I am trying to import Thermal data from a FLIR Zenmuse xt radiometric lens thermal camera.

Flir does not include a conversion with the camera and does not respond to my emails regarding the conversion.

On the Pix4D website they include the conversion for the camera which is

"0.04 * [Thermal Image] - 273.15"

This equation works for the most part but some images can be as much as 30 degrees F off.

Currently working in QGIS to apply the Pix4D conversion using raster calculator.

I have attached the TIFF as well as the .RJPEG for viewing in Flir tools.

Please let me know if you have any questions or if there is anything else I need to add.

The general temperature range I am looking for is 32.8-106.6 F

Thermal images can be found here https://drive.google.com/drive/folders/0BzQ1355jgmF9Y0kycmdlcWZiLVE?usp=sharing

  • I have the same problem with Erdas imagine. Could you please write and share the last formula you used in QGIS calculations? – Mehmet May 28 '17 at 11:10

I've just tryed the images you post with the adjusted index from Pix4D on the raster calculator of QGIS. It gives me good results, then I've tryed out the JPEG Image on Flir Tools and you can match the results from the JPEG to those on the TIFF by adjusting the emissivity values and T reflect.

  • Adjusting the emissivity and reflectance values I was able to align the images a little better however, some areas still appear to be 10-20 degrees (Fahrenheit) off. Overall though the differences between hot and cold areas appear to be the same in both images meaning that both the .Tiff and .JPEG have the same temperature difference from hot to cold. What is most important to these images is that reflectance is linear with the digital number, which they appear to be. Thanks! – Reisenrich May 1 '17 at 13:09
  • Yep, thats the most important thing, that the TIFF has a linear behavior in reference with the RJPEG. Thanks you for the information on the index, that allows us to use QGIS to manage Thermal TIFF and save on superexpensive software as ResearchIR. – Daniel Gamboa May 2 '17 at 14:04

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