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Well, if the person is wrapped tightly I expect the answer is "no", but could an aluminized loose "cloak" hide a person from thermal imaging cameras by reflecting the cold surroundings? Or, if the blanket is used as a hide (impromptu tent) with a person inside, would that work?

  • See also http://physics.stackexchange.com/a/147483/26969, http://physics.stackexchange.com/a/135843/26969 – Floris Feb 27 '15 at 13:47
  • The "original answer" does not answer my question. I do not consider this a duplicate. –  Feb 27 '15 at 20:36
  • The original answer and the links therein show that you get progressively lower radiation as you add more layers - one layer is definitely not sufficient. Especially if you take into account the second answer - if you truly isolate the person (no heat loss at all) they will eventually overheat and die. So I believe that the answers given in the duplicate get us to "no", just as you surmised. – Floris Feb 27 '15 at 20:42
  • And of someone in a tent or with significant air spacing, which was the core of my question? How about air flow? Or the absorption of body heat into the ground for someone lying down in such a situation? Any videos or is the answer given just speculation? –  Feb 27 '15 at 22:05
  • If the tent is sufficiently large, the rate at which it is being cooled by convection will exceed the rate by which it is heated by the body's radiation, and its radiation signature will be hard to distinguish from background. But then a sufficiently large tent may itself become quite a visible thing... – Floris Feb 27 '15 at 23:40
  • So what is "sufficiently large" in the context of thermal imagers? –  Feb 28 '15 at 20:10
  • Well, a gram of experiment is worth a tonne of theory. This video would suggest that the "original" answer to this so called duplicate question is seriously flawed from a practical POV: https://www.youtube.com/watch?v=9PLo5iCEcX4 –  Feb 28 '15 at 20:40
  • The video shows a multi layer approach - just as the original (dup) answer suggested. And as I said - if you can keep the heat transmission low compared to the rate of cooling by the environment, you're good. Which means insulation that goes beyond the simple mylar safety blanket. Perhaps I misunderstood what you meant by "aluminized blanket" - I thought you were talking about something like this. Adding insulation changes everything. But you have encouraged me to update the original answer - I hope you think it less "flawed" now. – Floris Feb 28 '15 at 22:38

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Aluminum reflects infrared, so it is something like wrapping yourself in a mirror. The camera wouldn't see you, but it would see something.

One the other hand, you are an infrared light bulb. So not seeing you is very helpful.

mmesser314
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