Page 441 - Introduction to Information Optics

426 7. Pattern Recognition with Optics

(d) If the focal length of these lenses is 50 mm, compute the required
2
diameter of the lenses to match an input pattern of 2 x 2 cm .
(e) Assuming that the diffraction angle of the diffuser is 18°, and the
transmittance of the LCTVs is 10 percent, estimate the power budget
of the ONN.
7.12 Refer to the misalignment limitations for the VLC and JTC as discussed
in Sec. 7.1.4.
(a) Evaluate the transversal (filter) tolerance for these correlators.
(b) Sketch the correlation performance as a function of shifted filter
plane.
7.13 Write an implicit correlation-detection equation as function of longitudi-
nal misalignment for the VLC and JTC, respectively. Sketch the correla-
tion performances for these correlators.
7.14 Consider a quasi-Fourier transformer as shown in Fig. 7.61, in which h is
the width of an input object.
(a) Calculate the corresponding focal depth of the processor.
(b) Evaluate the allowable object displacement.
(c) Comment on your result.
7.15 Refer to the unconventional JTC of Fig. 7.62. Evaluate the allowable focal
depth 3 and incident angle 6, respectively, where b is the spatial width of
the input objects.
7.16 Besides the trivial advantages of improving detection efficiency and SLM
pixel utilization, show that the intrapattern correlations (which produce
false alarms) can be eliminated by a nonzero-order JTC.
7.17 Show that a nonzero order JTC can also be achieved by using phase-
shifting technique. In other words, by changing the sign of the reference
function, a nonzero-order JTPS can be obtained by subtraction. Compare
with the nonzero-order JTC in Sec. 7.2.2.

object function

Monochromatic
Plane Wave

reference function

Fig. 7.61.