Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Thermal Imaging and Object Detection at Sea

  1. May 9, 2010 #1
    So my mind tends to wander, but I was thinking... since active/passive sonar is used to detect objects underwater, couldn't thermal imaging be used as well (in conjunction)? Isn't there any reason why we couldn't combine the two sensors into cooperatively working together to detect submarines, enemy swimmers, underwater mines, etc assuming the radiating heat is sufficient enough and to the required intensity of the thermal imager?

    Does this make sense at all? I was hoping to spur some discussion on the topic.
  2. jcsd
  3. May 9, 2010 #2


    User Avatar

    Staff: Mentor

    What is there under water that radiates heat? Most of the animals are cold blooded and those that aren't are heavily insulated due to the water's ability to remove heat quickly.
  4. May 10, 2010 #3


    User Avatar
    Science Advisor
    Gold Member

    I don't know for sure, but my guess why it hasn't been done is because water is opaque to infrared, meaning you can't "image" underwater in the infrared spectrum.


    My suspicions are correct. The following picture shows that water absorbs infrared much more readily than visible. This means if you can't see it with visible light, you certinly won't see it in infrared.

    [PLAIN]http://www1.lsbu.ac.uk/water/images/watopt.gif [Broken]
    Last edited by a moderator: May 4, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook