Not the output of the app, not even their LUT, got a grey scale image of my hand and noticed that I could see my veins, so I post processed it to get the highest contrast I could, but didn't do a lot of processing, some mild despeckle and contrast adjustment.
Then since I still had the app running I measured the hotter spot and the cooler spot visually and added the values to the image.
32.894 C is the maximum but rounded up to 33, the next highest value was 32.851 C so the step at that range is just 0.043 K on other spots I saw the deltas being 0.044 K increments but didn't analyze it with the data, just moving my cursor around for now.
the maximum integer value was 2819 and the other one was 2817 but I seen those values on other areas of the image so it seems the temperature data is averaged, so the integer values might be unprocessed.
The lower value is 24.478 (2625 int value) but rounded it up to 25 in the picture. Next value near was 24.523 (int value 2626-2628) so it seems the integer has more resolution than what they average for the temperature array for the full image. But still around 0.045 K deltas on the temperature array, but it seems the sensors are 4 times more accurate than that.
Sorry for mixing Celsius for absolutes and Kelvin for deltas.
Also I see vertical banding from their algorithm, they seem to go away if I rotate the camera 90 degrees.
My ring is around 28 C at its coldest spot.
Sorry if I didn't alter the program more to get more accurate values and deltas, but I only have time to play with it for now.
Here is the original pre-processed image. One thing is that if you stop the camera you can still look at the per pixel values with the mouse of the last captured image, pretty handy (no pun intended).