Printed Chinese character similarity measurement using ring projection and distance transform

Pong Chi YUEN*, G. C. Feng, Y. Y. Tang

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

20 Citations (Scopus)


This paper presents a new Chinese character similarity measurement method based on the ring projection algorithm and distance transform. The ring projection algorithm is used to transform a character image with two independent variables into a function of one independent variable in the ring projection space. This representation of character in the ring projection space has been proved to be in orientation and scale invariant. However, this representation will be distorted nonlinearly in the presence of noise. Therefore, common linear metrics such as Euclidean distance, cannot be applied to measure distance. To solve the nonlinear distortion problem, distance transform is proposed as a nonlinear metric. The similarity measurement is performed using the distance transformed image in the ring projection space. A number of Chinese characters are selected to evaluate the capability of the proposed measurement scheme and the results are encouraging.

Original languageEnglish
Pages (from-to)209-220
Number of pages12
JournalInternational Journal of Pattern Recognition and Artificial Intelligence
Issue number2
Publication statusPublished - Mar 1998

Scopus Subject Areas

  • Software
  • Computer Vision and Pattern Recognition
  • Artificial Intelligence

User-Defined Keywords

  • Chinese character recognition
  • Distance transform
  • Nonlinear distortion
  • Ring projection
  • Similarity measurement


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