Method of detecting particles by detecting a variation in scattered radiation
First Claim
1. A method of detecting particles comprising the steps of:
- emitting a beam of radiation, wherein the beam has a path within a field of view of an image capturing device;
capturing images with the image capturing device, wherein an area in the images contains the path of a beam of radiation;
determining an integration region in the images, being the area in the images containing the path;
determining background regions in the images, being the areas on either side of the integration region;
compensating for variation in illumination levels in the integration region based on illumination levels in the background regions; and
detecting a variation in the images indicating an increase in scattered radiation in the integration region due to the presence of particles.
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Accused Products
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.
63 Citations
20 Claims
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1. A method of detecting particles comprising the steps of:
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emitting a beam of radiation, wherein the beam has a path within a field of view of an image capturing device; capturing images with the image capturing device, wherein an area in the images contains the path of a beam of radiation; determining an integration region in the images, being the area in the images containing the path; determining background regions in the images, being the areas on either side of the integration region; compensating for variation in illumination levels in the integration region based on illumination levels in the background regions; and detecting a variation in the images indicating an increase in scattered radiation in the integration region due to the presence of particles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of detecting particles comprising the steps of:
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emitting a beam of radiation, wherein the beam has a path within a field of view of an image capturing device; capturing images with the image capturing device, wherein an area in the images contains the path of a beam of radiation; compensating illumination levels in the images, based on illumination levels in the images outside of said area; and detecting a variation in the images indicating an increase in scattered radiation from the beam due to the presence of particles. - View Dependent Claims (17, 18, 19, 20)
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Specification