Extracting thermal information from Mavic 2 camera (FC2403)

[sebastianbarria]

Hi everyone.
I've worked before extracting thermal information from thermal images (using Thomas123's flir.php file) and everything worked fine until I start using the Mavic camera.
The problem is that it shows (on the controller's screen) the thermal information and the min/max temperatures, but the exported file looks like a simple JPG file that looks like a thermal image.

So, what I did is to configure the camera to use the grayscale pallette (assuming that 100% back  is the lowest temperature and 100% white is the higher temperature) and configure the camera sensors to work with the -10-140 celcius degrees of temperature.

With that (and assuming that the grayscale is a linear scale from balck to white), I just did simple maths to calculate the estimated temperatures from the image.
That's a good approach, but it looks like the camera doesn´t export the image considering -10°C as 100% black and 140°C as 100% white; it exports considering 100% black as the lowest temperature in the current image and 100% white as  the higher. So, my problem is that the min and max temperature varies in each image.

I tried looking into the metadata for a clue of the min and max temperatures, but I had no luck. And, of course, other values, like planck are not present.

Does any of you have solved this problem or had an idea of how to resolve it?
Any help would be appreciate.
Thanks!

PS: I'm attaching an example of "thermal" image captured with Mavic 2 enterprise dual camera

[Phil Harvey]

The maker notes in this image are not what ExifTool expects from a DJI camera, and isn't decoding them properly.

However, scanning through them by hand I don't see any useful information, just a few headings and no real data.

So I can't see where the min/max temperatures could be stored.

It is odd that the file contains a PreviewImage that is essentially the same as the main image as far as I can tell -- there is maybe a 1-pixel shift, but the images themselves look about the same.  Any idea about this?

- PHil

[sebastianbarria]

Thanks Phil.
So, as I expected, there's nothing to do with this images... they're trash.
About the preview image, I really don't know.

I asked this same question to the people at DJI, so, if I get an answer from them, I'll post it here.
Thanks!

[Actual Potato]

Hi everyone,

I have a similar requirement needing to extract the temperature values into a CSV file, are there any updates on this?

Any help would be appreciated.
Thanks!

[Phil Harvey]

You want to extract the themal image temperatures to a CSV?  That is an odd format for a 2-dimensional dataset.  But nothing new on this from my end.

- Phil