At present, automatic license plate recognition parking system is more and more widely used in smart parking systems. Automatic license plate recognition is an automatic pattern recognition technology that uses dynamic video or static images of vehicles to perform license plate number and license plate color. A complete license plate recognition system should include several parts such as vehicle detection, image acquisition, and license plate recognition.
When the vehicle detection part detects the arrival of the vehicle, the image acquisition unit is triggered to acquire the current video image. The license plate recognition unit processes the image, locates the position of the license plate, and then separates the characters in the license plate for recognition, and finally composes the license plate number output. Currently, there are three main application modes of license plate recognition in parking lot management systems: video recognition mode, ground sensing coil recognition mode, and video + ground sensing recognition mode.
Video recognition mode
The advantage of video triggering is that there is no need to install ground-sensing coils and the amount of engineering is small. When the vehicle enters the video recognition area, the camera automatically recognizes the license plate information through the dynamic image of the vehicle, and provides simulation trigger recognition. The disadvantage is that images cannot be output for unlicensed cars; if the license plate result is not recognized, you can manually click the simulation trigger to recognize.
2. Ground induction coil recognition mode Ground induction coil is triggered.
Under normal circumstances, there will be a deceleration belt about 10 meters in front of the barrier of the parking lot. The vehicle will slow down through the deceleration band to allow time for the recognition of the license plate. The vehicle enters the recognition area and triggers the ground induction coil. Automatically take a snapshot, recognize the license plate, and let the barrier pass. The advantage of ground-sensing coil triggering license plate recognition lies in its practical and stable performance, and can output image records for unlicensed vehicles. The disadvantage is that it requires construction and installation, and the amount of work is large.
3. Video + ground sense recognition mode
This method is an upgraded version of the first two modes. The video plus ground sense recognition mode is recognized through video recognition and uploaded through ground sense triggering. Compared with the ground sensing coil recognition and the video recognition mode, the video + ground sensing recognition mode can provide faster recognition speed and higher recognition rate. It is the recognition mode with the best application flexibility at present. The recognition area and output are defined by software Area, according to the customer's site environment, freely set the location of the license plate output.
