Why is everything green in night vision goggles?
Asked by
ETpro (
34605
)
March 22nd, 2010
I can understand why we don’t see full, vibrant color as we do in sunlight. The night-vision device is recording only the infrared wavelength, so full color is not possible, as there is no spectrum of wavelengths to support it. But why not grayscale? It seems to me a black and white TV images is easier to visually decode than the strange green world of night-vision technology. Why green>
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10 Answers
They were purposefully designed to show green because the human eye can distinguish more distinct shades of green than any other color, making it easier to see details.
I believe it has to do with our eyes being most sensitive to the green wavelength.
EDIT:
@Mariah Yeah, what you said :).
To be environmentally conscientious of course.
** Night Vision is deliberately green in color as shading levels in green are the easiest for the human eye to distinguish. Night Vision used to also be available in red, but scientists later determined that green was easier to see and use.
Besides being easier to see, green is also a single wavelength and easier to produce. Shades of gray require white light which is made up of red, blue, and green. That is more difficult, expensive and distracting.
@Mariah I think that’s enough GA. I’d give you another one but you have too many. Also Black Hawk Down wouldn’t be the same without the green.
@Mariah Awesome answer. Unfortunately, they don’t have a button to click for that, so I’ll try to remember to click GA on some other thread as well for you.
@jaytkay Thanks so much for that link. It’s a great cartoon and though I always loved Calvin & Hobbes, one I hadn’t seen.
@Pretty_Lilly & @worriedguy Kudos and a GA for the added details. Thanks.
Night vision glasses “see” infrared wavelengths, ie heat from nearby heat sources. These images emit very weak signals, the glasses use an electron cascade tube or receiver (can be known also as a photo multiplier tube). This tube takes the weak infrared light or photons and amplifies them in a series of cascades as the photons make their way down the tube, at each cascade the photons are multiplied until they have enough energy to be seen as green light. There are devices (much more expensive) that can add false color to the image depending on the energy of the incoming photon from the heat source. The green light glasses are the standard type that are commonly available.
@MaryW Thanks for a very clear explanation.
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