Oblique incidence reflectometry: Optical models and measurements using a side-viewing gradient index lens-based endoscopic imaging system

R. Andrew Wall, Jennifer K. Barton

Research output: Contribution to journalArticle

3 Scopus citations


A side-viewing, 2.3-mm diameter oblique incidence reflectometry endoscope has been designed to obtain optical property measurements of turbid samples. Light from a single-mode fiber is relayed obliquely onto the tissue with a gradient index lens-based distal optics assembly and the resulting diffuse reflectance profile is imaged and collected with a 30,000 element, 0.72 mm clear aperture fiber bundle. Sampling the diffuse reflectance in two-dimensions allows for fitting of the reflected intensity profile to a well-known theoretical model, permitting the extraction of both absorption and reduced scattering coefficients of the tissue sample. Models and measurements of the endoscopic imaging system are presented in tissue phantoms and in vivo mouse colon, verifying the endoscope's capabilities to accurately measure effective attenuation coefficient and differentiate diseased from normal colon.

Original languageEnglish (US)
Article number067002
JournalJournal of biomedical optics
Issue number6
StatePublished - Jun 2014



  • absorption coefficient
  • colon.
  • endoscope
  • gastrointestinal
  • gradient-index
  • oblique incidence reflectometry
  • reduced scattering coefficient
  • tissue optical properties

ASJC Scopus subject areas

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

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