EARLY FIRE DETECTION METHOD AND SYSTEM BASED ON IMAGE PROCESSING

• US 20060209184A1
• Filed: 05/22/2006
• Published: 09/21/2006
• Est. Priority Date: 11/16/2004
• Status: Active Grant

• Current Assignee: Huper Laboratories Co., Ltd.
• Original Assignee: Huper Laboratories Co., Ltd.
• Inventors: Chen, Chao-Ho
• Granted Patent: US 7,609,852 B2
• Time in Patent Office: Days
• US Class Current: 348/61
• CPC Class Codes: G08B 17/125 by using a video camera to detect fire or smoke
• CPC Class Codes: G08B 29/186 Fuzzy logic; neural networks

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

1. A flame detection method based on image processing comprising following steps:

(a) capturing images of a predetermined area;

(b) detecting number of flame pixels of each image;

(c) generating a value according to the number of flame pixels of each image; and

(d) comparing values generated from images captured within a predetermined time interval to generate a comparison result.

2. The method of claim 1 wherein step (b) comprises updating the number of flame pixels when a pixel of the image satisfies the following conditions:

R>

R_T;

R≧

G>

B; and

S≧

((255−

R)*S_T/R_T);

wherein R, G, B are red, green, blue gray levels of the pixel respectively, R_T is a threshold of the red gray level, S is saturation of the pixel, and S_T is saturation of the pixel when the red gray level of the pixel equals R_T.

3. The method of claim 1 wherein step (b) comprises updating the number of flame pixels when a pixel of the image satisfies the following conditions:

R>

R_T;

R≧

G>

B;

S≧

((255−

R)*S_T/R_T); and

I>

I_T;

wherein R, G, B are red, green, blue gray levels of the pixel respectively, R_T is a threshold of the red gray level, S is saturation of the pixel, S_T is saturation of the pixel when the red gray level of the pixel equals R_T, I is intensity of the pixel, and IT is a threshold of the intensity of the pixel.

4. 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.

5. The method of claim 1 wherein step (d) comprises generating a comparison result when the flame-pixel quantities of images satisfies the following condition:

M_i+1>

M_i for (R/N)>

K;

where M_i+1 and M_i are the flame-pixel quantities of a next image and a current image respectively, N denotes the times of comparing M_i with M_i+1 at intervals of t_R during a time period T, R denotes the times of M_i+1>

M_i, and K is a number between 0 and 1 relying on statistical data experiments.

6. The method of claim 1 wherein step (d) comprises generating a comparison result when the flame-pixel quantities of images satisfies the following condition:

((M_i+1−

M_i)/M_i)>

S;

where M_i+1 and M_i are the flame-pixel quantities of a next image frame and a current image frame respectively, and S denotes the growing rate of flames.

7. The method of claim 1 further comprising releasing an alarm.

8. A smoke detection method based on image processing comprising following steps:

(a) capturing images of a predetermined area;

(b) detecting number of smoke pixels of each image;

(c) generating a value according to the number of smoke pixels of each image; and

(d) comparing values generated from images captured within a predetermined time interval to generate a comparison result.

9. The method of claim 8 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.

10. The method of claim 8 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.

11. The method of claim 8 wherein step (d) comprises generating a comparison result when the smoke-pixel quantities of images satisfies the following condition:

M_i+1>

M_i for (R/N)>

K;

where M_i+1 and M_i are the smoke-pixel quantities of a next image and a current image respectively, N denotes the times of comparing M_i with M_i+1 at intervals of t_R during a time period T, R denotes the times of M_i+1>

M_i, and K is a number between 0 and 1 relying on statistical data experiments.

12. The method of claim 8 further comprising releasing an alarm.

13. 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;

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.

14. The system of claim 13 further comprising means for detecting a moving object of the predetermined area.

15. The system of claim 14 further comprising means for verifying the moving object as a real flame.

16. The system of claim 14 further comprising means for verifying the moving object as a real smoke.

17. The system of claim 13 further comprising means for outputting an alarm.

18. The system of claim 13 wherein the image capturing device is a camera.

19. The system of claim 13 wherein the image capturing device is a camcorder.