Speaker 1: I am Scott and I'm Then and we're from car Stuff.
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Speaker 1: get your podcast. Welcome to brain Stuff from how Stuff Works. Hey,
Speaker 1: brain Stuff, this is Christian Seger. So night vision seems
Speaker 1: like a pretty cool idea, right, I mean, you see
Speaker 1: it all the time in movies. Some secret agent type
Speaker 1: straps on a pair of goggles, sneaks into a luxurious
Speaker 1: supervillain compound and mows down enemies under the cover of darkness,
Speaker 1: or the Predator stocks Arnold Schwarzenegger killing his platoon one
Speaker 1: by one by one. And as you're watching all this,
Speaker 1: you may occasionally ask yourself, Hey, do those goofy looking
Speaker 1: goggles really work? Well? The answer is yes, absolutely. With
Speaker 1: a good night vision device or n v D, you
Speaker 1: can see a person standing over two hundred yards or
Speaker 1: a hundred and eighty three meters away on a moonless,
Speaker 1: cloudy night. And whether we're talking goggles, scopes or cameras,
Speaker 1: Most of these devices rely on one or two types
Speaker 1: of night vision, image enhancement that's the green looking one,
Speaker 1: and thermal imaging, which is the bluish gray stuff. They
Speaker 1: both produce results, but work in different ways. Thermal imaging
Speaker 1: captures the upper portion of the infrared light spectrum. Objects
Speaker 1: emit this as heat rather than reflecting it as light.
Speaker 1: Hotter objects, such as the bodies of secret agents, emit
Speaker 1: more of this light than cooler objects like buildings, trees,
Speaker 1: or you know, dead bodies, and that's what you're seeing
Speaker 1: when you use thermal imaging, essentially a measure of temperature
Speaker 1: from negative four degrees fahrenheit to three thousand and six
Speaker 1: hundred degrees fahrenheit. The magic, or well, you know, the
Speaker 1: science starts at the lens, which focuses the infrared lightmitted
Speaker 1: by all of the objects in view and uses a
Speaker 1: phased array of infrared detector elements to create a temperature
Speaker 1: pattern called a thermogram, which is translated first into electric
Speaker 1: impulses and then into data for the display, where it
Speaker 1: appears as various colors depending on the intensity of the infrared.
Speaker 1: Then there's image enhancement. This collects tiny amounts of light,
Speaker 1: including the lower portion of the infrared light spectrum and
Speaker 1: amplifies it. Devices using this approach rely on an image
Speaker 1: intensifier tube to collect and amplify light, both the infrared
Speaker 1: kind and the visible stuff. Image enhancers use a photo
Speaker 1: cathode to convert photons into electrons and high voltage to
Speaker 1: amplify those electrons in a micro channel plate or an
Speaker 1: m c P before they hit a screen that's coated
Speaker 1: with phosphors. Here's the crazy part. These electrons maintain their
Speaker 1: position in relation to the micro channel they passed through,
Speaker 1: which provides a perfect image. Since the electrons stay in
Speaker 1: the same alignment as the original photons. When they hit
Speaker 1: the screen, their energy excites the phosphors, releasing photons. Those
Speaker 1: phosphors create the green image you see when you look
Speaker 1: through a night vision scope. Check out the brain Stuffed
Speaker 1: channel on YouTube, and for more on this and thousands
Speaker 1: of other topics, visit how staff works dot com.