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US army is using lot these days.

2006-10-08 07:32:35 · 5 answers · asked by White Is The Color 1 in Science & Mathematics Physics

5 answers

First, I'll assume by night vision you are referring to the way the military and others use equipment to generate those funny green-TV looking pictures. With the proper night-vision equipment, you can see a person standing over 200 yards away on a moonless, cloudy night! Night vision can work in two very different ways, depending on the technology used.

Image enhancement -
This is a more commonly used method. In this method, small amounts of light in the surrounding area are converted into electrical energy. Electrons pass through a thin disk, and are multiplied, these electrons bounce off a phosphor screen which converts them back to light. This light is what the viewer sees and enables the viewer to see in the dark.

Thermal imaging -
This method uses the heat emitted by objects to its advantage and shows that to the viewer. The infrared light is detected by infrared-detectors and a detailed temperature pattern is created(Thermogram). The thermogram is converted into electric impulses, these impulses are sent to a signal processing unit, the processed signals are sent to a display and the image is shown.

2006-10-08 07:47:08 · answer #1 · answered by Show Me Sunshine 2 · 2 0

The rod cells in the eye are the more sensitive cells, so they are the ones used in unaided night vision. The cone cells come into play in brighter light to add resolution and distinguish color.

A telescope or similar tool can concentrate light over a large area and concentrate it.

Most of the tools already mentioned detect light outside the visible spectrum of the human eye and convert it by some means to something that is within our visible spectrum. Infrared is most commonly used. Deep infrared is particularly useful, since it can detect the large temperature difference between a living human and most surroundings.

2006-10-08 16:54:15 · answer #2 · answered by Frank N 7 · 0 0

Night vision can work in two very different ways, depending on the technology used.

* Image enhancement - This works by collecting the tiny amounts of light, including the lower portion of the infrared light spectrum, that are present but may be imperceptible to our eyes, and amplifying it to the point that we can easily observe the image.

* Thermal imaging - This technology operates by capturing the upper portion of the infrared light spectrum, which is emitted as heat by objects instead of simply reflected as light. Hotter objects, such as warm bodies, emit more of this light than cooler objects like trees or buildings.

2006-10-08 14:41:28 · answer #3 · answered by Amarbir Singh 2 · 1 0

also covalence security sys
infrared light
by filtering visible light
only infrared light is emmited
then we can clearly see subject

2006-10-08 14:36:35 · answer #4 · answered by tutorisland 2 · 0 2

hi there i play alot of war games like tom clany's splintercell he has night vision to see its a pair of sunglass but bigger

2006-10-08 14:41:13 · answer #5 · answered by Anonymous · 0 3

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