Ranking of Optical Character Prototypes in a Large Database Using Isothetic Chord Lengths

A novel algorithm for conferring a ranking system on the prototypes of a large database of optical/handwritten characters is proposed. The ranking system is designed using the (isothetic) chord lengths of the enclosing isothetic polygons corresponding to the prototypes, for a prescribed grid-size. As the derivation of structural information of a character by thinning or by edge detection is susceptible to its impurity during imaging or post-processing, an isothetic polygon is used that captures the geometric structure of the character in an elegant way. The proposed scheme has a striking potential in deciding the relative merit and usefulness of a particular prototype with respect to the other prototypes of the corresponding character in the concerned database. Several quantitative measures have been suggested, and supporting experimental results have been reported, which justify the strength and efficiency of the proposed method