for imaging the laser speckles. The maximum resolution of the video camera is only of the order of 5 Megapixels. This limits the spatial resolution for the generated shearograms and phase maps, and consequently, limits the maximum value of the deformations that can be successfully observed in a given situation. We improved the shearography technique and, in particular, performed advanced shearographic experiments with substantially higher spatial resolution than is now achievable. A 24 megapixel still digital image device (DSLR camera) and a Michelson-type shearing setup with an edge-clamped, center-loaded plate are used in this novel technique. Different phase-stepping algorithms were tested, and all of them produced shearograms satisfactory quality. This effectively increases the useful spatial resolution of phase-stepping shearography by roughly 5 times compared to the conventional method using video-rate cameras, and will also improve spatial resolution in many possible applications.

Original languageEnglish
Title of host publicationQuantum Sensing, Imaging, and Precision Metrology
EditorsJacob Scheuer, Selim M. Shahriar
ISBN (Electronic)9781510659995
Publication statusPublished - 2023
Externally publishedYes
EventQuantum Sensing, Imaging, and Precision Metrology 2023 - San Francisco, United States
Duration: Jan 28 2023Feb 2 2023

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceQuantum Sensing, Imaging, and Precision Metrology 2023
Country/TerritoryUnited States
CitySan Francisco


  • digital shearography
  • high-resolution digital imaging device
  • phase-stepping techniques
  • precision metrology

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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