General Central Projection Systems

Acknowledgements The first acknowledgement goes to my advisor Prof. Helder Araujo. He was the one who introduced me to computer vision research and helped on my first steps on the field. During these remarkable six years we worked and argued a lot. It was an enjoyable experience even in the bad moments when things were not going so well. This experience would never be possible without his help and advise. Thank you very much for these six years and I hope that we can continue working together in the future. I also thank the Institute of Systems and Robotics and its president Prof. Traca de Almeida. The ISR has been the institution where I've developed the majority of my research and that mainly supported my expenses and travels to conferences. I also have to acknowledge the Department of Electrical and Computer Engineering as well as the PRODEP program. I would like to mention in particular the Head of the Department, Prof. Luis Sa, for his trust and support to the plan of getting a PRODEP grant. During these years I've collected a huge list of colleagues that in the meanwhile become my personal friends. The " seniors " Jorge Batista and Paulo Peixoto. Paulo Menezes, who was my advisor during the undergraduate studies (people never forget the first one). And all the others that I met during these years: Johnny and Hugo (my emergency technical advisers) The Calouste de Gulbenkian Foundation has partially supported my stay in France in 2002. In France I've to acknowledge the INRIA Rhone-Alpes and the Head of group MOVI, Prof. Radu Horaud, who received me. I also would like to thank all the terrific people that I met. In particular Cristi (my personal optimization teacher), Navneet (my ski mate), Peter and Edmond. In the United States I thank the GRASP Lab., at the University of Pennsylva-nia, and Prof. Kostas Daniilidis which made this experience possible. In a personal level I think that the people that I would like to mention would not fit in this page. Thus I will only say to my family and friends ... thank you very much! v vi Contents Acknowledgements v 1 Introduction 1 1.