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A Character Segmentation Method to Increase Character Recognition Accuracy for Turkish License Plates

Received: 19 September 2021    Accepted: 16 October 2021    Published: 31 December 2021
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Abstract

Automatic License Plate Recognition is a computer vision technology that provides a way to recognize the vehicle's license plates without direct human intervention. Developing Automatic License Plate Recognition methodologies is a widely studied topic among the computer vision community to increase the accuracy rates. Automatic License Plate Recognition systems include image acquisition and character segmentation phases. Although there are many studies, the research in character segmentation and improving recognition accuracy remains limited. The lack of an international standard for license plates and the misinterpretation of ambiguous characters are challenging problems for Automatic License Plate Recognition systems. Several academic works have shown that the ambiguous character problem can be overcome by using a second model that contains only these characters. In this study, we propose a new methodology to reduce the character recognition errors of Automatic License Plate Recognition systems. One of the reasons for the low accuracy rates is the problem of ambiguous characters. In most studies using OCR, it was observed that a single model was used for alphanumeric characters during the recognition phase. Instead of using a single model, using separate models for letters and digits will improve the recognition process and increase accuracy. Therefore, we determined whether the characters are letters or numbers, and we expressed the license plates in the form of letters - digits. The method suggested for segmenting blobs worked with an accuracy of 96.12% on the test dataset. The method recommended for generating letter-digit expressions for the license plates worked with an accuracy of 99.28% on the test dataset. The proposed methodology can work only on Turkish license plates. In future studies, we will expand our method by using the license plate dataset of a different country.

Published in Mathematics and Computer Science (Volume 6, Issue 6)
DOI 10.11648/j.mcs.20210606.13
Page(s) 92-104
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

License Plate Recognition, Character Segmentation, Optical Character Recognition, Letter-digit Expression, Image Processing

