Optical pattern recognition architecture implementing the mean-square error correlation algorithm

Patent · Tue Jan 01 00:00:00 EST 1991

OSTI ID:868040

Molley, Perry A ^[1]

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1. Albuquerque, NM

An optical architecture implementing the mean-square error correlation algorithm, MSE=.SIGMA.[I-R].sup.2 for discriminating the presence of a reference image R in an input image scene I by computing the mean-square-error between a time-varying reference image signal s.sub.1 (t) and a time-varying input image signal s.sub.2 (t) includes a laser diode light source which is temporally modulated by a double-sideband suppressed-carrier source modulation signal I.sub.1 (t) having the form I.sub.1 (t)=A.sub.1 [1+.sqroot.2m.sub.1 s.sub.1 (t)cos (2.pi.f.sub.o t)] and the modulated light output from the laser diode source is diffracted by an acousto-optic deflector. The resultant intensity of the +1 diffracted order from the acousto-optic device is given by: I.sub.2 (t)=A.sub.2 [+2m.sub.2.sup.2 s.sub.2.sup.2 (t)-2.sqroot.2m.sub.2 (t) cos (2.pi.f.sub.o t] The time integration of the two signals I.sub.1 (t) and I.sub.2 (t) on the CCD deflector plane produces the result R(.tau.) of the mean-square error having the form: R(.tau.)=A.sub.1 A.sub.2 {[T]+[2m.sub.2.sup.2.multidot..intg.s.sub.2.sup.2 (t-.tau.)dt]-[2m.sub.1 m.sub.2 cos (2.tau.f.sub.o .tau.).multidot..intg.s.sub.1 (t)s.sub.2 (t-.tau.)dt]} where: s.sub.1 (t) is the signal input to the diode modulation source: s.sub.2 (t) is the signal input to the AOD modulation source; A.sub.1 is the light intensity; A.sub.2 is the diffraction efficiency; m.sub.1 and m.sub.2 are constants that determine the signal-to-bias ratio; f.sub.o is the frequency offset between the oscillator at f.sub.c and the modulation at f.sub.c +f.sub.o ; and a.sub.o and a.sub.1 are constant chosen to bias the diode source and the acousto-optic deflector into their respective linear operating regions so that the diode source exhibits a linear intensity characteristic and the AOD exhibits a linear amplitude characteristic.

• Research Organization: AT&T
• DOE Contract Number: AC04-76DP00789
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 5060282
• OSTI ID: 868040
• Country of Publication: United States
• Language: English

Related Subjects

optical
pattern
recognition
architecture
implementing
mean-square
error
correlation
algorithm
sigma
i-r
discriminating
presence
reference
image
input
scene
computing
mean-square-error
time-varying
signal
laser
diode
light
source
temporally
modulated
double-sideband
suppressed-carrier
modulation
form
sqroot
2m
cos
output
diffracted
acousto-optic
deflector
resultant
intensity
device
-2
time
integration
signals
ccd
plane
produces
result
tau
multidot
intg
t-
dt
aod
diffraction
efficiency
constants
determine
signal-to-bias
ratio
frequency
offset
oscillator
constant
chosen
bias
respective
linear
operating
regions
exhibits
characteristic
amplitude
reference image
signal input
modulation signal
image signal
pattern recognition
light source
laser diode
light intensity
light output
mean-square error
modulated light
time integration
optic device
linear intensity
diffraction efficiency
error correlation
frequency offset
optical pattern
amplitude characteristic
architecture implementing
correlation algorithm
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