1. a Signal and Image Centre (SIC) – Royal Military Academy (RMA) , Av. de la Renaissance 30, 1000 Brussels, Belgium
2. b Institute of Intelligent Systems for Automation (ISSIA) – National Research Council (CNR) , Via G. Amendola 122/D‐I, 70126 Bari, Italy
3. c Biophysics Group , Dept. of Chemistry – Göteborg University , Medicinaregatan 9C, SE‐413 90 Göteborg, Sweden