Anafi Thermal Images Using Lepton 3.5 sensor, How get radiometric data

Started by mcq, January 31, 2025, 12:15:36 PM

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mcq

I would like to know how to get the temperature for each pixel of an image from the Anafi Thermal UAV using a Flir Lepton 3.5 sensor.  I would like the lat, long, elevation and temp for each pixel in either a new image format (tiff or jpeg) or a csv file with each row being a pixel.  I have attached an image.

Is this possible?

Phil Harvey

The embedded RawThermalImage may be extracted like this:

exiftool -b -W %t.%s -rawthermalimage FILE

The output will be a file named "RawThermalImage.png" containing a thermal map.

Unfortunately I think the image data in this PNG is stored in the wrong byte order, so you will have to byte-swap it then map it into the recorded temperature range to get a temperature for each pixel.

- Phil

Edit: For reference, here is a link to a long discussion about how to get this type of information out of FLIR images.
...where DIR is the name of a directory/folder containing the images.  On Mac/Linux/PowerShell, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).

mcq

The link says it's off limits.  Is it the thread where the person is trying to separate the RGB and thermal videos into separate video streams?

I am not very good with all of the commands. Here is what I entered:

C:\Users\mquilter>C:\exiftool-13.03_64\exiftool.exe -b -W %t.%s -rawthermalimage C:\Users\mquilter\Desktop\P3190767.JPG
Output file RawThermalImage.png already exists for C:/Users/mquilter/Desktop/P3190767.JPG
    1 image files read
    1 files could not be read
    0 output files created

I ran again with "-rawthermalimage" changed to "-rawthermalimage2".  The return was 0 files created.


Phil Harvey

Sorry.  You should be able to access that post now.

If you run the command twice, you'll get that error the second time because the output file already exists.  It will exist in the current working directory.  Use the "cwd" command to see what that directory is.

- Phil
...where DIR is the name of a directory/folder containing the images.  On Mac/Linux/PowerShell, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).