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A New Omnidirectional A New Omnidirectional Vision Sensor for the Vision Sensor for the
Spatial Semantic Spatial Semantic HierarchyHierarchy
EE.. Menegatti Menegatti, M. Wright, E. , M. Wright, E. PagelloPagello
Dep. of Electronics Dep. of Electronics and Informaticsand Informatics
University of PaduUniversity of Padua a ITALYITALY
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
IntroductionIntroduction
Robot’s task: Robot’s task: Building a topological map of an Building a topological map of an
unknown environment;unknown environment;
Sensor:Sensor:Omnidirectional vision system;Omnidirectional vision system;
Work’s aim:Work’s aim:Prove effectiveness of omnidirectional Prove effectiveness of omnidirectional
sensors for Spatial Semantic Hierarchy;sensors for Spatial Semantic Hierarchy;
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
Spatial Semantic Spatial Semantic Hierarchy...Hierarchy...
... A model of the human knowledge ... A model of the human knowledge of large spacesof large spaces
Layers:Layers:
–Sensory LevelSensory Level
–Control LevelControl Level
–Causal LevelCausal Level
–Topological LevelTopological Level
–Metrical LevelMetrical Level
Interface with the robot’s Interface with the robot’s sensory systemsensory system
Control Laws, Transition of Control Laws, Transition of State, Distinctiveness State, Distinctiveness
MeasureMeasure
View, Action, Distinct PlaceView, Action, Distinct Place
Abstracts Discrete from Abstracts Discrete from ContinousContinous
Minimal set ofMinimal set ofPlaces, Paths and RegionsPlaces, Paths and Regions
Distance, Direction, ShapeDistance, Direction, Shape
Useful, but seldom Useful, but seldom essentialessential
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
Omnidirectional CameraOmnidirectional Camera
Composed of:Composed of: Standard Colour Standard Colour
Camera Camera Convex MirrorConvex Mirror Perspex CylinderPerspex Cylinder
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
Pros e ConsPros e Cons
AdvantagesAdvantages
Wide vision fieldWide vision field
High speedHigh speed Vertical LinesVertical Lines Rotational Rotational
InvarianceInvariance
DisadvantagesDisadvantages
Low ResolutionLow Resolution
DistortionsDistortions
Low readabilityLow readability
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
Omnidir. Vision and SSHOmnidir. Vision and SSH View Omnidirectional imageView Omnidirectional image
Discriminate b/t “Discriminate b/t “turns”turns” and “ and “travels”travels” Effective Distinctiveness measureEffective Distinctiveness measure
P2P2
P4P4 P3P3
P5P5
P1P1
–Exploring around the blockExploring around the block
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
AssumptionsAssumptions
Man-made environmentMan-made environment
Floor flat and horizontalFloor flat and horizontal
Wall and objects surfaces are verticalWall and objects surfaces are vertical
Static objectsStatic objects
Constant LightingConstant Lighting
Robot translates or rotatesRobot translates or rotates
No encodersNo encoders
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
Features and EventsFeatures and Events
Feature:Feature:– Vertical EdgesVertical Edges
Events:Events:– A new edgeA new edge– An edge disappearAn edge disappear– Two edges 180° apartTwo edges 180° apart– Two pairs of edges 180° Two pairs of edges 180°
apartapart
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
ExperimentsExperiments
Tasks of Caboto:Tasks of Caboto: Navigation;Navigation; Map building;Map building;
Techniques:Techniques: Edge detection;Edge detection; Colour marking;Colour marking;
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
Caboto’s ImagesCaboto’s Images
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
ResultsResults Correct tracking of edgesCorrect tracking of edges ReReccogniognization zation of of actionsactions Calculation of the turn angleCalculation of the turn angle
The path The path segmentationsegmentation
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
Mirror DesignMirror Design
Design Design customcustom mirror profilemirror profile
Maximise resolution Maximise resolution
in ROIsin ROIs
Mirror ProfileMirror Profile
Mirror shape should depend on robotMirror shape should depend on robot task!task!
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
Our new mirrorOur new mirror
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
ConclusionConclusion
Omnidirectional vision sensor is a Omnidirectional vision sensor is a good sensor for map building with good sensor for map building with SSHSSH
Egomotion of the robot was Egomotion of the robot was estimated without active visionestimated without active vision
The use of a mirror designed for this The use of a mirror designed for this application will improve the systemapplication will improve the system
E. Menegatti - A New Omnidirectional Vision Sensor for SSH
Omnidirectional CamerasOmnidirectional Cameras Compound-eye Compound-eye
camera camera (from (from Univ. of Maryland, College
Park. )
Panoramic cameras Panoramic cameras (from Apple)(from Apple)
Omnidirectional Omnidirectional camerascameras
(from (from University of Picardie - France)