Designing an omnidirectional vision system for a goalkeeper robot E. Menegatti, F. Nori, E. Pagello, C. Pellizzari, D. Spagnoli Dept. of Electronics and Informatics The University of Padua Italy

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Presentation’s Outline n The design of an omnidirectional mirror n How the task commits the design n Comparison b/t two mirrors designed for different tasks

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Related works Bonarini [1999]: –Conical mirror with spherical vertex Hicks [1999]: –Linear mirror –Numerically solves differential equation Sorrenti [2000]: –Multi-part mirror –Isometric mirror –Geometrically solves differential equation

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Mirror for a goalkeeper The task of the robot must determine the mirror profile the mirror profile The goalie’s tasks: –Self-localize –Locate the ball –Intercept the ball Requirements: –Good accuracy close to the robot –Large field of view

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Different Mirror Profiles ProfileProsCons Conical n No body n Const. Rel. Error n Close is small n Small FOV Conical with Spherical Vertex n Close is big n Const. Rel. Error n Body n Small FOV Isometric n Const. Abs. error n Preserve size n Body n Big Rel. Error

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot The mirror we designed... Three parts: n Measurement Mirror n Marker Mirror n Proximity Mirror Mirror Profile The task determines the mirror profile

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot How to design a mirror... Mirror profile construction Pin Hole Vertex Y X Pin Hole Vertex D Min D Max X Y d Max d1d1 D1D1 Pin Hole Vertex D Min D Max X Y d Max d1d1 D1D1 Pin Hole Vertex D Min D Max X Y d Max d1d1 D1D1 Pin Hole Vertex D Min D Max X Y d Max d1d1 D1D1 x y P Pin Hole Vertex D Min D Max X Y d Max d1d1 D1D1 Pin Hole Vertex D Min D Max X Y d Max d1d1 D1D1 Pin Hole Vertex D Min D Max X Y d Max d1d1 D1D1 Pin Hole Vertex D Min D Max X Y d Max d1d1 D1D1 Pin Hole Vertex D Min D Max X Y d Max d1d1 D1D1

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Simulations From the MatLab output to the PovRay Ray Tracer Model of the Mirror Simulated sequence

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Actual Mirror Picture of Lisa’s mirror Omnidirectional sequence

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Omnidirectional Software n Calculating Ball Position n Localisation using goalposts n Goalkeeper Behaviour

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Calculating Ball Position Proportion b/t measurement mirror and proximity mirror

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Localisation using goalposts Goalpost bottoms n Find goalpost azimuth and distance n Re-localisation is dangerous

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Goalkeeper Behaviour n Inactive ball n Shot in goal n Dangerous ball n New goalkeeper moving n Comparison with old moving BallPos(t+1)BallPos(t)

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot A Goalie's Mirror vs. An Attacker’s Mirror Goalkeeper Attacker

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Requirements For Goalie: n Locate the ball n Identify the markers n See the defended goal For Attacker: n Locate the ball n Identify the markers n See both goals n Lighter mirror

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot The attacker’s mirror Play on what you see, i.e. “No absolute localisation in decision making!” LighterLighter SmallerSmaller Wider FOVWider FOV The new mirror

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Two Mirrors, Two Tasks GoalkeeperAttacker

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Conclusion n We showed how the task commits the mirror design n We gave details on a mirror design procedure n We gave practical hints on goalkeeper behaviour n We highlighted the danger of a re-localisation process during a shot

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot Acknowledgments We wish to thank: n A. Bonarini and D. Sorrenti n The other members of the Artisti Veneti Team: M. Barbon, M. Bert, C. Moroni, S. Zaffalon. This research has been supported by: n The Parallel Computing Project of the Italian Energy Agency (ENEA) n The Special Project on Multi Robot Cooperative Systems of the University of Padua

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot The Heterogeneous Team