References
[1] Akhtar, Z., Rashid, A. (2020). Automatic number plate recognition using random forest classifier. SN Computer Science, 1.3, 1-9.
[2] Dalarmelina, N. D. V., Teixeira, M. A., Meneguette, R. I. (2020). A real-time automatic plate recognition system based on optical character recognition and wireless sensor networks for ITS. Sensors, 20 (1), 55.
[3] Businesswire: Deployment of ANPR systems in security and surveillance, and traffic enforcement applications - Research and Markets. Available online: https://www.businesswire.com/news/home/20170822005793/en/Global-Automatic-Number-Plate-Recognition-ANPR-System (accessed on 09 04 2021).
[4] Patel, C., Shah, D., Patel, A. (2013). Automatic number plate recognition system (ANPR): A survey. International Journal of Computer Applications, 69 (9), 21-33.
[5] Galindo J., Castro, C., Braga, A. (2016). Sistema automatico para reconhecimento de placas de automoveis baseado em processamento digital de imagens eredes perceptron de multiplas camadas [Automatic system for recognizing license plates based on digital image processing and network perceptron multiple layers]. In Proceedings of the XIX Encontro Nacional de Modelagem Computacional, 19-21.
[6] Peixoto, S. P., Cámara-Chávez, G., Menotti, D., Gonçalves, G., Schwartz, W. R. (2015). Brazilian license plate character recognition using deep learning. In Proceedings of the XI Workshop de Visão Computacional.
[7] da Silva, F. A., Artero, A. O., de Paiva, M. S. V., Barbosa, R. L. (2012). ALPRs-A new approach for license plate recognition using the SIFT algorithm. VIII Computer Vision Workshop.
[8] Panchal, T., Patel, H., Panchal, A. (2016). License plate detection using Harris corner and character segmentation by integrated approach from an image. Procedia Computer Science, 79, 419-425.
[9] Liu, W. C., Lin, C. H. (2017). A hierarchical license plate recognition system using supervised k-means and support vector machine. International Conference on Applied System Innovation, 1622-1625.
[10] Mahalakshmi, S., Tejaswini, S. (2017). Study of character recognition methods in automatic license plate recognition (ALPR) system. International Research Journal of Engineering and Technology, 4, 1420-1426.
[11] Anagnostopoulos, C. N. E., Anagnostopoulos, I. E., Loumos, V., Kayafas, E. (2006). A license plate recognition algorithm for intelligent transportation system applications. IEEE Transactions on Intelligent transportation Systems, 7 (3), 377-392.
[12] Ozturk, F., Ozen, F. (2012). A new license plate recognition system based on probabilistic neural networks. Procedia Technology, 1, 124. 128.
[13] Zheng, L., He, X., Samali, B., Yang, L. T. (2013). An algorithm for accuracy enhancement of license plate recognition. Journal of Computer and System Sciences, 79 (2), 245-255.
[14] Wen, Y., Lu, Y., Yan, J., Zhou, Z., von Deneen, K. M., Shi, P. (2011). An algorithm for license plate recognition applied to intelligent transportation system. IEEE Transactions on Intelligent Transportation Systems, 12 (3), 830-845.
[15] Pan, M. S., Yan, J. B., Xiao, Z. H. (2008). Vehicle license plate character segmentation. International Journal of Automation and Computing, 5 (4), 425-432.
[16] Lakshmi, C. J., Rani, A. J., Ramakrishna, K. S., Lantikiran, M., Siddhartha, V. (2011). A novel approach for Indian license plate recognition system. International Journal of Advanced Engineering Sciences and Technologies, 6 (1), 010-014.
[17] Kocer, H. E., Cevik, K. K. (2011). Artificial neural networks-based vehicle license plate recognition. Procedia Computer Science, 3, 1033-1037.
[18] Shapiro, V., Gluhchev, G., Dimov, D. (2006). Towards a multinational car license plate recognition system. Machine Vision and Applications, 17 (3), 173-183.
[19] Puranic, A, Deepak, K., Umadevi, V. (2016). Vehicle number plate recognition system: a literature review and implementation using template matching. International Journal of Computer Applications, 134 (1), 12-16.
[20] Chang, S. L., Chen, L. S., Chung, Y. C., Chen, S. W. (2004). Automatic license plate recognition. IEEE Transactions on Intelligent Transportation Systems, 5 (1), 42-53.
[21] Xie, F., Zhang, M., Zhao, J., Yang, J., Liu, Y., Yuan, X. (2018). A robust license plate detection and character recognition algorithm based on a combined feature extraction model and BPNN. Journal of Advanced Transportation.
[22] Deb, K., Khan, I., Saha, A., Jo, K. H. (2012). An efficient method of vehicle license plate recognition based on sliding concentric windows and artificial neural network. Procedia Technology, 4, 812-819.
[23] Badr, A., Abdelwahab, M. M., Thabet, A. M., Abdelsadek, A. M. (2011). Automatic number plate recognition system. Annals of the University of Craiova Mathematics and Computer Science Series, 38 (1), 62-71.
[24] Zhu, Y., Huang, H., Xu, Z., He, Y., Liu, S. (2011). Chinese style plate recognition based on artificial neural network and statistics. Procedia Engineering, 15, 3556-3561.
[25] Sarfraz, M., Ahmed, M. J., Ghazi, S. A. (2003). Saudi Arabian license plate recognition system. International Conference on Geometric Modeling and Graphics, 36-41.
[26] Songke, L., Yixian, C. (2011). License plate recognition.
[27] Zou, Y., Zhang, Y., Yan, J., Jiang, X., Huang, T., Fan, H., & Cui, Z. (2020). A robust license plate recognition model based on bi-LSTM. IEEE Access, 8, 211630-211641.
[28] Pustokhina, I. V., Pustokhin, D. A., Rodrigues, J. J., Gupta, D., Khanna, A., Shankar, K., Joshi, G. P. (2020). Automatic vehicle license plate recognition using optimal K-means with convolutional neural network for intelligent transportation systems. Ieee Access, 8, 92907-92917.
[29] Rahman, R., Pias, T. S., Helaly, T. (2020). GGCS: A Greedy Graph-Based Character Segmentation System for Bangladeshi License Plate. In 2020 4th International Symposium on Multidisciplinary Studies and Innovative Technologies (ISMSIT) (pp. 1-7). IEEE.
[30] Selmi, Z., Halima, M. B., Pal, U., Alimi, M. A. (2020). DELP-DAR system for license plate detection and recognition. Pattern Recognition Letters, 129, 213-223.
[31] Henry, C., Ahn, S. Y., Lee, S. W. (2020). Multinational license plate recognition using generalized character sequence detection. IEEE Access, 8, 35185-35199.
[32] Silva, S. M., Jung, C. R. (2020). Real-time license plate detection and recognition using deep convolutional neural networks. Journal of Visual Communication and Image Representation, 71, 102773.
[33] Namysl, M., Konya, I. (2019). Efficient, lexicon-free OCR using deep learning. International Conference on Document Analysis and Recognition, 295-301.
[34] Automated number plate recognition (ANPR) and detection sensor market report explored in latest research. Available online: https://www.pharmiweb.com/press-release/2020-01-03/automated-number-plate-recognition-anpr-and-detection-sensor-market-report-explored-in-latest-rese (accessed on 09 04 2021).
[35] Turkish license plate dataset. Available online: https://github.com/muratlutfigoncu/turkish-license-plate-detector (accessed on 09 04 2021).
Cite This Article
  • APA Style

    Gulsum Cigdem Cavdaroglu, Mehmet Gokmen. (2021). A Character Segmentation Method to Increase Character Recognition Accuracy for Turkish License Plates. Mathematics and Computer Science, 6(6), 92-104. https://doi.org/10.11648/j.mcs.20210606.13

