> At this point, I realized that I got the "V2" of the camera. This camera is regarded as worse than the "V1" mostly because the manufacturer removed the intern

> At this point, I realized that I got the "V2" of the camera. This camera is regarded as worse than the "V1" mostly because the manufacturer removed the internal processing FPGA? That's actually better. In-camera processing will just reduce the amount of information you can get out of the sensor. For example, even if it does exactly the same flat-fielding as you do, the in-camera flat-fielded image has to be requantized to 8-bit format before sending to the computer, therefore losing precision. You can get even better accuracy by taking a dark or bias field (might be possible if you can set the exposure time to something very short, but this might not be possible with these thermographic cameras) and taking flatfields at different temperatures, so you can get per-pixel linearity curves. That's a lot of work though, and ideally each camera was indiviually calibrated by the producer, but I am guessing that is not done for these cheap cameras.