Thermal cameras measure the apparent surface temperature of a given object. This is done by taking the amount of infrared radiation an object emits and calculating the surface temperature by applying a formula that adjusts for external factors. This struct includes all of the external scene parameters that the thermal camera firmware allows to be customized. There are two types of parameters, optical parameters which specify how much infrared radiation is transmitted from the surface to the thermal sensor, as well as parameters that specify sources of thermal radiance other than the object. For a more in-depth overview of the physics behind thermal imaging, see https://en.wikipedia.org/wiki/Thermography.