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    ACS Style

    Gulsum Cigdem Cavdaroglu; Mehmet Gokmen. A Character Segmentation Method to Increase Character Recognition Accuracy for Turkish License Plates. Math. Comput. Sci. 2021, 6(6), 92-104. doi: 10.11648/j.mcs.20210606.13

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    AMA Style

    Gulsum Cigdem Cavdaroglu, Mehmet Gokmen. A Character Segmentation Method to Increase Character Recognition Accuracy for Turkish License Plates. Math Comput Sci. 2021;6(6):92-104. doi: 10.11648/j.mcs.20210606.13

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  • @article{10.11648/j.mcs.20210606.13,
      author = {Gulsum Cigdem Cavdaroglu and Mehmet Gokmen},
      title = {A Character Segmentation Method to Increase Character Recognition Accuracy for Turkish License Plates},
      journal = {Mathematics and Computer Science},
      volume = {6},
      number = {6},
      pages = {92-104},
      doi = {10.11648/j.mcs.20210606.13},
      url = {https://doi.org/10.11648/j.mcs.20210606.13},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.mcs.20210606.13},
      abstract = {Automatic License Plate Recognition is a computer vision technology that provides a way to recognize the vehicle's license plates without direct human intervention. Developing Automatic License Plate Recognition methodologies is a widely studied topic among the computer vision community to increase the accuracy rates. Automatic License Plate Recognition systems include image acquisition and character segmentation phases. Although there are many studies, the research in character segmentation and improving recognition accuracy remains limited. The lack of an international standard for license plates and the misinterpretation of ambiguous characters are challenging problems for Automatic License Plate Recognition systems. Several academic works have shown that the ambiguous character problem can be overcome by using a second model that contains only these characters. In this study, we propose a new methodology to reduce the character recognition errors of Automatic License Plate Recognition systems. One of the reasons for the low accuracy rates is the problem of ambiguous characters. In most studies using OCR, it was observed that a single model was used for alphanumeric characters during the recognition phase. Instead of using a single model, using separate models for letters and digits will improve the recognition process and increase accuracy. Therefore, we determined whether the characters are letters or numbers, and we expressed the license plates in the form of letters - digits. The method suggested for segmenting blobs worked with an accuracy of 96.12% on the test dataset. The method recommended for generating letter-digit expressions for the license plates worked with an accuracy of 99.28% on the test dataset. The proposed methodology can work only on Turkish license plates. In future studies, we will expand our method by using the license plate dataset of a different country.},
     year = {2021}
    }
    

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  • TY  - JOUR
    T1  - A Character Segmentation Method to Increase Character Recognition Accuracy for Turkish License Plates
    AU  - Gulsum Cigdem Cavdaroglu
    AU  - Mehmet Gokmen
    Y1  - 2021/12/31
    PY  - 2021
    N1  - https://doi.org/10.11648/j.mcs.20210606.13
    DO  - 10.11648/j.mcs.20210606.13
    T2  - Mathematics and Computer Science
    JF  - Mathematics and Computer Science
    JO  - Mathematics and Computer Science
    SP  - 92
    EP  - 104
    PB  - Science Publishing Group
    SN  - 2575-6028
    UR  - https://doi.org/10.11648/j.mcs.20210606.13
    AB  - Automatic License Plate Recognition is a computer vision technology that provides a way to recognize the vehicle's license plates without direct human intervention. Developing Automatic License Plate Recognition methodologies is a widely studied topic among the computer vision community to increase the accuracy rates. Automatic License Plate Recognition systems include image acquisition and character segmentation phases. Although there are many studies, the research in character segmentation and improving recognition accuracy remains limited. The lack of an international standard for license plates and the misinterpretation of ambiguous characters are challenging problems for Automatic License Plate Recognition systems. Several academic works have shown that the ambiguous character problem can be overcome by using a second model that contains only these characters. In this study, we propose a new methodology to reduce the character recognition errors of Automatic License Plate Recognition systems. One of the reasons for the low accuracy rates is the problem of ambiguous characters. In most studies using OCR, it was observed that a single model was used for alphanumeric characters during the recognition phase. Instead of using a single model, using separate models for letters and digits will improve the recognition process and increase accuracy. Therefore, we determined whether the characters are letters or numbers, and we expressed the license plates in the form of letters - digits. The method suggested for segmenting blobs worked with an accuracy of 96.12% on the test dataset. The method recommended for generating letter-digit expressions for the license plates worked with an accuracy of 99.28% on the test dataset. The proposed methodology can work only on Turkish license plates. In future studies, we will expand our method by using the license plate dataset of a different country.
    VL  - 6
    IS  - 6
    ER  - 

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Author Information
  • Department of Information Technologies, Faculty of Economics, Administrative and Social Sciences, Isik University, Istanbul, Turkey

  • Altamira Digital Ventures, Istanbul, Turkey

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