Archive for March, 2007

Seeing in the dark

March 7th, 2007 by Gene

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We’re going to peek into the dark places – night vision. Today on Engineering Works!

If you like action movies, you’ve probably seen night vision devices — goggles or telescope-like things that show you the bad guys in shades of green. They’re more than a Hollywood invention. Night vision devices – NVDs – really work. Troops in Afghanistan and Iraq use them every night.

NVDs use some high-powered engineering to turn dark into light. Let’s see how.
One way is called image enhancement. Image enhancement works like a radio receiver for light waves. This receiver receives little bits of light, so slight that our eyes can’t see them, and amplifies them the way a radio amplifies a weak signal — to the point that we can see what’s there.

The other is thermal imaging. Thermal imaging collects infrared light, light our eyes can’t see. We feel infrared light as heat instead of seeing it. Thermal imaging converts infrared light into images we can see.

The first night vision gear was used during World War II. It used a sort of infrared floodlight and special receiver to light up targets with infrared light. The equipment was bulky and heavy. And the images were hard to make sense of. Since then, engineers have made it lighter and easier to use, with sharper images.

We usually think of soldiers using NVDs. But police and rescue specialists use them, too.

We’ll see you later. Even if you’re in the dark.