Early fire detection method and system based on image processing

• US 7,609,852 B2
• Filed: 05/22/2006
• Issued: 10/27/2009
• 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
• Primary Examiner(s): AZARIAN, SEYED H
• Application Number:
  US11/419,751
• Publication Number:
  US 20060209184A1
• Time in Patent Office: 1,254 Days
• Field of Search: 382/100, 382/103, 382/106, 382/107, 382/154, 382/155, 382/162, 382/165, 382/167, 382/168, 382/172, 382/181, 382/184, 382/194, 382/199, 382/203, 382/209, 382/218, 382/232, 382/254, 382/255, 382/274, 382/276, 382/286, 382/287, 382/305, 348/143, 348/165
• US Class Current: 382/100
• 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 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>

R_T;

R≧

G>

B;

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;

(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.

2. 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.

3. 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.

4. 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.

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

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;

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.

7. 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.

8. 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.

9. The method of claim 6 further comprising releasing an alarm.

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>

R_T;

R≧

G>

B;

S≧

((255−

R)*S_T/R_T);

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.

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

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

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

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

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

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