Projection-type moiré contouring can be done without a reference grid by
undersampling projected cosine fringes with a charged-coupled-device detector
array to eliminate entirely the unwanted sum, shadow, and grid terms of
classical moiré methods as well as the spurious moiré fringes
that are due to higher harmonics. The technique produces a high-visibility
sampled version of the moiré difference contour fringes. Higher-order
aliasing can provide increased sensitivity when the same detector array is used.
The sampling conditions are formulated as a moiré extension to the
Whittaker–Shannon sampling theorem.
© 1984 Optical Society of America
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