Page 104 - Introduction to Information Optics

2.5. Image Processing with Optics 89
SLM,
A CCO,
I \-**d3—-t

Fig. 2.18. A microcomputer-based JTP.

and the reference function can be obtained at the back focal plane of the
Fourier transform lens L 3. Once again we see that a real-time hybrid optical
processor can be constructed using the joint transform architecture.

2.5. IMAGE PROCESSING WITH OPTICS

The discovery of laser has prompted us to build more efficient optical
systems for communication and signal processing. Most of the optical process-
ing to date has been confined to either complete coherence or complete
incoherence. However, a continuous transition between these two extremes is
possible, as will be discussed later. In this section we examine a few applica-
tions under the coherent regime.

2.5.1. CORRELATION DETECTION

Let us consider the Fourier domain processor (FDP) of Fig. 2.17, in which
an input object /(x, y) is displayed at the input plane, the output complex light
can be shown as
y) * h(x, >'), (2.46)