Why do night-vision cameras use infrared detectors?
Shizuka H asked:
Just a question-
Why do night-vision cameras use infrared detectors?
Just a question-
Why do night-vision cameras use infrared detectors?
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November 9th, 2009 at 1:18 am |
Probably because people are giving off infrared but no visible light at night.
November 9th, 2009 at 12:38 pm |
so you can see bodyheat instead of using a light
November 11th, 2009 at 5:36 am |
Infrared detectors work by detecting the difference in temperature between objects and air. Almost always, it gets cooler at night. Objects absorb heat during the day and release the heat at night, which makes them visible to an infrared detector. A brick wall will normally be much warmer than the night air, so will it show up as a bright white. Tree leaves are too thin to hold much heat, so they appear black. People and animals generate their own heat and tend to be very bright. Running engines and mufflers are even hotter.
If the air temperature happens to be the same as skin temperature, around 87 degrees, the human body does not show up very well in infrared scopes. You can still see them breathe though. The lips and breath are closer to the internal body temperature of 98.6.