Passive infrared detection system and method with adaptive threshold and adaptive sampling
US5870022A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1997 |
| Grant date | Feb 9, 1999 |
| Priority date | — |
| Expiry date | Sep 30, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/26
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A detection system and method are capable of reducing the occurrence of false alarms and detection failures by compensating for variations in the amplitude of a detection signal generated by a PIR sensor. An adaptive threshold can be used that varies according to ambient temperature of the detection area and the frequency of the detection signal. Comparison of the detection signal to the adaptive threshold allows compensation for temperature- and/or frequency-induced variations in detection signal amplitude. The adaptive threshold can be configured for standard detection area conditions or calibrated for conditions at the installation site. Relative measurement and adaptive sampling techniques also can be used to compensate for the presence of low frequency shifts in the detection signal. Such techniques can provide an accurate representation of signal amplitude relative to a threshold amplitude despite differences in absolute signal magnitude. The use of an adaptive sampling rate that increases with the onset of a potential intruder event contributes to power conservation in the detector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.