Smoke and flame detection

• US 20030141980A1
• Filed: 01/03/2003
• Published: 07/31/2003
• Est. Priority Date: 02/07/2000
• Status: Active Grant

• Current Assignee: VSD Limited
• Original Assignee: VSD Limited
• Inventors: Colby, Edward Grellier, Moore, Ian Frederick, Black, Michael John
• Granted Patent: US 7,002,478 B2
• Time in Patent Office: Days
• US Class Current: 340/578
• CPC Class Codes: G08B 17/125 by using a video camera to detect fire or smoke

Abstract

A method of operating a computer for smoke and flame detection comprising the steps of: receiving digitised images of the region to be monitored; comparing pixels of one of said images with pixels of another said image according to two predetermined procedures to produce a flame present decision and a smoke present decision; and providing a fire detected signal according to said smoke present and flame present decisions.

Claims

1. A combined flame and smoke detection system comprising means for producing a digital image of a detection region, smoke and flame detection processing means operable to process at least two said digital images and generate an output signal according to the data generated in the process.

3. A system as claimed in claim 1, wherein said processor is arranged to generate an output signal indicating the detection of smoke, flame detected or smoke and flame detected and said data comprises a flame detected indicator and a smoke detected indicator.

4. A system as claimed in claim 1, 2 or 3, wherein said processor processes successive said digital images.

6. A system as claimed in any one of the preceding claims, further comprising means for producing a visual display in accordance with said output signal.

7. A system as claimed in any one of the preceding claims, further comprising means for producing an alarm signal in accordance with said output signal.

19. A computer program carrier having thereon code portions which when loaded and run on computer means cause the computer means to constitute the system according to any one of claims 1 to 7.

2. A combined flame and smoke detection system utilising a processor to process digital images of a detection region generated from images captured by a camera in accordance with a flame detection routine and a smoke detection routine to detect smoke and flame, said processor being arranged to provide a signal indicative of smoke detected, flame detected or smoke and flame detected according to the respective outputs of said routines.

5. A combined smoke and flame detection system comprising at least one video camera, a video frame comparator and a processor, wherein said processor is arranged to analyse successive frames captured by the or each said camera by comparing individual pixels thereof to detect the presence of smoke and flame, said processor analysing said successive frames according to at least two predefined relationships so as to be capable of detecting smoke and flame and generating an output signal indicating the presence of smoke, flame, or smoke and flame.

8. A method of detecting smoke and flame, the method comprising the steps of:

receiving digitised images of a region to be monitored;

comparing pixels of one of said images with pixels of another said image according to two predetermined procedures to produce a flame present decision and a smoke present decision; and

providing a fire detected signal according to said smoke present and flame present decisions.

10. A method as claimed in claim 8 or claim 9 in which the pixels of successive images are compared.

11. A method as claimed in any one of claims 8 to 10, wherein one said predetermined procedure produces a flame present decision and comprises the step of filtering said digitised images such that only changes in pixel characteristics occurring within a predetermined frequency band are used to produce said flame present decision.

12. A method as claimed in claim 11, wherein said filtering step comprises filtering out changes in pixel characteristics occurring in the frequency band 1.25 to 4 Hz.

13. A method as claimed in claim 11 or claim 12, wherein said one procedure includes the step of determining the density of changes in pixel characteristics and determining the presence of a flame if a density in excess of a predetermined density value is determined.

14. A method as claimed in any one of claims 8 to 13, wherein said fire detected signal is produced in accordance with a weighted analysis of said flame present decision and said smoke present decision.

15. A method as claimed in any one of claims 8 to 13, wherein said fire detected signal is produced in accordance with a vote based analysis of said flame present decision and said smoke present decision.

18. A computer program carrier having thereon code portions which when loaded and run on computer means cause the computer means to execute the method of any one of claims 8 to 17.

9. A method of detecting smoke and flame, the method comprising the steps of:

producing digitised images of a region to be monitored;

comparing pixels of one of said images with pixels of another said image according to two predetermined procedures to produce a flame present decision and a smoke present decision; and

providing a fire detected signal according to said smoke present and flame present decisions.

16. A method of operating a computer for smoke and flame detection comprising the steps of:

receiving digitised images of a region to be monitored;

comparing pixels of one of said images with pixels of another said image according to two predetermined procedures to produce a flame present decision and a smoke present decision; and

providing a fire detected signal according to said smoke present and flame present decisions.

17. A method of detecting fire, the method comprising the steps of:

receiving digitised images of a region to be monitored;

comparing pixels of one of said images with pixels of another said image according to a flame detection procedure to produce at least one flame detection indicia;

comparing pixels of one of said images with pixels of another said image according to a smoke detection procedure to produce at least one smoke detection indicia; and

using the flame detection indicia and the smoke detection indicia to determine and generate a fire detected signal.