Heat Paint

October 2nd, 2013

Rendering visible the more abstract properties of a scene still intrigues me, and while my earlier tinkering with mapping temperature to colour was a bit limited, I was inspired to take it a little further. So, exhibit one: a familiar junction, lit in a conventional way to look purdy:

This time around, I’m still working with temperature, and representing it with colour. However, where before I was measuring air temperature, this time I’m measuring it at the surface. As before, a high and low temperature bound are set based on sampling the environment before the shooting begins, and in this case the low was around 20.2 degrees celsius, and the high around 23. On a practical level, the benefit of the surface sampling for my purposes here is that I get a super-accurate reading every second, rather than the gradual shift over minutes that the ambient sensor yields.

Colour mapping was set to run from green for cool, to red for hot, and I’ve improved the interpolation of intermediate colours for temperatures that fall somewhere in the middle of the range. Most significant, though, is that instead of just displaying some kind of floating indication, this new setup projects the coloured light onto the sampled area, which a nerd friend suggested a while back. So, the end result is a more intuitive visualisation of the heat distribution in the scene.

I almost want to call it a false-colour representation, but at least from a photographic perspective these were the actual colours involved…

Note the warm water spilling from the right-hand tunnel, and the cool water flowing from the left!

As always, field testing brings up obvious limitations. In this case, the fact that the actual processing hardware has indicator LEDs on it was blindingly obvious, and was the biggest pain; a shirt wrapped around it mostly resolved things. Second most frustrating was the fact that I’d configured the light to pulse on briefly on a button press. What I really needed was it to be constantly illuminating, updating temperature reading and colour each second, so that I could focus on moving it around. If I’d taken a laptop I could have fixed that, but for some reason I opted not to :P Next time!

One Response to “Heat Paint”

  1. Kittyon 08 Jan 2015 at 10:01 am


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