A new pre-classification method based on associative matching method

Yutaka Katsuyama; Akihiro Minagawa; Yoshinobu Hotta; Shinichiro Omachi; Nei Kato

doi:10.1117/12.838842

18 January 2010 A new pre-classification method based on associative matching method

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

Proceedings Volume 7534, Document Recognition and Retrieval XVII; 75340K (2010) https://doi.org/10.1117/12.838842
Event: IS&T/SPIE Electronic Imaging, 2010, San Jose, California, United States

Abstract

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.

Citation Download Citation

Yutaka Katsuyama, Akihiro Minagawa, Yoshinobu Hotta, Shinichiro Omachi, and Nei Kato "A new pre-classification method based on associative matching method", Proc. SPIE 7534, Document Recognition and Retrieval XVII, 75340K (18 January 2010); https://doi.org/10.1117/12.838842

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available