A new pre-classification method based on associative matching method

Yutaka Katsuyama*, Akihiro Minagawa, Yoshinobu Hotta, Shinichiro Omachi, Nei Kato


研究成果: Conference contribution

1 被引用数 (Scopus)


Reducing the time complexity of character matching is critical to the development of efficient Japanese Optical Character Recognition (OCR) systems. To shorten processing time, recognition is usually split into separate preclassification and recognition stages. For high overall recognition performance, the pre-classification stage must both have very high classification accuracy and return only a small number of putative character categories for further processing. Furthermore, for any practical system, the speed of the pre-classification stage is also critical. The associative matching (AM) method has often been used for fast pre-classification, because its use of a hash table and reliance solely on logical bit operations to select categories makes it highly efficient. However, redundant certain level of redundancy exists in the hash table because it is constructed using only the minimum and maximum values of the data on each axis and therefore does not take account of the distribution of the data. We propose a modified associative matching method that satisfies the performance criteria described above but in a fraction of the time by modifying the hash table to reflect the underlying distribution of training characters. Furthermore, we show that our approach outperforms pre-classification by clustering, ANN and conventional AM in terms of classification accuracy, discriminative power and speed. Compared to conventional associative matching, the proposed approach results in a 47% reduction in total processing time across an evaluation test set comprising 116,528 Japanese character images.

ホスト出版物のタイトルProceedings of SPIE-IS and T Electronic Imaging - Document Recognition and Retrieval XVII
出版ステータスPublished - 2010
イベントDocument Recognition and Retrieval XVII - San Jose, CA, United States
継続期間: 2010 1月 192010 1月 21


名前Proceedings of SPIE - The International Society for Optical Engineering


ConferenceDocument Recognition and Retrieval XVII
国/地域United States
CitySan Jose, CA

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学
  • コンピュータ サイエンスの応用
  • 応用数学
  • 電子工学および電気工学


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