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In-Depth Information
Fig. 1.
System diagram of HIS
L
Imaging convergent lens (typically circular).
R
Planar sensing arrays, parallel with L, with a receptors' density function
ρ(x, y)
O
Optical center of
L
.
A
Main optical axis of the system, vertical to
L
and
R
with
A
passing through
O
and
OR
.
D
Diameter of
L
.
d
Distance between
L
and
R
.
T
Exposure time of the system.
HIS strongly focuses on the fundamental features of imaging and sensing proce-
dure of human eyes. The working principle of HIS can be divided into imaging pro-
cedure and sampling procedure. In imaging procedure, beam from the outside world
is converged by L when passing to generate a clear image on planar sensing arrays. In
sampling procedure, after exposure time T, each receptor on the plane transforms the
luminous energy cast on it to independently output a pixel in electronic signal and all
of these pixels together compose an image output.
3
Inferring of Resolving Power for HIS
3.1
Criteria and Definition of ARP for HIS
The ability of imaging system to distinguish two object points is called the system's
point resolving power (PRP). The minimum resolution angle, the minimum flair angle
of two object points relative to the system when distinguishable, is often employed as
the measurement of PRP and in this occasion, PRP is called angle resolving power
(ARP).
According to nature of electromagnetic wave, accompanied with geometric optics
are effects of wave optics, in which diffraction is a significant one. The diffraction
causes image of a single object point on sensing plane to be a vague spot, Airy disk,
with Airy disk's center as the ideal geometry image point. It is widely accepted that
the necessary and sufficient conditions for two spots to be distinguished by an optical
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