Patrice Abry is a professor in the Laboratoire de Physique at the Ecole Normale Superieure in Lyon, France. Paulo Goncalves is an associate researcher at INRIA, both with Fractales and with a research team at INRIA Rhone-Alpes. Jacques Levy Vehel is currently a research director at INRIA, Rocquencourt, where he created the Fractales team, a research group devoted to the study of fractal analysis and its applications to signal/image processing.