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The Way Night Vision Works
by: Shawn Davis
Most people are familiar with the concept of night vision.
After all, it is seen in countless action and spy movies.
However, the truth is that night vision is more than a fantastical
concept; it is reality. And with goggles, night scopes, binoculars
and monoculars, it is possible to see on a moonless, cloudless
night. In fact, the technology is so advanced that you can
see a person standing more than 200 yards away. That’s twice
the length of a football field! The remarkable feat of human
sight at night is accomplished one of two ways: image enhancement
or thermal imaging.
Image enhancement is a night vision technique that collects
tiny amounts of light that may not be perceptible to the human
eye. These are the smallest glimmers of light, sometimes even
on the lower end of the infrared spectrum, that are discovered
by the device in use. The points of light are than amplified
by the device to a point that allows the object or person
to be seen easily.
The other way night vision works is by thermal imaging. This
is technology that works exclusively in the upper portion
of infrared light. Rather than gathering reflected light,
this is heat that is given off by objects or people. This
is known as thermal infrared, and it occupies the largest
amount of space as part of the infrared spectrum (which is
at the lower end of the light spectrum, below what is detectible
by the human eye). This means that there is a great deal of
wavelengths that can be detected by the proper devices. Because
thermal imaging works by putting the heat coming from objects
in visible form, it is to be expected that some objects will
appear clearer than others. Humans, for example, emit more
heat than a tree, and so a tree will not be as clear.
Night vision products make excellent additions to any surveillance
collection, and they can be very helpful in locating objects
or people in dark places. You will pay in a price range from
under $300 to more than $15,000, depending on features, accuracy,
and purpose of the accessories you choose to aid your night
vision.
(c) 2005 Copyright www.spyassociates.com.
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