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Surveillance systems: Night vision devices are important components

Most surveillance systems are not complete without a night vision device. Available in many models and styles from goggles to binoculars, night vision devices (NVDs) are integral parts of many surveillance systems. Here's some general information on how they work.

Equipped with NVDs, surveillance systems can detect a person over a distance of 200 yards on a cloudy, moonless night. NVDs work in one of two ways: Either by image enhancement or thermal imaging.

Image enhancement NVDs use a combination of optics and electronics to collect tiny amounts of light for surveillance systems. This light includes the infrared range of the spectrum, which is normally invisible to the human eye. Light enters the device and strikes a device known as a light intensifier tube where the light is transformed into electrons. The electrons strike a phosphor-covered screen, causing the phosphors to glow, just like a conventional TV screen. The small, green-hued image on the internal monochrome screen is then viewed through an eyepiece by the observer.

Thermal imaging technology creates images by capturing infrared light that is emitted as heat by objects. Warm bodies are usually hotter than the surrounding objects like buildings and trees and are very easy to see and track with this type of NVD. In thermal imaging, a special lens focuses the infrared light emitted by all the objects in a certain area of view. An array of infrared detector elements scans the light and creates a thermogram. The thermogram is converted into electrical impulses which are in turn sent to a signal-processing unit that interprets the impulses, creates the image and sends it to the display. Various colors appear on the display according to how much heat is emitted by the objects in the view. Thermal imaging technology is a very useful tool in some surveillance systems.

To learn more about night vision devices and surveillance systems, click one of the links below to read complete descriptions and specifications of NVDs.

Binoculars
Telescopes
Rifle Scopes
Night Vision
Spotting Scopes
Laser Sights
Range Finders
Night Vision Goggles

About The Author:

Rita Liotta is a successful author and publisher at www.1st-at-binoculars.com.  Recommending binoculars, telescopes, rifle scopes, night vision, spotting scopes, laser sights, range finders & night vision goggles.
10-06-04