Passive infrared intrusion detector employing correlation analysis
US4746910A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 1986 |
| Grant date | May 24, 1988 |
| Priority date | — |
| Expiry date | Oct 3, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S250/01
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
For reducing the susceptibility to false alarms and for increasing the detection probability of a passive infrared detector, the actual signals obtained from a first sensor element are continuously compared in a correlator with reference or set signals stored in a read-only memory and/or with the actual signals obtained from a second sensor element monitoring the near region. The correlator delivers an output signal which corresponds to the correlation of both signals which are compared with one another. An alarm signal is triggered when the correlation exceeds a predetermined value, for instance 0.7, and the amplitude has reached a predetermined threshold. The infrared detector affords high security against giving of false alarms and a high detection probability, even in the presence of signals possessing a great amount of noise, but also delivers an alarm signal in the event the detector is attempted to be sabotaged, for instance by covering the inlet optical system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.