Journal of the Institute of Convergence Signal Processing (융합신호처리학회논문지)

The Korea Institute of Convergence Signal Processing (한국융합신호처리학회)
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Vehicle Number Plate Detection using Corner Information

꼭짓점 정보를 이용한 자동차 번호판 검출

  • 김진욱 (경상대학교 제어계측공학과 비전연구설) ;
  • 박중조 (경상대학교 제어계측공학과, ERI)
  • Received : 2012.09.02
  • Accepted : 2012.11.03
  • Published : 2012.10.30
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Abstract

In this paper, we presents a new method for vehicle number plate detection. Our method is basically the method extracting a rectangles from a car image because the shape of a vehicle number plate is a rectangle. For detecting the vehicle number plate, firstly, the contrast of the input image is enhanced. Then, the lines in the image are obtained by using LSD(line segment detector), and rectangles in the image are detected from the line data. These rectangles are the candidates of the car plate, from which the car plate is selected. In this procedure, the method of detecting rectangles is our proposed method, which consists of three stages: (1) extracting corners from the line segments by LSD; (2) extracting diagonal lines from the corner data; and (3) detecting rectangles from diagonal line information. And finally the vehicle number plate is selected from these rectangles by using the feature of the vehicle number plate and the inside information of rectangles. In the experiments with the 100 images captured by our digital camera, we have achieved a detection rate of 94%.

본 논문에서는 자동차 번호판을 검출하는 새로운 방법을 제시한다. 자동차 번호판은 사각형 모양이므로 우리의 방법은 기본적으로 입력 영상에서 사각형을 추출하는 방법이 된다. 번호판을 검출하기 위해, 먼저 입력영상의 콘트라스트를 향상시키고, 그 후 LSD(Line segment detector) 기법을 사용하여 영상내의 선을 검출하고, 이 선 정보로 부터 사각형들을 추출 한다. 이 사각형들은 번호판 후보들이 되고, 이로부터 번호판이 검출된다. 이중에서 본 연구가 제안하는 부분은 사각형 추출방법으로서, 이 방법은 3단계로 구성된다: (1) 먼저, LSD에 의해 얻어진 선으로부터 꼭짓점들을 추출한다; (2) 구해진 꼭짓점들을 사용하여 사각형의 대각선을 검출한다; (3) 그 후, 대각선 정보를 이용하여 사각형을 추출해 낸다. 최종적으로 번호판 특성과 사각형 내부 정보를 이용하여 이 사각형들로부터 번호판이 선택된다. 100장의 자동차 영상을 촬영하여 실험한 결과 94%의 검출율을 달성하였다.

Keywords

References

  1. E. R. Lee, P. K. Kim and H. J. Kim. "Automatic Recognition of a Car License Plate Using CoIor Image Processing", Proceeding of IEEE International Conference on Image Processing (ICIP'94), VOL.2, pp. 301-305, 1994.
  2. Thanongsak Sirithinaphong and Kosin Chamnongthai "The Recognition of Car License Plate for Automatic Parking System", Processing of the Fifth International Symposium on Signal Processing and Its Applications (lSSPA '99), pp. 455-457, 1999.
  3. Jian-Feng Xu, Shao-Fa Li and Mian- Shui Yu, "Car License Plate Extraction using CoIor and Edge Information", Proceedings of the Third International Conference on Machine Learmng and Cybemetics, pp.3904-3907, Shanghai, 26-29 August 2004
  4. W. Jia, H. Zhang, X. He and M. Piccardi, "Mean Shift for Accurate License Plate Localization", Proceedings of International Conference on Intelligent Transportation Systems, Vienna, Austria, pp.566-571, 2005.
  5. Kaushik Deb, Hyun-Uk Chae and Kang-Hyun Jo, "Vehicle License Plate Detection Method Based on Sliding Concentric Windows and Histogram", Journal of Computers, Vol. 4, No. 8, pp. 771-777. August 2009
  6. S. H. Park, K. I. Kim, K. Jung and H. J. Kim, "Locating Car License Plates using Neural Network", IEE Electronics Letters, vol.35, no. 17, pp. 1475-1477, 1999. https://doi.org/10.1049/el:19990977
  7. J. Matas and K. Zimmermann, "Unconstrained Licence Plate and Text Localization and Recognition", Proceedings of 2005 IEEE Intelligent Transportation Systems, pp. 225-230, 2005.
  8. S. H. Kim, D. C. Kim, Y. B. Ryu and G. H. Kim. "A Robust License plate Extraction Method under Complex Image Conditions", Proceedings of 16th International Conference on Pattern Recognition, pp. 216-219 vol.3, 2002.
  9. P. V. Suryanarayana, Suman K. Mitra and Asim Baneree and Anil K. Roy, "A Morphology Based Approach for Car License Plate Extraction", IEEE lndicon 2005 Conference, pp.24-27, India, 2005.
  10. Serkan Ozbay, and Ergun Ercelebi, "Automatic Vehicle Identification by Plate Recognition", World Academy of Science, Engineering and Technology 9, pp,222-225, 2005.
  11. Vahid Abolghasemi and Alireza Ahmadyfard, "Local Enhancement of Car Image for License Plate Detection", 15th European Signal Processing Conference (EUSIPCO 2007), Poznan, Poland, pp.2179-2183, September 3-7, 2007
  12. Chirag N. Paunwala, Suprava, and Manoj Chaudhary, "Multiple License Plate Extraction Based on Mathematical Morphology and Component Filtering in Indian Traffic Condition". 2010 International Conference on Advances in Recent Technologies in Communication and Computing, pp.249-242. 2010.
  13. A. Beghdadi and A. Le Negrate, "Contrast enhancement technique based on local detection of edges", Computer Vision, Graphics, and Image Processing, Vol. 46, pp. 162-174, 1989. https://doi.org/10.1016/0734-189X(89)90166-7
  14. R. Grompone von Gioi, J. Jakubowicz, J.M. Morel, and G. Randall, "LSD: A Fast Line Segment Detector with a False Detection Control", IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol. 32, No. 4, pp. 722-732, April 2010. https://doi.org/10.1109/TPAMI.2008.300
  15. Yasuharu Yabanyra, Masahiro Goto, Diasuke Nishiyama. "Extraction and Tracking of the License Plate Using Hough Transform and Voted Block Matching", IEEE Intelligent Vehicles Symposium Conference, pp. 243-246, 2003.
  16. Claudio Rosito Jung and Rodrigo Schramm, "Rectangle Detection based on a Windowed Hough Transform", Proceedings of Computer Graphics and Image Processing. 17th Brazilian Symposium, pp. 113-120, Oct. 2004
  17. Zi-qiang Li, "Generalized Hough Transform: Fast Detection for Hybrid Multi-Circle and Multi-Rectangle", Intelligent Ccntrol and Automation, WCICA 2006, pp. 10130-10134. 2006
  18. R. C. Gonzalez and R. E. Woods, Digital image processing, Addison-Wesley, 1992.
  19. N. Otsu, "A Threshold Selection Method from Gray-Level Histogram", IEEE Transactions on System, Man, Cybernetics, Vol. SMC-9, No.1, pp 62-66, January 1979.