Cover
Vol. 21 No. 1 (2025)

Published: September 19, 2025

Pages: 210-220

Original Article

License Plate Detection and Recognition in Unconstrained Environment Using Deep Learning

Abstract

Real-time detection and recognition systems for vehicle license plates present a significant design and implementation challenge, arising from factors such as low image resolution, data noise, and various weather and lighting conditions.This study presents an efficient automated system for the identification and classification of vehicle license plates, utilizing deep learning techniques. The system is specifically designed for Iraqi vehicle license plates, adapting to various backgrounds, different font sizes, and non-standard formats. The proposed system has been designed to be integrated into an automated entrance gate security system. The system’s framework encompasses two primary phases: license plate detection (LPD) and character recognition (CR). The utilization of the advanced deep learning technique YOLOv4 has been implemented for both phases owing to its adeptness in real-time data processing and its remarkable precision in identifying diminutive entities like characters on license plates. In the LPD phase, the focal point is on the identification and isolation of license plates from images, whereas the CR phase is dedicated to the identification and extraction of characters from the identified license plates. A substantial dataset comprising Iraqi vehicle images captured under various lighting and weather circumstances has been amassed for the intention of both training and testing. The system attained a noteworthy accuracy level of 95.07%, coupled with an average processing time of 118.63 milliseconds for complete end-to-end operations on a specified dataset, thus highlighting its suitability for real-time applications. The results suggest that the proposed system has the capability to significantly enhance the efficiency and reliability of vehicle license plate recognition in various environmental conditions, thus making it suitable for implementation in security and traffic management contexts.

