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Thermal versus optic cameras

Until now, a conventional CCTV system has been one of the most effective surveillance and security measures. It has proven its worth time and time again. Where the extra electronic ‘eye’ is in place, people tend to think twice before attempting to commit a criminal offence.

Urban surveillance systems in cities like Johannesburg have a proven track record. Evidence of theft, hijackings and accidents, to name but a few, has been captured by the cameras - in some cases without the offender even being aware that his or her actions were being monitored.

But, CCTV cameras are not the perfect solution. In order to see with a visual optic camera, light is required. During the day it is seldom a problem, but darkness, smoke, fog or dust are some of the factors that can create problems.

Thermal imaging cameras are an option in cases where visual cameras may fail to perform optimally. Humans need light, white light specifically, to be able to see. White light passed through a prism breaks up in to various colours that we can see with our eyes. The spectral range is between 3 and 6 microns (a very small portion) in the electromagnetic spectrum.

Infrared is between 6 and 13 microns - twice the range. In order to see that spectrum, specialised equipment is needed. The thermal camera is just that. It takes the thermal energy emitted from a body and converts it into an image that is visible. The thermal image is portrayed as a thermograph (a picture of heat). Through analysis techniques, that thermal image can tell a story never before told.

Thermal imagers are available for the first time outside the military and the industrial market. With a thermal camera, no illumination is required. Shadows, which intruders often use to hide or move in, are thus eliminated.

The thermal camera detects temperature differences and a crisp, high-definition image of the person or object is delivered. With sensitivity levels of 0,08°C, subtle differences in temperature will form the defined image of the object.

With the technology provided by thermal imagers, the ability to see in pitch darkness and penetrate fog is now a reality. With the correct optics on a thermal camera human size figures can be detected from as far as 30 kilometres away.

Coastal estates, such as golf estates, have implemented thermal cameras as a solution to their concerns of creating a secure environment for the investors and residents.

There is a range of thermal cameras available for various applications, but they all share the same quality and benefits - they all see heat.

Thermal cameras will never replace conventional CCTV cameras for everyday applications, but are becoming increasingly popular in applications such as border security; high value site protection; industrial security; perimeter security; force protection; coastal surveillance; deployable security; asset surveillance; port security; airport security; and urban surveillance.

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