home ::surveillance

Surveillance: Understanding the generations of night vision devices

For surveillance, night vision devices are essential. There are two basic types of night vision devices (NVDs), image enhancement and thermal imaging. This article describes the terminology that is used to refer to the various levels or "generations" of technology used by image enhancement NVDs.

Generation 0 NVDs for surveillance use something known as active infrared. This means that the NVD projects a beam of near-infrared light onto the subject. This light, which is invisible to the naked eye, reflects off the subject and back to the device, where it is converted to an image by an image intensifier that projects the image (actually in the form of electrons) onto a small internal screen. The screen is viewed through an eyepiece by the observer.

Generation 1 NVDs use passive infrared. These devices use the ambient light from the moon and stars to create an image. The drawback with these instruments is that they do not work well on a cloudy, moonless night. Generation 1 NVDs use the same technology that Generation 0 NVDs use to produce an image for surveillance.

Generation 2 NVDs contain improved technology for passive infrared surveillance. The improvements enabled better images in low light conditions by virtue of increasing the number of electrons that create the image. This was accomplished by addition of a microchannel plate to the image intensifier, resulting in better and brighter images.

Generation 3 NVDs are what's currently in use by the US military. Although they use basically the same technology as other generations, benefits derive from the use of gallium arsenide in the process that produces the electrons that create the image. Images for surveillance again are brighter and clearer.

Generation 4 NVDs can respond to fluctuations in the ambient lighting conditions in an instant. The user can move from a high-light area to a low-light area without losing clarity or quality in the images viewed. This is important to moving surveillance operatives who wear night vision goggles.

Generation 0 and 1 are the most widely available NVDs at price points most of us can afford. To learn more about NVDs and surveillance, click one of the links below to see specifications and complete descriptions.

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