Night vision goggles make use of the imaging device which has the ability to detect visible and infrared light sources and amplify them to provide visible images which can be viewed even in complete darkness. Night vision goggles are commonly used by the military, but can also be used by the general public as well. These can be found in a number of shops and stores and can either be held in hands or mounted to the helmet.
Before these were available to the general public, only the military and law enforcement agencies could use it. The military used it during the Vietnam War and since then it has undergone numerous stages of development. These days, there are highly superior kinds available which are really effective and can even detect a person standing more than 200 feet away in complete darkness.
They are available in many different sizes and generations. Generations are used to refer to the superiority and at present the US Military uses 4th generation version which is the most superior of all. The prices of the night vision goggles also vary considerably depending on its quality. You can buy one for just a few hundred dollars or one which costs more than five thousand dollars.
The two kinds which are available today include the passive ones and the active ones. Passive goggles use light which are available within the immediate area, while the active goggles project infrared lights. There are also some which makes use of both these techniques.