Electronic Science and Technology ›› 2023, Vol. 36 ›› Issue (10): 1-8.doi: 10.16180/j.cnki.issn1007-7820.2023.10.001

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Chinese License Plate Detection and Recognition in Unconstrained Scenarios Based on YOLO

CHEN Ziang1,LIU Na1,YUAN Ye2,LI Qingdu3,WAN Lihong4   

  1. 1. School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093,China
    2. School of Electronics, Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200093,China
    3. School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093,China
    4. Origin Dynamics Intelligent Robot Co.,Ltd., Zhengzhou 450018,China
  • Received:2022-05-05 Online:2023-10-15 Published:2023-10-20
  • Supported by:
    National Natural Science Foundation of China(61773083);Pujiang Talent Program of Shanghai(2019PJD035)

Abstract:

In view of the problems of traditional Chinese license plate recognition methods, such as the requirement of scenes, poor real-time performance, and inability to deploy on edge devices, this study proposes a Chinese license plate detection and recognition method based on YOLO(You Only Look Once) in unconstrained scenes. This method is divided into two modules: license plate detection and license plate character recognition. In the license plate detection part, the improved YOLOv5 model is used to predict four groups of key points for license plate correction based on the prediction of target candidate regions, and the pre-training model trained on the COCO data set is used for training, which reduces the error detection problem caused by the complex environment and has high real-time performance. In the license plate character recognition part, the CRNN(Convolutional Recurrent Neural Network) model is improved, which greatly reduces the parameters and computation of the algorithm, so that it can be successfully deployed in various edge devices. Experimental results show that the proposed method can efficiently detect and recognize license plates in complex environments. The map value of the proposed license plate detection model is 3.0% higher than that of Retina-face in the license plate detection data set. Compared with LPR-Net, the accuracy of license plate character recognition model in license plate recognition data set is improved by 4.2%.

Key words: license plate detection, license plate recognition, neural network, deep learning, character recognition, object detection, data set, wing loss

CLC Number: 

  • TP183