The quantitative analysis of optical phase measurement and its application to the determination of corneal birefringence
Si, Chen (2011) The quantitative analysis of optical phase measurement and its application to the determination of corneal birefringence. PhD thesis, University of Warwick.
WRAP_THESIS_Si_2011.pdf - Submitted Version - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Official URL: http://webcat.warwick.ac.uk/record=b2533321~S1
In this thesis, a phase sensitive interferometer is successfully implemented to perform
birefringent object surface-profile measurement, based on a polarisation adjustment
approach. Using monochromatic light, a novel polarization interferometric
method is developed, incorporating the birefringence technique and a waveplate.
In our experiments, a birefringent wedge is designed for generating carrier
fringes in the polariscope. Retardance is calculated from phase shifting using a
phase matching technique. The accuracy of the method has been demonstrated
to have an error of less than 0.02 radians. The accuracy and resolution quantitative
analysis presented in this thesis can be used to determine accurately the
phase-shifting interferometry for high-precision surface profile and bio-structure,
such as fibre and collagen measurements with low cost.
FFT technique and phase-stepping methods are described to determine birefringence
within the cornea. The distribution of human corneal lamellar collagen is
determined through a microscopic technique using the combination of a circular
polariser and a quarter-wave retarder. A quantitative measure of corneal birefringence
is achieved by phase unwrapping. The experimental findings of elliptic and
hyperbolic populations of collagen fibrils may explain the optical phenomena of
central corneal retardation with biaxial-like behaviour in more peripheral areas.
A low cost, simple, and direct approach has been developed to make the required
microscopic measurement. The traditional transmission system is improved by
applying a reflection system with an LED light source and is suitable for the
analysis of the birefringent cornea structures in vivo.
A further instrument based upon a synthetic aperture approach has been created
with the purpose of measuring the three dimensional birefringence structure of the
cornea. The concept of the instrument is a combination of the parallax between
individual lenses and the numerically generated planes of focus to visualise the
|Item Type:||Thesis or Dissertation (PhD)|
|Subjects:||Q Science > QC Physics
Q Science > QM Human anatomy
|Library of Congress Subject Headings (LCSH):||Interferometers, Refraction, Double, Cornea -- Analysis, Biological interfaces|
|Official Date:||February 2011|
|Institution:||University of Warwick|
|Theses Department:||School of Engineering|
|Extent:||xxv, 294 leaves : ill., charts|
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