The optical system collects the infrared radiation emitted by the scene, and after optical filtering, the radiant energy distribution of the scene is concentrated on the photosensitive surface of the detector located on the focal plane of the optical system. The optomechanical scanner includes two scanning mirror groups, one for vertical scanning and one for horizontal scanning. The scanner is located between the focusing optics and the detector. When the scanner works, the beam from the scene to the detector moves with it, sweeping out a television-like grating in the object space. When the scanner sweeps the detector across the scene in the form of a television grating, the detector receives the radiation of the scene point by point and converts it into a corresponding electrical signal. In other words, the image of the scene formed by the optical-mechanical scanner scans the detector in turn, and the detector converts the infrared radiation of each part of the scene into electrical signals in turn. After video processing, the signal is displayed on the synchronously scanned display. . The figure below shows the working principle of the simplest opto-mechanical scanning infrared imaging system.