1. Aristotle University of Thessaloniki,Department of Informatics,Thessaloniki,Greece
2. University of Messina,Department of Mathematical and Computer Science, Physics and Hearth Sciences,Messina,Italy
3. Robotics, Vision and Control Group, University of Seville,Seville,Spain
4. Institute of Communications and Navigation, German Aerospace Center (DLR),Wessling,Germany
5. Engineering Ingegneria Informatica S.p.A,Research and Development Lab.,Rome,Italy