Electronic Speckle Pattern Interferometry (ESPI) dates from 1971.
Attempts at commercial exploitation were unsuccessful; at the
beginning of this decade it remained essentially a laboratory
technique. Problems arose from the practical operation of the
instrument and the nature of the output. Correlation fringes are
intrinsically noisy and their quality depends on many interrelated
factors. It is shown that by simplifying the optical design and
improving the quality of the optical components, the fringe contrast
is greatly improved and the instrument is made easier to use.
Extensions and improvements to the system are discussed: analogue
image processing techniques as a low cost means of improving the
appearance of the output; time invariant noise subtraction in time
averaged fringes gives similar quality results as that of the
subtraction mode; ensemble averaging of time variant noise is a new
technique for producing holographic quality results. Electronic
speckle contouring (ESC) gives a selection of methods for producing
programmable contour spacings and orientations for shape measurement.
ESPI is compared with other optical measurement techniques and is
shown to have fundamental advantages.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.