Project no. Fp6-018505 Project Acronym fire paradox

2.3New Technologies

The use of new technologies has been one of the demands of foresters and technicians working with forest fires (Colaço et al, 2007). Much research has been done in the past years about this subject. Not only concerning the use of several kind of cameras (video, infrared), but also with the use of laser detection, satellites for remote sensing, and unmanned aerial vehicles (UAV’s).

2.3.1Surveillance Cameras

Both terrestrial means as well as aerial means can utilize cameras to perform fire surveillance. The terrestrial systems, usually have one or more remote stations, placed in the terrain, that are in permanent communication through radio links, GSM, GPRS, or other communication lines with the coordination centres.

Most of the new technologies consist on information gathering and delivery of fire data and images to operators working on the Coordination centres or in the local command post. The detection and precise location of the fire spot depends on trained operators through their previous knowledge of the cameras positioning or with the help of geographical information systems (GIS). If the system is manual, all the steps to detect, verify and give the alarm are done by the operator. However, if the system is semi-automatic, although the detection and fire alarm continue to be automatic, the operator performs the fire confirmation and verification.

The most common types of cameras are:

1. 
   Cameras in the visible domain – cameras that transmit images on the visible domain to a central communication centre. The detection is made through image transmission to a screen, visualized by an observer or by automatic comparison of images (FAO, 2001).
   

Figure 5 – Lookout tower with a camera TV in Poland

i) Advantages of the visible ground cameras:

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  Surveillance is centralized in just one centre;
  
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  It’s possible for just one observer to control several surveillance cameras, which can diminish the number of human resources required to control a forest area;
  
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  Working in a room, the observer has better living and safety conditions to perform his duty.
  

ii) Disadvantages:

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  Less precision on detection;
  
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  Higher technical complexity;
  
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  High installation and maintenance cost.
  

2. 
   Infrared (IR) cameras – a camera operating in the infrared domain (wavelength range 10 – 12,5 µm). The IR cameras capture the radiation released by warm bodies. The detection is automatic by comparison of images, and the alert is given to the control centre. (FAO, 2001.
   

Figure 6 – Thermal (IR) camera in France

i) Advantages of the IR ground cameras:

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  Precision of location as information captured is associated to a GIS;
  
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  Provides a picture in real time and continuous weather observations, temperature, relative humidity and wind;
  
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  Possibility of operating in mist or low visibility;
  
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  Automation of detection;
  
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  Effective in night detection.
  

ii) Disadvantages:

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  High cost of instruments, installation and maintenance;
  
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  Limited scope exclusive to exposed areas;
  
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  Complexity of instruments for use;
  
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  Does not detect smoke (possible earliest stage of fire).
  
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  Very susceptible to theft or vandalism.
  

These cameras can have a permanent position or rotate to a full 360 degrees to capture successive IR or video images of the territory. To complement the information given to the operators, the systems can work simultaneously or separately. The use of these systems is not exclusive of terrestrial means; it can also be used by aerial means of surveillance.

Some other countries use laser detection systems. These systems are based on the following principle: a laser ray is sent in a specific direction, if it intercepts a smoke mass, a portion of the emitted photons is reflected by the smoke arriving to the sender. The time taken by the photons to travel (sender – smoke – sender) is used to calculate the distance from the emissary to the fire spot.

2.3.2UAV’s and Satellite detection

In this field, we include unmanned aerial vehicles (UAV’s) and satellite based detection.

The unmanned aerial vehicles (UAV’s) can be airplanes, helicopters or balloons, that fly without a pilot and are controlled by the command centre. Usually these UAV’s have cameras installed that transmit pictures, video images or infrared images.

The system has the following advantages:

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  Low acquisition and operational cost compared to other air platforms
  
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  24-hour operational capacity
  
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  Does not put the pilot’s life at risk in such extreme conditions
  
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  Extensive areas guarded
  
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  Extremely accurate geo-referenced monitoring
  
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  Broadcast information
  

The systems based on satellite detection have been a target of research and development over recent years. Usually a group of sensors implanted on low altitude orbit satellites constitutes them. The sensors perform the detection and wildfire monitoring, through land surface scanning while completing its orbital trajectory.

It’s a very common system used to execute surveillance on large forest areas, where it is difficult to accede and the Human presence is very weak or non-existent. Usually this system provides detection data 3 times a day, however, for a prompt response in case of fire detection, the use of satellites is not very efficient.

Some countries with large areas without a strong presence of people such as Russia, Brazil, China, among others, use this system to detect fires in very remote areas.