A New Omnidirectional Vision Sensor for the Spatial Semantic Hierarchy E. Menegatti, M. Wright, E. Pagello Dep. of Electronics and Informatics University of Padua ITALY

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Introduction Robot’s task: Building a topological map of an unknown environment; Building a topological map of an unknown environment;Sensor: Omnidirectional vision system; Work’s aim: Prove effectiveness of omnidirectional sensors for Spatial Semantic Hierarchy;

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Spatial Semantic Hierarchy A model of the human knowledge of large spaces Layers: –Sensory Level –Control Level –Causal Level –Topological Level –Metrical Level Interface with the robot’s sensory system Control Laws, Transition of State, Distinctiveness Measure View, Action, Distinct Place Abstracts Discrete from Continous Minimal set of Places, Paths and Regions Distance, Direction, Shape Useful, but seldom essential

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Omnidirectional Camera Composed of: n Standard Colour Camera n Convex Mirror n Perspex Cylinder

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Pros e Cons Advantages n Wide vision field n High speed n Vertical Lines n Rotational Invariance Disadvantages n Low Resolution n Distortions n Low readability

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Omnidir. Vision and SSH n View Omnidirectional image n Discriminate b/t “turns” and “travels” n Effective Distinctiveness measure P2 P4P3 P5P1 –Exploring around the block

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Assumptions n Man-made environment n Floor flat and horizontal n Wall and objects surfaces are vertical n Static objects n Constant Lighting n Robot translates or rotates n No encoders

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Features and Events Feature: –Vertical Edges Events: –A new edge –An edge disappear –Two edges 180° apart –Two pairs of edges 180° apart

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Experiments Tasks of Caboto: n Navigation; n Map building; Techniques: n Edge detection; n Colour marking;

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Caboto’s Images

E. Menegatti - A New Omnidirectional Vision Sensor for SSH

Results n Correct tracking of edges n Recognization of actions n Calculation of the turn angle The path segmentation

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Mirror Design n Design custom mirror profile n Maximise resolution in ROIs Mirror Profile Mirror shape should depend on robot task!

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Our new mirror

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Conclusion n Omnidirectional vision sensor is a good sensor for map building with SSH n Egomotion of the robot was estimated without active vision n The use of a mirror designed for this application will improve the system

E. Menegatti - A New Omnidirectional Vision Sensor for SSH Omnidirectional Cameras n Compound-eye camera (from (from Univ. of Maryland, College Park. ) n Panoramic cameras (from Apple) n Omnidirectional cameras (from (from University of Picardie - France)