Page 403 - Introduction to Information Optics

388 7. Pattern Recognition with Optics

Fig. 7.29. (a) Out-of-plane rotation training images: M60 tanks and T72 tanks, (b) A bipolar
composite filter to detect a T72 tank.

7.5.1. PERFORMANCE CAPACITY

2
Strictly speaking, an n x n pixel array bipolar spatial filter has 2" images.
However, in practice, a bipolar spatial filter may not memorize such a great
number of training images. The reality is that some of the pixel elements would
not be utilized in the synthesis. Thus, the actual capacity of a composite filter
is to accommodate the largest possible number of training images, by which
the effective pixels are efficiently used.
To look at the performance capacity of a composite filter, we focus our
attention on correlation peak intensity detection. By setting the traditional
3 dB criterion, the performance capacity of SABCF can be defined as given by:

Q 5It
PC (number of training images) = minimum of <J^ arget ^ - "*«-™*
DR ^ 1.3,
(7.32)