Development of a Robust and Compact On-Line Handwritten Japanese Text Recognizer for Hand-Held Devices

Jinfeng GAO  Bilan ZHU  Masaki NAKAGAWA  

IEICE TRANSACTIONS on Information and Systems   Vol.E96-D   No.4   pp.927-938
Publication Date: 2013/04/01
Online ISSN: 1745-1361
DOI: 10.1587/transinf.E96.D.927
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Pattern Recognition
on-line recognition,  handwritten text recognition,  elastic matching,  MQDF,  vector quantization,  

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The paper describes how a robust and compact on-line handwritten Japanese text recognizer was developed by compressing each component of an integrated text recognition system including a SVM classifier to evaluate segmentation points, an on-line and off-line combined character recognizer, a linguistic context processor, and a geometric context evaluation module to deploy it on hand-held devices. Selecting an elastic-matching based on-line recognizer and compressing MQDF2 via a combination of LDA, vector quantization and data type transformation, have contributed to building a remarkably small yet robust recognizer. The compact text recognizer covering 7,097 character classes just requires about 15 MB memory to keep 93.11% accuracy on horizontal text lines extracted from the TUAT Kondate database. Compared with the original full-scale Japanese text recognizer, the memory size is reduced from 64.1 MB to 14.9 MB while the accuracy loss is only 0.5% from 93.6% to 93.11%. The method is scalable so even systems of less than 11 MB or less than 6 MB still remain 92.80% or 90.02% accuracy, respectively.