Method of detecting particles by detecting a variation in scattered radiation
US7983445B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 14, 2004 |
| Grant date | Jul 19, 2011 |
| Priority date | — |
| Expiry date | Dec 31, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A smoke detecting method which uses a beam of radiation such as a laser (16), to monitor a region, such as a room (12). A camera (14) is used to capture images of part of the room (12), including a path of the laser beam. Particles in the laser beam scatter light (30), and this is captured by the camera (14) for analysis. A processor (20) extracts data relating to the scattered light (30) to determine the density of particles in the beam, to determine the level of smoke in the region. The laser may have a modulated output (38) so that images captured without the laser tuned “on” can be used as a reference point and compared to images taken with the laser turned “on”, to assist in determining the level of scattered light (30) compared to ambient light. Filters (24, 26) may be used to decrease signals generated from background light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.