Analyzing images from a drone acquired using FLIR TAU2 camera

[Tanya]

Hello All,
I am thinking of the best and easy way to analyze 1000 images acquired using Tau2 640 camera from a drone (One sample image is attached). I tried to get the raw image and use the equations in the exiftool forum to convert it to temperature but I had no success with that, I am using matlab to view the images and do the image stitching but my main goal is to have something from the images like temperature and correct them for atmospheric conditions. Any suggestions would be helpful? Thank you.

[tmbinc]

The image you attached is an 8-bit image, i.e. the 14-bit raw data has already been converted to 8-bit, likely by either linear mapping or histogram equalization (or a mix of the two). Unless you happen to have the meta-information to recover the original histogram, there's no way to recover the temperature, as there's no information of what "white" and "black" corresponds to.

The 14-bit data can either be "radiometric flux" or "TLinear" (see https://www.flir.com/globalassets/imported-assets/document/tau2_product_specification.pdf), and the computations are different depending on the mode.

[railrun]

Can you tell me how you record the images?

[Tanya]

Hello All,
Thank you for your reply, I have no idea how the images were recorded, I just got the images from my colleague last week and there were not processed by any software and they have no metadata which I checked using exiftool. The only thing I know that the images are acquired using Tau 2 640*514 resolution mounted on a drone. I think there should be an option to get another format of the images from Tau2, not sure and still need to check.

Currently, I am thinking of a"not very accurate method" to get temperature is through taking some reference temperature measurements on ground and relate them somehow to intensity appeared in the images (0-255) and then apply regression equation for the whole image to get values of temperature per pixel  .

[Bud]

I do not have a TAU2 but i'd check the camera configuration. It may have an option to store raw thermal images separately from visual ones. Even the consumer level E4 has that option.