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http://dx.doi.org/10.9708/jksci.2022.27.04.019

A Robust Real-Time License Plate Recognition System Using Anchor-Free Method and Convolutional Neural Network  

Kim, Dae-Hoon (Dept. of Computer Science and Engineering, Kangwon National University)
Kim, Do-Hyeon (Department of Research and Development, ZIOVISION Co. Ltd)
Lee, Dong-Hoon (Department of Research and Development, ZIOVISION Co. Ltd)
Kim, Yoon (Dept. of Computer Science and Engineering, Kangwon National University)
Abstract
With the recent development of intelligent transportation systems, car license plate recognition systems are being used in various fields. Such systems need to guarantee real-time performance to recognize the license plate of a driving car. Also, they should keep a high recognition rate even in problematic situations such as small license plates in low-resolution and unclear image due to distortion. In this paper, we propose a real-time car license plate recognition system that improved processing speed using object detection algorithm based on anchor-free method and text recognition algorithm based on Convolutional Neural Network(CNN). In addition, we used Spatial Transformer Network to increase the recognition rate on the low resolution or distorted images. We confirm that the proposed system is faster than previously existing car license plate recognition systems and maintains a high recognition rate in a variety of environment and quality images because the proposed system's recognition rate is 93.769% and the processing speed per image is about 0.006 seconds.
Keywords
License Plate Recognition; Real-Time; Anchor-Free Method; CNN; Deep Learning;
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1 A. Graves, S. Fernandez, F. Gomez, and J. Schmidhuber. "Connectionist temporal classification: labelling unsegmented sequence data with recurrent neural networks" 23rd international conference on Machine learning, pp. 369-376, June. 2006. DOI: 10.1145/1143844.1143891   DOI
2 Sang-Won Lee, BumSuk Choi, and Yoo-Sung Kim. "A Vehicle License Plate Detection Scheme Using Spatial Attentions for Improving Detection Accuracy in Real-Road Situations" Journal of the Korea Society of Computer and Information, Vol. 26, No.1, pp. 93-101, Jan. 2021. DOI: 10.9708/jksci.2021.26.01.093   DOI
3 Jae-Jung Kim, Chang-Bok Kim. "Implementation of Robust License Plate Recognition System using YOLO and CNN" Journal of KIIT, Vol. 19, No.4, pp. 1-9, Apr. 2021. DOI: 10. 14801/jkiit.2021.19.4.1   DOI
4 H. Law, J. Deng. "Cornernet: Detecting Objects as Paired Keypoints" European Conference on Computer Vision, pp. 734-750, Sep. 2018, DOI: 10.1007/978-3-030-01264-9_45   DOI
5 K. Duan, S. Bai, et al. "Centernet: Keypoint Triplets for Object Detection" IEEE International Conference on Computer Vision, pp. 6569-6578, Nov. 2019. DOI: 10.1109/ICCV.2019.00667   DOI
6 Jong-Woo Han, Yoon Kim. "Vehicle License Plate Recognition Using Neural Networks and Android Deviced" Journal of The Korea Society of Computer and Information, Vol. 23, No. 2, pp. 41-44, Jul. 2015.
7 Jung-Hwan Kim, Joonhong Lim. "License Plate Detection and Recognition Algorithm using Deep Learning" Journal of The Institute of Korean Electrical and Electronics Engineers, Vol. 23, No. 2, pp. 642-651, June. 2019. DOI: 10.7471/ikeee.2019. 23.2.642   DOI
8 Byounghyun Kim, Youngjoon Han, and Hernsoo Hahn. "Robust Scheme of Segmenting Characters of License Plate on Irregular Illumination Condition" Journal of The Korea Society of Computer and Information, Vol. 14, No. 11, pp. 61-71, Nov. 2009.   DOI
9 Y. Zou, et al. "A Robust License Plate Recognition Model Based on Bi-LSTM" IEEE Access, Vol. 8, pp. 211630-211641, Nov. 2020. DOI: 10.1109/ACCESS.2020.3040238   DOI
10 S. Usmankhujaev, S. W. Lee, and J. W. Kwon. "Korean License Plate Recognition System Using Combined Neural Networks" International Symposium on Distributed Computing and Artificial Intelligence, pp. 10-17, June. 2019. DOI: 10.1007/978-3-030-23887-2_2   DOI
11 Z. Ge, S. Liu, et al. "Yolox: Exceeding yolo series in 2021" arXiv preprint arXiv:2107.08430 Jul. 2021.
12 S. Zherzdev, A. Gruzdev. "LPRNet: License Plate Recognition via Deep Neural Networks" arXiv preprint arXiv:1806.10447 June. 2018.
13 AI-Hub, https://aihub.or.kr/aidata/27727
14 M. Jaderberg, K. Simonyan, A. Zisserman, and K. Kavukcuoglu. "Spatial Transformer Networks" Advances in Neural Information Processing Systems, Vol 2, pp. 2017-2025, Dec. 2015. DOI: 10.5555/2969442.2969465   DOI
15 B. Shi, X. Bai, and C. Yao. "An End-to-End Trainable Neural Network for Image-based Sequence Recognition and Its Application to Scene Text Recognition" IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol. 39, No. 11, pp. 2298-2304, Nov. 2017. DOI: 10.1109/TPAMI.2016.2646371   DOI
16 C. Wang, I. Yeh, and H. Liao. "You only learn one representation: Unified network for multiple tasks" arXiv preprint arXiv:2105.04206 May. 2021.
17 I. Goodfellow, J. Pouget-Abadie, et al. "Generative Adversarial Nets" Advances in Neural Information Processing Systems, Vol. 2, pp. 2672-2680, Dec. 2014. DOI: 10.5555/2969033.2969125   DOI
18 Jin-Ho Kim. "Distortion Invariant Vehicle License Plate Extraction and Recognition Algorithm" Journal of the Korea Contents Association, Vol. 11, No. 3, pp. 1-8, March. 2011. DOI: 10.5392/JKCA.2011.11.3.001   DOI
19 Dongwook Min, Hyunseok Lim, and Jeonghwan Gwak. "Improved Method of License Plate Detection and Recognition Facilitated by Fast Super-Resolution GAN" Korean Institute of Smart Media, Vol. 9, No. 4, pp. 134-143, Dec. 2020. DOI: 10.30693/smj.2020.9.4.134   DOI
20 W. Liu, D. Anguelov, et al. "SSD: Single Shot MultiBox Detector" European Conference on Computer Vision, pp. 21-37, Dec. 2016. DOI: 10.1007/978-3-319-46448-0_2   DOI
21 S. Hochreiter, J. Schmidhuber. "Long Short-Term Memory" Neural Computation, Vol. 9, No. 8, pp. 1735-1780, Nov. 1997. DOI: 10.1162/neco.1997.9.8.1735   DOI
22 J. Redmon, A. Farhadi. "YOLO9000: Better, Faster, Stronger" IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pp. 6517-6525, Jul. 2017. DOI: 10.1109/CVPR.2017.690   DOI
23 Chang, I.-S., and Park, G. "Improved Method License Plate Detection and Recognition using Synthetic Number Plate" Journal of Broadcast Engineering, Vol. 26, No. 4, pp. 453-462, Jul. 2021. DOI: 10.5909/JBE.2021.26.4.453   DOI