The Retinex theory holds that the color of an object is determined by the object's ability to reflect different wavelengths. The object has color consistency, and whether the illumination is uniform or not does not affect the color of the object.

 

Thermal infrared images belong to grayscale images. Although the imaging mechanism is different from that of visible light images, it can be assumed that the infrared radiation emitted by an object is the reflection of infrared light by an object under the irradiation of an infrared light source. It is formed by the infrared light reflected by the object, so the Retinex theory is also suitable for processing thermal infrared images, but there is only one color channel during processing, which is different from the three color channels of color images.