trigger mode of license plate recognition system < / a >

　　1. Peripheral coil trigger

The trigger mode of peripheral coil refers to that the coil, infrared or vehicle detector are used to pass the signal. After receiving the vehicle trigger signal, the license plate recognition system collects the vehicle and license plate image, and automatically recognizes the license plate for subsequent processing. The advantages of this method are high trigger rate and stable performance; The disadvantage is that it needs to cut the ground and lay the coil, which has a large amount of construction

　　2. Video trigger mode

Video trigger means that the license plate recognition system adopts the dynamic moving target sequence image analysis and processing algorithm technology to detect the movement of vehicles on the lane in real time, capture the vehicle image when the vehicle is found to pass, recognize the vehicle license plate and carry out subsequent processing. The video trigger mode does not need the help of coil, infrared or other hardware vehicle detector. This method has the advantages of convenient construction, no need to cut the ground to lay the coil, and no need to install vehicle detector and other parts, but its disadvantages are also very significant. Due to the reason of the algorithm, the trigger rate and recognition rate of this scheme are much lower than that of the external coil trigger