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Originally Posted by thstone
"(night vision is basically a camera that detects IR light). "
Let's be careful in using terms so we don't confuse anyone - there are actually three types of technology used for night vision:
The technology that most people call "night vision" works by amplifying the very low level of visible ambient light that our eyes cannot detect. A better name for this technolgy is "light amplification". This technology creates the classic "green" scene images that we've all seen from the military. The military likes this approach because it is passive in nature and will not give away a soldiers position.
Alterntively, other night vision devices use an energy source (just out of the visible range in either near-wave IR or UV) to illuminate a scene in a wavelenth that humans cannot see. This is an active technology and is kind of like mounting your old hippie black light from your garage to a camera that detects the black light. Obviously the military doen't like this approach because this type of device can be easily dectected by an IR or UV sensor which would immediately give away your position but it is useful for other situations and can provide very good quality images because there is an actual source of energy illuminating the scene. These images are characteristically black and white (not green) with a bright spot (more white) where the illuminator energy is strongest.
Otherwise, true IR cameras detect heat or thermal energy and can be used for night vision but only objects with different temperatures can be resolved. This can be helpful when searching for a Sasquatch (hot) in a forest where the ave temp of the background forest is colder than the Big Foot or any other hot blooded animal but many objects can go undetected or unresolved because they are same or close to the same in temperature as the surrounding background (e.g. cold blooded animals or made made objects). These images are recognizable by their wide range of full colors (red, yellow, green, and blue) with bright red being the warmest and dark blue being the coldest.
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Thanks for the information, I'm not very educated in military technology myself and it was unwise to use it as an example. However, I think you understand what I was trying to say.