'Mapping pixel color to temperature value on thermal image

I have some thermal images with a temperature scale associated. I'm trying to get for each temperature value the corresponding pixel color.

I've isolated the scales and obtained some jpg files like this one :

The final goal is to find any hot spot with a temperature value higher than 80°, so I can focus only on max values of each scale.

This is an example of my whole image.

scale temperature

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Solution	Source