1. Swedish Transport Administration, Department of Investment , Box 366/ Neptunigatan 52 , SE-201 23 Malmö , Sweden
2. Université Libre de Bruxelles (ULB), École polytechnique de Bruxelles (Brussels Faculty of Engineering), Laboratory of Image Synthesis and Analysis (LISA). Campus de Solbosch, ULB – LISA CP165/57, Av. F. D. Roosevelt 50 , B-1050 Brussels , Belgium