An Optimization Algorithm for Fractal Encoding of Graytone 2D Images

In this paper we describe an algorithm to find an Iterated Function System with associated probabilities (IFS) in order to generate a given coloured image. The proposed optimization algorithm, based on the Gradient method combined with Simulated Annealing, is much faster than the Simulated Annealing optimization algorithm on its own. Actually, more than one order of magnitude improvement in computational time has been gained. The overall algorithm can be viewed as a Simulated Quenching (SQ) method, which is quite efficient for the problem under consideration. Convergence results are reported and discussed and an example of coded image is included.