Road monitoring license plate recognition system has a lot of problems

The license plate recognition technology refers to a technology that can detect vehicles on the monitored road surface and automatically extract vehicle license plate information (including Chinese characters, English letters, Arabic numerals, and number plate colors) for processing. The license plate recognition is one of the important components in the modern intelligent transportation system and it is widely used. Based on digital image processing, pattern recognition, computer vision and other technologies, it analyzes the images or video sequences of the vehicles captured by the camera to obtain the unique license plate number of each vehicle, thereby completing the recognition process. However, for the identification of detailed road license plates, there are four major problems that need urgent solution.

License plate positioning and character segmentation refers to determining the position of the license plate in the captured image, extracting the image of the license plate, and then segmenting the characters in the license plate. The difficulty in localization of the license plate area mainly comes from the collected images. Due to the diversity of the license plate images collected, and when the images are collected, it is affected by many factors, such as rain, fog, and light, resulting in some license plate image quality appearing to varying degrees. The difference, under normal circumstances, the background of the collected images is very complex, the captured image is a picture collected in high-speed motion, so the location of the license plate in the picture is not fixed, the size of the license plate is not the same, all of the above interference factors are The license plate area positioning and character segmentation brought difficulties, thus affecting the license plate recognition rate.

Contradictions between high resolution and recognition speed, from analog cameras to high-definition cameras, can also cause problems with high resolution and speed of recognition of images. The advantages of HD are self-evident, but everything is two-sided. When the license plate recognition is mainly reflected: HD pictures due to the wide coverage of the picture may appear in the picture at the same time a number of license plate recognition. This requires high speed for license plate recognition. The license plate recognition system may cause excessive processing flow for high-definition video streaming, and it may also cause problems due to the excessively high demand for the identification system resources. Leakage phenomenon, and it is difficult to achieve the accuracy of the vehicle capture rate and license plate recognition.

The adaptability of the license plate recognition system urgently needs to be strengthened. At present, the license plate recognition products in our country all require that the size of the identified license plate is fixed, while the license plates that are too large and too small can not be accurately identified. This poses the problem that some license plates cannot be identified in the event of video triggering. In addition, in some field environments, due to the influence of external conditions, the camera can not be set in the most reasonable position, which will cause the license plate in the picture to shift to different degrees.

The license plate recognition system does not have good recognition of defaced license plates. During the actual application process in highways and cities, it is difficult to ensure that the involved license plates are not defaced. After a license plate is used for several years, contamination and pollution are inevitable. Wear and other phenomena, but the vehicle driving on the road is also very difficult to guarantee that all are standard clean license plates, so in the actual environment, in the face of damaged old license plates, how to improve the recognition capabilities of the license plate recognition system is also a problem that needs to be solved. .