Directional people counting arrangement
US4799243A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 1, 1987 |
| Grant date | Jan 17, 1989 |
| Priority date | — |
| Expiry date | Sep 1, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S250/01
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An arrangement for detecting the passage of living beings through a surveillance region into and out of a controlled-access space includes at least one pyroelectric detector device that includes two detector elements which have active areas that are directly exposed to thermal radiation from the surveillance region and convert the thermal radiation energy received thereby into electrical signals with opposite polaritites. The detector elements are situated in succession in the direction of passage into the controlled-access space. The surveillance region is optically subdivided into two surveillance zones arranged in succession as considered in the passage direction, for instance by a mask that masks an intervening zone situated between the surveillance zones to prevent thermal radiation from the intervening zone from reaching either one of the detector elements. Thus, the thermal radiation energy from a living being passing through the surveillance region reaches initially only one and subsequently only the other of the detector elements when such living being is entering, and initially only the other and subsequently only the one detector element when such living being is leaving…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.