
where J
1
(x) is the first-order Bessel function of the first kind [4]. The intensity
distribution associated with this psf is called the Airy disk pattern, after G.B. Airy
[9, 10], and is shown in Fig. 2.2. The constant, r
o
, a dimensional scale factor, is
r
o
¼
ld
i
a
(2:10)
and r is radial distance measured from the origin of the image plane, that is,
r ¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
x
2
i
þ y
2
i
q
(2:11)
2.4.2 The Optical Transfer Function
Since the imaging system in Fig. 2.1 is a shift-invariant linear system, it can be
specified either by its impulse response (i.e., the psf ) or by the Fourier transform
of its psf, which is called the optical transfer function (OTF). For a lens ...