Infrared intruder detection system
First Claim
1. An infrared intruder detection system comprising:
- a first means for sensing infrared radiation incident on a first location, said first infrared-sensing means producing either a positive or negative output signal +A or -A in response to the infrared radiation sensed;
a second means for sensing infrared radiation incident on a second location spaced from the first location, said second infrared-sensing means producing either a positive or a negative output signal +B or -B in response to the infrared radiation sensed; and
sequence detection means for receiving the output signals from the first and second means for sensing infrared radiation, and for producing an alarm output indicating the presence of an intruder when an output signal sequence of +A followed by +A and +B, followed by +B is detected, or when an output signal sequence of -A, followed by -A and -B, followed by -B is detected.
1 Assignment
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Accused Products
Abstract
An infrared intruder detection system has two separate channels A and B. Each channel has its own pyroelectric detector device and threshold level comparator. The comparator is responsive to dual polarity pyroelectric voltage outputs produced by the associated detector device as a result of an intruder-related infrared image moving thereacross. A logic circuit analyzes the comparator outputs and responds to the identification of particular intruder-indicative sequences of comparator outputs in both channels to generate an alarm and/or switching output. The logic circuit may also identify shock-induced comparator outputs. The system offers a high intruder detection capability with immunity from false triggering.
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Citations
11 Claims
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1. An infrared intruder detection system comprising:
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a first means for sensing infrared radiation incident on a first location, said first infrared-sensing means producing either a positive or negative output signal +A or -A in response to the infrared radiation sensed; a second means for sensing infrared radiation incident on a second location spaced from the first location, said second infrared-sensing means producing either a positive or a negative output signal +B or -B in response to the infrared radiation sensed; and sequence detection means for receiving the output signals from the first and second means for sensing infrared radiation, and for producing an alarm output indicating the presence of an intruder when an output signal sequence of +A followed by +A and +B, followed by +B is detected, or when an output signal sequence of -A, followed by -A and -B, followed by -B is detected. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification