Passive infrared intrusion detection system
First Claim
1. A passive infrared intrusion detection system comprising:
- a multi-faceted parabolic reflector which views a target monitored area as a plurality of optically divided detection zones, said reflector collecting infrared rays emitted from an object within the monitored area;
a passive infrared intrusion detector means combined with said reflector for detecting the collected infrared rays;
comparison means for comparing values of signals outputted by said intrusion detector means with a reference value;
pulse discriminator means connected to said comparison means for passing only pulses of said comparison means having a pulse width exceeding a predetermined pulse width so as to eliminate narrow noise pulses; and
an alarm generating means including a counter for counting pulses outputted by said pulse discriminator means, and coincidence circuit means for generating an alarm signal only when the number of pulses received by said counter in a predetermined time interval exceeds a preset value.
1 Assignment
0 Petitions
Accused Products
Abstract
A passive infrared intrusion detector has:
a multi-faceted parabolic reflector for dividing a target controlled area into a plurality of optically divided detection zones, for collecting infrared rays emitted from an object within the controlled area;
a passive infrared intrusion sensor combined with the reflector to detect the collected infrared rays;
a first means for generating a pulse when an absolute value of an output of the passive intrusion sensor exceeds a reference value; and
a second means for generating an alarm signal when predetermined pulses are received from the first means within a predetermined period.
A pulse width discriminator is used to eliminate narrow noise pulses.
-
Citations
9 Claims
-
1. A passive infrared intrusion detection system comprising:
-
a multi-faceted parabolic reflector which views a target monitored area as a plurality of optically divided detection zones, said reflector collecting infrared rays emitted from an object within the monitored area; a passive infrared intrusion detector means combined with said reflector for detecting the collected infrared rays; comparison means for comparing values of signals outputted by said intrusion detector means with a reference value; pulse discriminator means connected to said comparison means for passing only pulses of said comparison means having a pulse width exceeding a predetermined pulse width so as to eliminate narrow noise pulses; and an alarm generating means including a counter for counting pulses outputted by said pulse discriminator means, and coincidence circuit means for generating an alarm signal only when the number of pulses received by said counter in a predetermined time interval exceeds a preset value. - View Dependent Claims (2, 3, 5, 6, 7, 8)
-
-
4. A passive infrared intrusion detection system comprising:
-
a multi-faceted parabolic reflector which views a target monitored area as a plurality of optically divided detection zones, said reflector collecting infrared rays emitted from an object within the monitored area; a passive infrared intrusion detector means combined with said reflector for detecting the collected infrared rays; first means for generating a pulse when a value of an output of said detector means exceeds a reference value; second means for generating an alarm signal in response to a predetermined number of pulses from said first generating means within a predetermined pierod; and a pulse discriminator interconnecting said first generating means with said second generating means for eliminating a noise pulse from pulses outputted from said first generating means, said noise pulse having a narrower pulse width than a predetermined pulse width, and wherein an output of said pulse discriminator is supplied to said second generating means.
-
-
9. A passive infrared intrusion detection system comprising:
-
a multi-faceted parabolic reflector which views a target monitored area as a plurality of optically divided detection zones, said reflector collecting infrared rays emitted from an object within the monitored area; passive infrared intrusion detector means combined with said reflector for detecting the collected infrared rays; first means for generating a pulse when a duration of an output of said detector means exceeds a predetermined pulse width so as to eliminate noise pulses; and second means for generating an alarm signal in response to a predetermined number of pulses from said first generating means within a predetermined period;
said second generating means comprising;counter means coupled to said first generating means for counting pulses outputted by said first generating means; and coincidence circuit means coupled to said counter means for generating an output as said alarm signal when a number of pulses from said first generating means exceeds a predetermined reference value.
-
Specification