System and method for fire detection

Abstract

A system and method for detecting radiation indicative of fire, such as forest fire. In one embodiment, a threshold energy level is determined based on ambient sensor conditions. A sensor unit may be setup to scan a predetermined area for electromagnetic radiation. Any detected electromagnetic radiation may then be band pass filtered to a wavelength range centered about a predetermined frequency associated with the presence of fire. The resulting energy level signal may then be further filter to pass only those signals which exhibit a “flicker” frequency. If the resulting filtered signal exceeds the threshold signal, a fire notification signal may then be generated.

1 - 29 . (canceled)  
   
   
       30 . A method for fire detection comprising: 
 taking a plurality of energy samples during a normal scan mode;    computing a plurality of energy values for each of said plurality of energy samples;    comparing each of said plurality of energy values to a dynamically computed threshold value based on ambient infrared energy levels;    entering a detect mode when one of said plurality of energy values exceeds the threshold value more than a predetermined number of times during said normal scan mode.    generating a fire notification signal if the one of said plurality of energy values is greater than said threshold value over an extended period of time.    
   
   
       31 . The method of  claim 30 , further comprising filtering said plurality of energy samples to a wavelength range centered about 4.3 microns in the infrared spectrum.  
   
   
       32 . The method of  claim 30 , further comprising filtering said plurality of energy samples to a flicker frequency range between 1 and 10 Hertz.  
   
   
       33 . The method of  claim 30 , further comprising 
 rotating a mirror of an infrared sensor in a circular path;    pausing said mirror on each of a plurality of bearings along said circular path, wherein each of said plurality of bearings spans a predetermined number of degrees; and    taking the plurality of energy samples for each of said plurality of bearings using said infrared sensor during said pausing.    
   
   
       34 . The method of  claim 30 , further comprising: 
 taking additional energy samples during the detect mode at a bearing corresponding to said one of said plurality of energy samples;    normalizing said additional energy samples;    comparing said normalized additional energy samples to the threshold value; and    generating said fire notification signal when said normalized additional energy samples exceeds said threshold value.    
   
   
       35 . The method of  claim 30 , wherein said threshold value is dynamically adjusted based on said plurality of energy samples.  
   
   
       36 . A system comprising: 
 a sensor for receiving a plurality of energy samples during a normal scan mode; and    a processor coupled to the sensor, the processor configured to:    compute a plurality of energy values for each of said plurality of energy samples,    compare each of said plurality of energy values to a dynamically computed threshold value based on ambient infrared energy levels,    enter a detect mode when one of said plurality of energy values exceeds the threshold value more than a predetermined number of times during said normal scan mode, and    generate a fire notification signal if the one of said plurality of energy values is greater than said threshold value over an extended period of time.    
   
   
       37 . The system of  claim 36 , further comprising a first filter coupled to the sensor for filtering said plurality of energy samples to a wavelength range centered about 4.3 microns in the infrared spectrum.  
   
   
       38 . The system of  claim 37 , further comprising a second filter coupled to the sensor for filtering said plurality of energy samples to a flicker frequency range between 1 and 10 Hertz.  
   
   
       39 . The system of  claim 36 , further a mirror controllable by the processor and configured to direct said plurality of energy samples to the sensor, said processor being further configured to: 
 rotate the mirror of an infrared sensor in a circular path,    pause the mirror on each of a plurality of bearings along said circular path, wherein each of said plurality of bearings spans a predetermined number of degrees, and    take the plurality of energy samples for each of said plurality of bearings using said infrared sensor during said pausing.    
   
   
       40 . The system of  claim 36 , wherein the processor is further configured to: 
 take additional energy samples during the detect mode at a bearing corresponding to said one of said plurality of energy samples,    normalize said additional energy samples,    compare said normalized additional energy samples to the said threshold value, and    generate said fire notification signal when said normalized additional energy samples exceeds said threshold value.    
   
   
       41 . The system of  claim 37 , wherein said threshold value is dynamically adjusted based on said plurality of energy samples.  
   
   
       42 . A method for fire detection comprising: 
 taking a plurality of energy samples at each of a plurality of bearings along a circular path, wherein each of the plurality of energy samples are taken over a first period of time;    computing a plurality of energy values for each of said plurality of energy samples;    comparing each of said plurality of energy values to a threshold value;    determining if the threshold value has been exceeded at one or more of the plurality of bearings;    taking additional energy samples if the threshold value has been exceeded at one or more of the plurality of bearings, wherein each of the additional samples are taken over a second period of time, where the second period of time is greater than the first period of time; and    generating a fire notification signal responsive to said additional energy samples.    
   
   
       43 . The method of  claim 42 , further comprising filtering said plurality of energy samples to a wavelength range centered about 4.3 microns in the infrared spectrum.  
   
   
       44 . The method of  claim 42 , further comprising filtering said plurality of energy samples to a flicker frequency range between 1 and 10 Hertz.  
   
   
       45 . The method of  claim 42 , further comprising: 
 normalizing said additional energy samples to said first period of time; and    comparing said normalized additional energy samples to the threshold value.    
   
   
       46 . The method of  claim 45 , wherein said generating comprises generating the fire notification signal when said normalized additional energy samples exceed the threshold value.  
   
   
       47 . The method of  claim 42 , wherein taking the plurality of energy samples comprises taking the plurality of energy samples during a normal scan mode, and wherein taking the additional energy samples comprises taking the additional energy samples during a detect mode.  
   
   
       48 . The method of  claim 42 , further comprising entering the detect mode in response to determining that the threshold value has been exceeded at one or more of the plurality of bearings.  
   
   
       49 . The method of  claim 42 , wherein said threshold value is dynamically adjusted based on said plurality of energy samples.