# US 7,609,852 B2 · Early fire detection method and system based on image processing

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- Number: US 7,609,852 B2
- Document ID: US7609852B2
- Status: Granted
- Kind: B2
- Application number: 11/419,751
- Filed: 2006-05-22
- Published: 2006-09-21
- Granted: 2009-10-27
- Earliest claimed: 2004-11-16
- Assignees: Huper Laboratories Co., Ltd.
- Inventors: Chao-Ho Chen
- Web page: https://patentgrep.com/patent/US7609852B2

## CPC

- G08B 17/125: {by using a video camera to detect fire or smoke}
- G08B 29/186: {Fuzzy logic; neural networks}
- G08B: SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS

## Abstract

Fire detection and smoke detection use an image capturing device to obtain images from a predetermined area and adopt an RGB (red, green, blue) color model based chromatic and disorder measurement for extracting flame pixels and smoke pixels. The extracted pixels are inputted to a fire detection fuzzy alarm system to generate an output of alarm information. Based on iterative checking on the growing ratio of the alarm information, a fire alarm is released accordingly.

## Claims

### Claim 1

A flame detection method based on image processing comprising following steps:
(a) capturing images of a predetermined area by an image capturing device;
(b) detecting number of flame pixels of each image by determining if each pixel of each image satisfies the following conditions:
R>RT;
R≧G>B;
S≧((255−R)*ST/RT);
wherein R, G, B are red, green, blue gray levels of the pixel respectively, RT is a threshold of the red gray level, S is saturation of the pixel, and ST is saturation of the pixel when the red gray level of the pixel equals RT;
(c) generating a value according to the number of flame pixels of each image by a fuzzy system; and
(d) comparing values generated from images captured within a predetermined time interval to generate a comparison result.

### Claim 2 (depends on 1)

The method of claim 1 further comprising checking if a ratio of number of pixels around circumference of an object formed by flame pixels of the image and number of pixels of the object is greater than a disorder threshold.

### Claim 3 (depends on 1)

The method of claim 1 wherein step (d) comprises generating a comparison result when the flame-pixel quantities of images satisfies the following condition:
Mi+1>Mi for (R/N)>K;
where Mi+1 and Mi are the flame-pixel quantities of a next image and a current image respectively, N denotes the times of comparing Mi with Mi+1 at intervals of tR during a time period T, R denotes the times of Mi+1>Mi, and K is a number between 0 and 1 relying on statistical data experiments.

### Claim 4 (depends on 1)

The method of claim 1 wherein step (d) comprises generating a comparison result when the flame-pixel quantities of images satisfies the following condition:
((Mi+1−Mi)/Mi)>S;
where Mi+1 and Mi are the flame-pixel quantities of a next image frame and a current image frame respectively, and S denotes the growing rate of flames.

### Claim 5 (depends on 1)

The method of claim 1 further comprising releasing an alarm.

### Claim 6

A smoke detection method based on image processing comprising following steps:
(a) capturing images of a predetermined area by an image capturing device;
(b) detecting number of smoke pixels of each image;
(c) generating a value according to the number of smoke pixels of each image by a fuzzy system; and
(d) comparing values generated from images captured within a predetermined time interval to generate a comparison result when the smoke-pixel quantities of images satisfies the following condition:
Mi+1>Mi for (R/N)>K;
where Mi+1 and Mi are the smoke-pixel quantities of a next image and a current image respectively, N denotes the times of comparing Mi with Mi+1 at intervals of tR during a time period T, R denotes the times of Mi+1>Mi, and K is a number between 0 and 1 relying on statistical data experiments.

### Claim 7 (depends on 6)

The method of claim 6 wherein step (b) comprises updating the number of smoke pixels when red, green and blue gray levels of a pixel of the image are approximately equal, and intensity of the pixel is within a predetermined range.

### Claim 8 (depends on 6)

The method of claim 6 further comprising checking if a ratio of number of pixels around circumference of an object formed by smoke pixels of the image and number of pixels of the object is greater than a disorder threshold.

### Claim 9 (depends on 6)

The method of claim 6 further comprising releasing an alarm.

### Claim 10

A flame detection and smoke detection system based on image processing comprising:
an image capturing device for capturing images of a predetermined area;
means for detecting number of flame pixels and number of smoke pixels of each image captured by the image capturing device by determining if each pixel of each image satisfies the following conditions:
R>RT;
R≧G>B;
S≧((255−R)*ST/RT);
wherein R, G, B are red, green, blue gray levels of the pixel respectively, RT is a threshold of the red gray level, S is saturation of the pixel, and ST is saturation of the pixel when the red gray level of the pixel equals RT;
a fuzzy system for generating a value according to the number of flame pixels or the number of smoke pixels of each image; and
means for comparing values generated from images captured by the image capturing device within a predetermined time interval to generate a comparison result.

### Claim 11 (depends on 10)

The system of claim 10 further comprising means for detecting a moving object of the predetermined area.

### Claim 12 (depends on 11)

The system of claim 11 further comprising means for verifying the moving object as a real flame.

### Claim 13 (depends on 11)

The system of claim 11 further comprising means for verifying the moving object as a real smoke.

### Claim 14 (depends on 10)

The system of claim 10 further comprising means for outputting an alarm.

### Claim 15 (depends on 10)

The system of claim 10 wherein the image capturing device is a camera.

### Claim 16 (depends on 10)

The system of claim 10 wherein the image capturing device is a camcorder.