Particle detection

• US 9,025,144 B2
• Filed: 11/14/2008
• Issued: 05/05/2015
• Est. Priority Date: 11/15/2007
• Status: Active Grant

• Current Assignee: Garrett Thermal Systems Ltd. (Honeywell International Inc.)
• Original Assignee: Xtralis Technologies Ltd (Honeywell International Inc.)
• Inventors: Knox, Ron, Ajay, Kemal, Boettger, Karl
• Primary Examiner(s): Ton, Tri T
• Application Number:
  US12/743,171
• Publication Number:
  US 20110058167A1
• Time in Patent Office: 2,363 Days
• Field of Search: 356337-343, 356/5.04, 356/5.03, 356432-438, 340/628, 340/630, 340/693.6, 348/148, 348/370, 386/227, 386/224, 382/218, 382/103
• US Class Current: 356/338
• CPC Class Codes: G01N 15/06 Investigating concentration of particle suspensions by weighing G01N5/00; investigating sedimentation of particle suspensions G01N15/04; investigating individual particles G01N15/10
• CPC Class Codes: G01N 15/075 by optical means
• CPC Class Codes: G01N 21/53 within a flowing fluid, e.g. smoke
• CPC Class Codes: G08B 17/125 by using a video camera to detect fire or smoke
• CPC Class Codes: G08B 29/18 Prevention or correction of operating errors G08B29/02, G08B29/12 take precedence
• CPC Class Codes: G08B 29/185 Signal analysis techniques for reducing or preventing false alarms or for enhancing the reliability of the system
• CPC Class Codes: H04N 5/32 Transforming X-rays cameras or camera modules for generating image signals from X-rays H04N23/30; circuitry of SSIS for transforming X-rays into image signals H04N25/30
• CPC Class Codes: H04N 7/18 Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast

Abstract

A particle detection system (100), such as an active video smoke detection system, includes at least one illumination means (102) for directing a beam (106) of radiation through at least part of the air volume being monitored (110), an image sensor (104) is positioned to capture images of at least part of a beam (106) from illumination means (102); and means to analyze (107) the captured images to detect the presence of particles within the volume. At least 29 different aspects are described for improving the sensitivity, usability, and robustness of particle detection. These include, for example, configuring illumination means (102) to create a curtain of light or a rapidly-scanned beam across the air volume (110), and configuring a reflector to steer or change direction of a beam reflected from illumination means (102).

Claims

1. A method of determining alignment of a beam in an AVSD system, the method including:

emitting a beam of light across a volume being monitored;

scanning the beam of light across a predetermined area;

receiving at least a portion of the beam of light at a light sensor; and

based on at least one measured parameter of the received light determining an alignment of the beam of light; and

based on the determined alignment, changing the alignment of the beam so that the beam is aligned in a predetermined manner.

2. A method as claimed in claim 1 wherein the measured parameter includes any one or more of the following characteristics:

light intensity, spot size, total received irradiance, a light intensity pattern.

3. A method as claimed in claim 1 wherein the method additionally includes:

reflecting at least a portion of the light beam from a reflector, back toward a light sensor such that either the emitted beam or reflected beam traverse the volume being monitored.

4. A method as claimed in claim 3 wherein the method includes the step of:

analysing the light received as a result of scanning of the beam to identify a light reception pattern characteristic of a reflection from a reflector forming part of the AVSD system.

5. A method as claimed in claim 4 wherein the optical characteristics of the reflector include means for forming a detectable pattern in light reflected from the reflector caused by a reflectivity, refraction and/or diffraction characteristic of at least part of the reflector.

6. A method as claimed in claim 1 wherein the step of scanning the beam of light across a predetermined area includes scanning the beam in a predetermined pattern.

7. A method as claimed in claim 6 wherein the pattern includes any one or more of the following patterns;

a linear patter, a raster pattern, a spiral pattern.