References

  1. M. Sarfraz, M. J. Ahmed, and S. A. Ghazi, “Saudi ara- bian license plate recognition system,” in 2003 Interna- tional Conference on Geometric Modeling and Graphics, 2003. Proceedings, pp. 36–41, IEEE, 2003.
  2. M. Ahmed, M. Sarfraz, A. Zidouri, and W. Al-Khatib, “License plate recognition system,” in 10th IEEE Interna- tional Conference on Electronics, Circuits and Systems, 2003. ICECS 2003. Proceedings of the 2003, vol. 2, pp. 898–901 Vol.2, 2003.
  3. R. Laroca, E. Severo, L. A. Zanlorensi, L. S. Oliveira, G. R. Gonc¸alves, W. R. Schwartz, and D. Menotti, “A ro- bust real-time automatic license plate recognition based on the yolo detector,” in 2018 international joint confer- ence on neural networks (ijcnn), pp. 1–10, IEEE, 2018.
  4. R. Laroca, L. Zanlorensi, G. Gonc¸alves, E. Todt, W. Schwartz, and D. Menotti, “An efficient and layout- independent automatic license plate recognition system based on the yolo detector. arxiv 2019,” arXiv preprint arXiv:1909.01754.
  5. S. Yonetsu, Y. Iwamoto, and Y. W. Chen, “Two-stage yolov2 for accurate license-plate detection in complex scenes,” in 2019 IEEE International Conference on Con- sumer Electronics (ICCE), pp. 1–4, IEEE, 2019.
  6. Z. Liu, Z. Wang, and Y. Xing, “Wagon number recogni- tion based on the yolov3 detector,” in 2019 IEEE 2nd in- ternational conference on computer and communication engineering technology (CCET), pp. 159–163, IEEE, 2019.
  7. A. R. Youssef, A. A. Ali, and F. R. Sayed, “Real-time egyptian license plate detection and recognition using yolo,” International Journal of Advanced Computer Sci- ence and Applications, vol. 13, no. 7, 2022.
  8. V. Jain, Z. Sasindran, A. Rajagopal, S. Biswas, H. S. Bharadwaj, and K. Ramakrishnan, “Deep automatic li- cense plate recognition system,” in Proceedings of the Tenth Indian Conference on Computer Vision, Graphics and Image Processing, pp. 1–8, 2016.
  9. M. Al-Yaman, H. Alhaj Mustafa, S. Hassanain, A. Abd AlRaheem, A. Alsharkawi, and M. Al-Taee, “Improved automatic license plate recognition in jordan based on ceiling analysis,” Applied Sciences, vol. 11, no. 22, p. 10614, 2021.
  10. C. Gou, K. Wang, Y. Yao, and Z. Li, “Vehicle license plate recognition based on extremal regions and re- stricted boltzmann machines,” IEEE transactions on in- telligent transportation systems, vol. 17, no. 4, pp. 1096– 1107, 2015.
  11. Q. Wang, “License plate recognition via convolutional neural networks,” in 2017 8th IEEE International Con- ference on Software Engineering and Service Science (ICSESS), pp. 926–929, IEEE, 2017. 220 | Hakim, Alhakeem, Al-Musawi, Al-Ibadi & Al-Ibadi
  12. S. M. Silva and C. R. Jung, “License plate detection and recognition in unconstrained scenarios,” in Proceedings of the European conference on computer vision (ECCV), pp. 580–596, 2018.
  13. G. Y. Abbass and A. F. Marhoon, “Iraqi license plate detection and segmentation based on deep learning,” Iraqi Journal for Electrical and Electronic Engineer- ing, vol. 17, no. 2, pp. 102–107, 2021.
  14. Y. Elhadi, O. Abdalshakour, and S. Babiker, “Arabic- numbers recognition system for car plates,” in 2019 International Conference on Computer, Control, Electri- cal, and Electronics Engineering (ICCCEEE), pp. 1–6, IEEE, 2019.
  15. I. R. Khan, S. T. A. Ali, A. Siddiq, M. M. Khan, M. U. Ilyas, S. Alshomrani, and S. Rahardja, “Automatic li- cense plate recognition in real-world traffic videos cap- tured in unconstrained environment by a mobile camera,” Electronics, vol. 11, no. 9, p. 1408, 2022.
  16. S. R. Ahmed, M. R. Ahmed, D. A. Majeed, A. H. Hammed, A. salam Daham, and E. H. Hammed, “An- droid application to retrieve car details from car plate numbers,” in IOP Conference Series: Materials Science and Engineering, vol. 928, p. 032026, IOP Publishing, 2020.
  17. M. Shehata, M. T. Abou-Kreisha, and H. Elnashar, “Deep machine learning based egyptian vehicle li- cense plate recognition systems,” arXiv preprint arXiv:2107.11640, 2021.
  18. D. Habeeb, F. Noman, A. A. Alkahtani, Y. A. Alsariera, G. Alkawsi, Y. Fazea, A. M. Al-Jubari, et al., “Deep- learning-based approach for iraqi and malaysian vehicle license plate recognition,” Computational intelligence and neuroscience, vol. 2021, 2021.
  19. R. Antar, S. Alghamdi, J. Alotaibi, and M. Alghamdi, “Automatic number plate recognition of saudi license car plates,” Engineering, Technology & Applied Science Research, vol. 12, no. 2, pp. 8266–8272, 2022.
  20. A. R. Youssef, A. A. Ali, and F. R. Sayed, “Real-time egyptian license plate detection and recognition using yolo,” International Journal of Advanced Computer Sci- ence and Applications, vol. 13, no. 7, 2022.
  21. H. H. Yaba and H. O. Latif, “Plate number recognition based on hybrid techniques,” UHD Journal of Science and Technology, vol. 6, no. 2, pp. 39–48, 2022.
  22. C. Henry, S. Y. Ahn, and S.-W. Lee, “Multinational license plate recognition using generalized character sequence detection,” IEEE Access, vol. 8, pp. 35185– 35199, 2020.
  23. A. Bochkovskiy, C.-Y. Wang, and H.-Y. M. Liao, “Yolov4: Optimal speed and accuracy of object detec- tion,” arXiv preprint arXiv:2004.10934, 2020.
  24. C.-Y. Wang, H.-Y. M. Liao, Y.-H. Wu, P.-Y. Chen, J.-W. Hsieh, and I.-H. Yeh, “Cspnet: A new backbone that can enhance learning capability of cnn,” in Proceedings of the IEEE/CVF conference on computer vision and pattern recognition workshops, pp. 390–391, 2020.
  25. K. He, X. Zhang, S. Ren, and J. Sun, “Spatial pyra- mid pooling in deep convolutional networks for visual recognition,” IEEE transactions on pattern analysis and machine intelligence, vol. 37, no. 9, pp. 1904–1916, 2015.
  26. S. Liu, L. Qi, H. Qin, J. Shi, and J. Jia, “Path aggregation network for instance segmentation,” in Proceedings of the IEEE conference on computer vision and pattern recognition, pp. 8759–8768, 2018.
  27. J. Redmon and A. Farhadi, “Yolov3: An incremental improvement,” arXiv preprint arXiv:1804.02767, 2018.
  28. H. Hakim and A. Fadhil, “Survey: Convolution neural networks in object detection,” in Journal of Physics: Conference Series, vol. 1804, p. 012095, IOP Publishing, 2021.
  29. J. Zhuang, S. Hou, Z. Wang, and Z.-J. Zha, “Towards human-level license plate recognition,” in Proceed- ings of the European Conference on Computer Vision (ECCV), pp. 306–321, 2018.
  30. G. R. Gonc¸alves, M. A. Diniz, R. Laroca, D. Menotti, and W. R. Schwartz, “Real-time automatic license plate recognition through deep multi-task networks,” in 2018 31st SIBGRAPI conference on graphics, patterns and images (SIBGRAPI), pp. 110–117, IEEE, 2018.
  31. H. Li and C. Shen, “Reading car license plates using deep convolutional neural networks and lstms. arxiv 2016,” arXiv preprint arXiv:1601.05610.
  32. H. Li, P. Wang, and C. Shen, “Toward end-to-end car license plate detection and recognition with deep neural networks,” IEEE Transactions on Intelligent Transporta- tion Systems, vol. 20, no. 3, pp. 1126–1136, 2018.