Page 118 - Introduction to Information Optics
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2.6. Algorithms for Processing 103
frequency
locus
10: P
Fig. 2.29. Output frequency locus.
To conclude this section, we note that one interesting application of optical
processing of broadband signals is its application to synthetic aperture radar.
A broadband microwave signal is first converted in two-dimensional raster-
scanned format, similar to the preceding example. If the raster-scanned format
is presented at the input plane of a specially designed optical processor, an
optical radar image can be observed at the output plane.
2.6. ALGORITHMS FOR PROCESSING
In the preceding we have addressed techniques that rely on linear spatial
invariant operation, for which the output response of the processor can be derived
from the input object function as it convolves with the spatial impulse response of
the filter. There are several inherent constraints of the preceding processors, such
as scale and rotational variants, nonlinearity operation, and others. We now discuss
a few algorithms that can be used to alleviate some of those drawbacks.
