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| Quadro : Night Vision Binoculars |
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| Night Vision Goggles |
The working principle of night vision depends upon what type
of technology is being used. There are several types of technology that can be
used like Low-Light imaging, Near-Infrared Illumination, Thermal Imaging
etc.
Before we discuss about the technologies, it’s important to know
that all light is not visible to us. Our eyes sense only some particular part
of electromagnetic spectrum (light). The light we can see — called visible
light — is only a part of the overall electromagnetic spectrum (all types of
light). There are other types of light, such as infrared and ultraviolet light,
that can’t be seen by the naked eye.
If you want to see in the dark then the
first way requires a type of technology called image enhancement.
This basically
means that equipment takes what is there and enhances it to make the most of
it. Night vision goggles use image enhancement technology to collect all the
available light (including infrared light) and amplify it to make it visible to
our eyes because even in the darkest of condition , there are some light
present (like infrared).
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| Image Enhancement |
The other technology is called thermal imaging. When you
hear about the word “thermal,” then you know that this technology has to do
with heat. Hot objects like human or other animal bodies, emit some heat in the
form of infrared light. Night vision goggles use thermal imaging technology to capture
the infrared light being emitted as heat by objects in the field of view. In
this way, you can see an image of what’s going on in the dark based upon the
amount of heat being generated by various objects. Thermal imaging works well
when trying to detect people in the dark. It’s better to use thermal imaging
for conditions approaching absolute darkness. However, most night vision
equipment uses image enhancement technology (less expensive). Night vision
goggles are intensively used by the military and law enforcement agencies. Some
wild life researcher also uses to watch animals at night.
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| Thermal Imaging |
You may notice that night
vision image always has a green glow. That’s for our better visual experience.
Because when light is captured and amplified, it’s turned into electronic
information which is colorless and later that has to be transmitted to the eyes.
Night vision goggles are made with screens that produce green pictures, because
human eyes are more sensitive to green light and it’s easier to look at green
pictures for long periods of time than it is to look at black and white
pictures. Though thermal goggles give black and white images, some goggles use
false color which is an excellent way of better distinguishing between objects
at different temperatures.
