Page 442 - Introduction to Information Optics

Exercises 427
Beam Splitter
Collimated
laser Light

Square Law
Detector
Fig. 7.62.

7.18 (a) State the advantages of using a nonzero-order JTC as compared with
the conventional JTC.
(b) What is the price paid to gain these advantages?
7.19 Pattern discriminability is probably one of the most important criterion
used for optical pattern recognition, which is defined by the signal-to-
clutter ratio as given by

API
SCR
CPI

where API is the autocorrelation peak intensity and CPI is the maximum
cross-correlation peak intensity. Show that phase-encoded JTC can
indeed improve the SCR (i.e., SCR > 1).
7.20 Most of the SLMs are amplitude-modulated devices. To improve the
performance of pattern detection, one may use the position-encoded JTC.
Illustrate that the position-encoded JTC can indeed improve pattern
discriminability.
7.21 One of the major advantages of using a hybrid JTC is adaptivity, by
which iterative processing can be performed. Conventional JTC suffers
strong background noise, which produces low diffraction efficiency. We
assume two targets are embedded in random bright background terrain,
which produces poor correlation peak intensities at the output plane.
Show that higher correlation peak intensities can be produced by con-
tinuous JTC-iterative processing.