A Survey of Elastic Matching Techniques for Handwritten Character Recognition

Seiichi UCHIDA  Hiroaki SAKOE  

IEICE TRANSACTIONS on Information and Systems   Vol.E88-D   No.8   pp.1781-1790
Publication Date: 2005/08/01
Online ISSN: 
DOI: 10.1093/ietisy/e88-d.8.1781
Print ISSN: 0916-8532
Type of Manuscript: SURVEY PAPER (Special Section on Document Image Understanding and Digital Documents)
Category: Character Recognition
elastic matching,  handwritten character recognition,  deformation,  optimization,  survey,  

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This paper presents a survey of elastic matching (EM) techniques employed in handwritten character recognition. EM is often called deformable template, flexible matching, or nonlinear template matching, and defined as the optimization problem of two-dimensional warping (2DW) which specifies the pixel-to-pixel correspondence between two subjected character image patterns. The pattern distance evaluated under optimized 2DW is invariant to a certain range of geometric deformations. Thus, by using the EM distance as a discriminant function, recognition systems robust to the deformations of handwritten characters can be realized. In this paper, EM techniques are classified according to the type of 2DW and the properties of each class are outlined. Several topics around EM, such as the category-dependent deformation tendency of handwritten characters, are also discussed.