A Novel Approach to Skew Detection and Character Segmentation for Handwritten Bangla Words

Character segmentation is a necessary preprocessing step for character recognition in many handwritten word recognition systems. The most difficult case in character segmentation is the cursive script. Fully cursive nature of Bangla handwriting, the natural skewness in words poses some challenges for automatic character segmentation. In this article a novel approach to skew detection, correction as well as character segmentation has been presented for handwritten Bangla words as a test case. Segmenting points are extracted on the basis of some patterns observed in the handwritten words. With these segmenting points a graphical path (hereafter referred to as a candidate path) has been constructed. The handwritten words contain some consistent and also inconsistent skewness. Our algorithm can cope with both types of skewness at a time. Further the method is so direct that with the help of a candidate path one can handle both skew correction and segmentation successfully. the algorithm has been tested on a database prepared for laboratory use. The method yields fairly good results for this database.

1. Introduction

We consider here the task of automatic segmentation of handwriting for Bangla, the second-most popular language and script in the Indian subcontinent and the fifth-most popular language in the world. There are 50 basic characters (11 vowels and 39 consonants) in Bangla apart from the numerals. Obviously the structure of handwritten document is more complicated than the text document. Moreover the task considered here is much more difficult than segmentation of handwritten Roman script, as the Bangla scripts are very much cursive in nature. A number of handwritten samples covering a reasonably large spectrum of handwriting style have been collected form people of various levels of age, literacy and profession. A set of names of small, medium and large towns of West Bengal is the database concerned. The work has two main parts as- 1.

Skew detection and correction.

2.

Character segmentation.