The purpose of this research is the quantitative investigation of
decorrelation-induced phase errors in speckle interferometry. Measurements in
speckle interferometry are inherently affected by decorrelation, i.e., by
alterations of the speckle fields during measurement. Likewise, the random
phases carrying the interferometric information change during decorrelation.
Image plane and pupil plane decorrelation are considered for both smooth and
speckle reference wave interferometers. Since the decorrelation effect depends
on the aperture and the pixel size, the calculations include not only the case
of speckles being well resolved by the camera but also the case of unresolved
speckles. Different standard deviations of the phase error are obtained from
the probability density of the pixel modulation and the phase before and after
decorrelation. Most cases (apart from pupil plane decorrelation in speckle
reference wave setups) appear to obey exactly the same phase error statistics.
In particular, the number of speckles per pixel does not affect the phase
error distribution over the whole image. The only important parameters
determining the decorrelation-induced phase errors are the amount of
decorrelation and the pixel modulation.
© 1997 Optical Society of America
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