
Originally Posted by
dullbird
That's strange Chris because I have found kittens in walls using a tic.
and if you go and look at the demo on flir site they claim you can see insects in the roof and behind walls.
I would imagine there has to be a big difference in temp in order to be able to spot stuff. A 36/37 degree kitten is probably easier to spot in a cool wall cavity then a person walking behind a plastic sheet where the body temp might only be a 10/15 degree difference with the ambient temperature.
That's the only explanation I can come up with all I know is despite what you say we call fire rescue out a lot and use them when we are struggling to locate. They don't work in every situation but we have used them and they have worked
Thermal imaging camaras work by picking up infrared radiation that is emitted or reflected by all objects. Thermal radiation can easily pass through most gases but passing through solids and liquids is either difficult or blocked. So the radiation can either be emitted, absorbed or reflected. Put a thermal camera in certain situations and you can get false temperature readings due to reflected heat (stand in front of a dull aluminum sheet and point the camera at it - you'll get a reflection of your own emitted body heat). Point a thermo camera at a liquid and you'll only see the surface temp, not the actual temp of the liquid (narrow the span down enough and you can see the convention currents in a cup of coffee)
End of the day the kitten or insects behind the wall would actually have to be close enough to it to affect the temp of the wall before you could pick up the increased temp. Good quality thermal cameras (most likely any dedicated thermal camera nowadays) would be able to pick up temp differences of less than 1 Deg, the trick is setting it up right So it helps when you know what your looking for
Shane
2005 D3 TDV6 loaded to the brim with 4 kids!
http://www.aulro.com/afvb/members-rides/220914-too-many-defender-write-ups-here-time-d3.html
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