The phase-shifting technique is used in optical metrology to
evaluate the local phase of a fringe pattern. Accurate calibration
of the shifting device is often essential but sometimes hardly possible
because of deviations of the fringe pattern from the ideal sinusoidal
shape and because of a nonconstant phase shift between consecutive
frames. We introduce a new technique for calculating the phase
shift between frames even in the presence of high noise and
nonsinusoidal fringe patterns. In addition, this technique permits
the identification of different error sources such as low
signal-to-noise ratio, higher harmonics contained in the fringe
pattern, and nonconstant phase shift.
© 1998 Optical Society of America
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