Character segmentation for license plate recognition by K-means algorithm

Lihong Zheng, Xiangjian He

Research output: Chapter in Book/Conference proceedingConference contributionpeer-review

3 Citations (Scopus)


In this paper an improved K-means algorithm is presented to cut character out of the license plate images. Although there are many existing commercial LPR systems, with poor illumination conditions and moving vehicle the accuracy impaired. After examination and comparison of different image segmentation approaches, the K-means algorithm based method gave better image segmentation results. The K-means algorithm was modified by introducing automatic cluster number determination by filtering SIFT key points. After modification it efficiently detects the local maxima that represent different clusters in the image. The process is successful by getting a clean license plate image. While testing by the OCR software, the experimental results show a high accuracy of image segmentation and significantly higher recognition rate. The recognition rate increased from about 86.6% before our proposed process to about 94.03% after all unwanted non-character areas are removed. Hence, the overall recognition accuracy of LPR was improved.

Original languageEnglish
Title of host publicationImage Analysis and Processing, ICIAP 2011 - 16th International Conference, Proceedings
Number of pages10
EditionPART 2
Publication statusPublished - 2011
Externally publishedYes
Event16th International Conference on Image Analysis and Processing, ICIAP 2011 - Ravenna, Italy
Duration: 14 Sept 201116 Sept 2011

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
NumberPART 2
Volume6979 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference16th International Conference on Image Analysis and Processing, ICIAP 2011


  • K-means algorithm
  • LPR
  • image segmentation

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


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