1. The first speed camera is a rectangular box, and the radar module connected to it plays a decisive role. When the radar detects that the vehicle is speeding, it will link the camera to take photos for evidence collection. The principle of velocity measurement radar using Doppler effect. When the vehicle approaches the radar antenna, the frequency of the reflected signal will be higher than that of the transmitter. When the vehicle leaves the antenna, the frequency of the reflected signal will be lower than the transmission probability. In this way, by changing the frequency value, the relative speed between the target and the radar can be calculated;
2. The second is the security bayonet camera. When citizens drive past this camera, they often find that they will flash their lights to take pictures regardless of the speed. In fact, there is no need to panic in this situation. Its main function is to monitor the vehicles and personnel at the entrance and exit, check the clues of suspicious vehicles, and help the staff of criminal police and other departments to trace the people involved. There is no obvious difference in appearance between this camera and the speed measuring camera;
3. The third type is surveillance cameras, which are spherical, cylindrical, square box-shaped and so on. Some of these cameras are equipped with LED lighting devices, which are kept on at night to ensure a clear view of the cameras. The main purpose of setting up these cameras is to apply all kinds of captured information to public security prevention and control, identify the facts of the case according to the image records, and lock or even capture all kinds of criminal suspects.
Million car purchase subsidy