Real-time license plate recognition method based on deep learning in complex scene

Abstract

The invention provides an automatic license plate recognition method in a natural scene based on a deep learning technology. The basic principle is as follows: firstly, using a lightweight MobileNet neural network as a feature extraction network, adding the feature extraction network to a deep learning object detection algorithm SSD (Signal Shot Multi-boxes Detector), and training on a scene license plate image; then, detecting a license plate region by utilizing SSD-MobileNet and classifying the types of license plates; secondly, for the detected license plate area, determining a boundary point set by searching for character contours through multi-threshold binarization operation, performing line fitting on the boundary point set to determine license plate corner points, and correcting the license plate in one step through perspective transformation operation; and finally, sending the license plate to a convolutional neural network with seven outputs to obtain all license plate character outputs. Compared with an existing license plate recognition algorithm, the license plate detection and positioning correction algorithm based on the deep learning technology is faster and more accurate, and the method has robustness on license plate detection under complex natural scene. The system does not need character segmentation operation, feature transmission loss is reduced, the recognition speed is greatly increased through the end-to-end recognition network under the condition that the accuracy is guaranteed, the whole system can achieve the real-time license plate recognition effect, and the practical value is achieved.

Description

technical field [0001] The invention belongs to the fields of image processing technology and text recognition, and relates to an automatic recognition method of license plates in complex scenes realized by using deep learning technology. Background technique [0002] The number of motor vehicles in my country is increasing year by year, which puts forward higher requirements for the management of traffic vehicles. Under this background, the intelligent traffic and monitoring system came into being. Automatic Vehicle License Plate Recognition (ALPR) plays a very important role in intelligent traffic and monitoring systems. This technology has a wide range of application scenarios, such as parking lot access control, road traffic monitoring, future unmanned traffic Wait. The main purpose of ALPR is to locate the license plate area from the scene, extract the license plate character information, and finally recognize the license plate characters. The classic ALPR system proce...

AI Technical Summary

Problems solved by technology

[0007] In order to solve the existing ALPR system's insufficient recognition ability in complex scenes, limited types of license plate recognition, and information loss an

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