A qualitative shape model for 2D semi-fractals

In this paper, a qualitative shape model for 2D semi-fractals is presented. First, based on iterated functions system (IFS) theory and formal language theory, a shape representation formalism called regular generation system (RGS) is proposed to qualitatively represent 2D semi-fractal shape. Then, based on an inductive automata learning algorithm, a modeling procedure for natural semi-fractals is described. Finally, examples are presented to demonstrate the representation mechanism and the modeling method of RGS. Since RGS combines and extends Prusinkiewicz's (1992) and Gujar's (1993) works on representing fractals and provides a modeling procedure, RGS is a complete and effective shape model for 2D semi-fractals.