A method for direct shape measurement with short laser light pulses
and digital holography with a CCD array is proposed. An in-line
holographic setup is used in which the reference beam is reflected from
a blazed reflection grating, i.e., a Littrow setup. By this method
a relatively large optical delay is created between the reference and
the object beams even with a small object–reference angle, which is
necessary because of the limited resolution of the CCD. The delay
varies continuously across one axis of the CCD array. In this way
different object sections are reconstructed from different parts of the
CCD, which in turn correspond to a certain path length from the
object. By putting the sections together, one can evaluate the
three-dimensional shape. Theoretical as well as experimental
results are presented.
© 1998 Optical Society of America
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