The human eye is a complex and very efficient tool, but it does have its limitations. One of the main problems is our inability to see very well without sufficient light. Our vision relies on light reflecting off items and being processed by the receptors that make up our eyes – there are millions of them – so once the light fades, we become severely hampered in terms of sight.
Many animals – especially those that live nocturnal lives – have eyes that are adapted to night vision. This includes a different array of receptors and larger pupils – the aperture that lets in the light. Think of how a camera works, and you get an idea of how this can help in terms of vision.
We can correct failing vison in our eyes by way of lenses. To be able to see better in the dark, however, we need special equipment. There are night vision devices that amplify the available light and give us better vision, and these are widely used by military personnel, pilots and others.
Thermal imaging is a different concept entirely, and is also used in a wide variety of military and commercial applications. What is thermal imaging, and what is it used for?
How Thermal Imaging Works
Whereas night vision devices amplify the light coming into the lens using sophisticated software and hardware, thermal imaging works on a different concept. Every living thing gives off heat in infra-red form – this is the wavelength at which it is emitted – and a thermal imaging camera or other device targets this heat signal.
The device initially focuses on an area in which it expects to see a person, animal or any other heat source. This is done using a very clever and special lens that detects infra-red light and heat. Within the device are a series of elements that scan the image coming into the lens looking for the infra-red signal.
This is done in a fraction of a second, and what happens is it builds up an image that is presented as a temperature picture, if you like. This is called a thermogram. Once this thermogram is converted within the device into electrical impulses, it is then delivered to the devices signal-processing system, a clever micro-computer that then arranges the impulses as a moving or still image.
A thermal image is viewed as a different array of colours, with the brightest being the warmest, so the user can now see where the most heat – and the likely life – is in the area.
Uses of Thermal Imaging
While the image presented by thermal imaging device may not be as clear and defined as that from a night vision scope, for example, it is nevertheless a very useful method of seeing what is happening in the dark. The uses for thermal imaging devices are many – check out the Thermal Imagers blog to review some of them.
The military use thermal imaging so that soldiers can find enemies in darkness; they are also used in cameras on helicopters and aircraft, to detect other craft and people. Likewise, the police use thermal imaging cameras on their helicopters – you may have seen this on one of the many TV programmes following the emergency services.
In a crash where vehicles are crushed beyond recognition, thermal imaging can be used to determine if there is anyone within. This is also useful for the fire and rescue service when searching damaged buildings.
In security thermal imaging cameras can be used to spot intruders, and can also be linked to an alarm system – turn to Powerpoint Engineering to find out more about the subject. We could list many more uses for thermal imaging cameras, but suffice to say that this clever technology is widespread, and becoming more so.