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.

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