Connected Script Synthesis by Character Concatenation—A Bezier Curve Based Formulation

Abstract

In this paper, we address the problem of synthesizing connected handwritten script from individual characters written in isolation. Connected writing is viewed as a natural evolution from writing the characters in isolation, characterized by the use of continuous pen-down connecting movement from one character to the next. The problem is one of concatenation of individual character shapes to generate the connected script and consists in synthesizing a so called transition stroke from one character to the next. Particular emphasis is laid on recreating the context effect underlying the pen-down transition stroke and in preserving the continuity of motion and shape in the transition. Under this framework, we propose an approach based on a shape specific splining technique where the transition stroke is generated from the isolated character shapes by a direct application of the Bézier curve formulation, Here, in the concatenation of two characters, the end segments of the characters are considered as the control points and the resulting Bézier curve forms the required transition, satisfying first order continuity at the transition points. The appropriateness of the direct application of the Bézier curve formulation is shown through the important primary properties of Bézier curves with reference to the observed characteristics of a transition stroke in natural connected writing. The results obtained using this approach reveal its potential in closely modelling the context effects in natural connected handwriting and in synthesizing connected script with a convincingly high degree of naturalness.

Indexing terms:

• Connected script
• Character concatenation
• Transition strokes