In addition to the visible light images we are familiar with, objects in the nature also have an infrared thermal radiation image, but the human eye cannot see the infrared thermal radiation. This is because it emits infrared light, which is invisible light. Now, a magic technology called "infrared thermal imaging" can convert the thermal radiation image into a visible light image, which allows people to see things they could not see in the past. The device that realizes this conversion is called thermal imager. Through this thermal imager, we can see a scene like heaven in the night of paint and ink. Now let's see how the thermal imager completes this conversion. The optical mechanical scanner file decomposes the thermal radiation image of the scene received by the Red Space Telescope into thermal radiation signals and focuses them on the infrared detector. The detector and the image video system together amplify and convert the thermal radiation signals into video signals, and people can see magical pictures through the display. The thermal imager can identify small differences in temperature within one percent centigrade. Thermal imaging technology is based on the fact that all objects are heated. Although many objects can not be seen from the outside, they are still hot and cold. With the help of the colors on the heat map, we can see the temperature distribution. Red and pink indicate higher temperatures, while blue and green indicate lower temperatures