Showing papers on "Intrusion detection system published in 1972"
Patent•
29 Dec 1972
TL;DR: In this paper, a security system for the detection of moving targets such as intruders and also of fire and explosions was proposed. But the system was not designed for indoor environments.
Abstract: A security system for the detection of moving targets such as intruders and also of fire and explosions. A plurality of sensors such as photoelectric cells or infrared detectors are focused in an inner and outer pattern, such as pairs of nearly coaxial cones, of different slope, for example, to create inner and outer zones of intrusion. The outputs from the sensors are coupled through a sequencing unit which is programmed to yield an output only when intrusion into the inner zone follows intrusion into the outer zone no more quickly than after a predetermined time delay. A fire detection system places sensors in an area to be protected, utilizing the same general type of operation as the intruder protection with some differences. A plurality of lockout sensors sensing ambient light conditions to lockout the sequencing units of the intrusion detection system and fire detection system if the changes are due to changes in the ambient light.
24 citations
Patent•
08 Dec 1972
TL;DR: In this article, an electromagnetic intrusion detection system employs changes in the amplitude and/or phase of energy returned from objects in a zone under surveillance to indicate the introduction of a target.
Abstract: An electromagnetic intrusion detection system employs changes in the amplitude and/or phase of energy returned from objects in a zone under surveillance to indicate the introduction of a target. An electromagnetic field is provided in the protected zone and sensed by a receiver which includes a processor operative to provide signals representative of the position of objects in the protected zone. A net change in the position of an object or the introduction of an intruder causes a sensible change in the signals which is employed to activate an alarm.
16 citations
Patent•
27 Apr 1972
TL;DR: The disclosure relates to devices to detect intrusion of a small mass into a doorway or the like Detection is caused by interruption of a rapidly scanning or other appropriate light beam or radiation source which impinges upon a photovoltaic or photoconductive tape fastened to the perimeter of the doorway as mentioned in this paper.
Abstract: The disclosure relates to devices to detect intrusion of a small mass into a doorway or the like Detection is caused by interruption of a rapidly scanning or other appropriate light beam or radiation source which impinges upon a photovoltaic or photoconductive tape fastened to the perimeter of the doorway Interruption of the light beam or its equivalent causes a momentary reduction in current or voltage emitted by the tape
9 citations