Why is the long-wave infrared system suitable for detecting targets at room temperature (primarily t

        The total radiation emitted by the target in the mid-wave infrared and long-wave infrared bands can be obtained by integrating the Planck formula. At different temperatures of the target, the total infrared radiation in the medium-wave and long-wave bands is shown in the left figure below; the ratio of the total infrared radiation of the two to the target temperature change is shown in the right.

         It can be seen from the figure that when the temperature of the target is lower than 575K, the long-wave infrared radiation is stronger than the medium-wave infrared radiation, especially when the temperature is around 300K, the long-wave radiation energy is nearly 20 times that of the medium-wave radiation