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| Flir Thermal Camera Question |
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| bostonman:
I have a Flir Thermal Camera - Model TG267 that I bought used. I'm new to thermal imaging and expected the image to show a more distinguishable separation of heat. As an example, my boiler has several routes of copper pipe along with a few gauges. The copper pipe and fittings are extremely hot and the face of the gauges are quite cool (especially compared to the hot copper pipes). When I aim the camera in this area, some of the copper pipe is blue, some is red, and the gauges show all red. Since all the copper pipe is hot (probably >120 degrees F), I expected to see red lines in all the directions of the pipes and some blue spots where the gauges are since the faces are much cooler than the copper pipe (and gauge fittings). Initially I suspected the cold concrete floor is throwing off the camera, so I aimed parallel to the floor and still got similar results. When I aim the camera at my concrete foundation walls and windows, I see blue for the window (it's currently around 45 degrees F outside), but the walls show a shade of red. I expected everything to be blue since the windows and walls should all be quite cool. I tried changing the image to rainbow and lava, but got similar results. Am I using the camera wrong? |
| bostonman:
I've been tinkering with this camera and still have some questions. Attached are four pictures. The two named 'Rainbow Color 1 and 2' were similar except I moved the camera a bit more to the right. It's a picture of my baseboard and window. As it shows, a bit more heat is shown rising on the wall in one picture versus the other. This is what I'm confused over, why do things change when I either change angles or change which objects are in the picture? The other two are the same picture, just two different modes. In the one named 'Iron Color' it shows more red (i.e. heat rising from the baseboard) than the one named 'Rainbow Color'. Am I just interpreting the images incorrectly? |
| Bud:
The camera is trying to auto range and give you the best contrast picture. It detects the coldest and hottest spots in a scene and stretches the palette to fit in the temperature span. As you change the scene even slightly, the span will be slightly different which is enough to re-fit the palette, changing the color of a same spot from the previous scene. In order to avoid this and get consistently mapped color you need to disable auto range (enable manual range). This will lock the mapping but may not give you best contrast picture, you will need to manually adjust lower and upper bounds of the temperature range. Not all cameras have manual range, typically mire expensive cameras do. As to different colors in two different palettes- you cant compare that, each palette has its own mapping of temperature to color. |
| bostonman:
This makes a bit more sense. Looking at my manual, I don't see a way to turn off auto range. Some images appear to be spot on with what I'd expect for a thermal image, but then other images baffle me. Sometimes an area is cold, yet, the camera shows some red. Although I haven't dug into this much, my assumption is that an area is red with respect to a cold area instead of it being red because it's extremely hot. I still don't understand why the pips and gauges on my boiler show blue on areas that should be red hot. My thought is the cold coming off the basement floor is interfering. Also, areas in my basement (non heated) such as my workbench show red areas indicated warmth, but most areas should be about 60 degrees F. The things that have fascinated me: if I press on an area with my hand, the heat that is transferred from my hand to the object remains warm for quite some time. I tried this on my where I placed the palm of my hand on the wall and my hand image remained for a good three-minutes. The way heat dissipates from my baseboards and stove is amazing. I think it's so cool to see the peaks and valleys of heat in an area. |
| Bud:
Regarding pipes and gauges, if they are bare metallic, this may throw thermal cameras off. Have a read on materials emissivity. For accurate measurements of a material you need to offset the camera with values specific to particular material. This works as a correction coefficient. Again cheap cameras do not have material emissivity setting. To test this you can place a strip of black electric tape over the pipe and look again. The part covered with tape will show correct temperature (less some loss through the tape). Or you can paint the bare pipe for an experiment. |
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