Designing an Designing an omnidirectional vision omnidirectional vision

system for a goalkeeper system for a goalkeeper robotrobot

E. Menegatti, F. Nori, E. Pagello, E. Menegatti, F. Nori, E. Pagello, C. Pellizzari, D. SpagnoliC. Pellizzari, D. Spagnoli

Dept. of Dept. of Electronics and Electronics and

InformaticsInformaticsThe University of The University of

Padua ItalyPadua Italy

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

Presentation’s OutlinePresentation’s Outline The design of an omnidirectional The design of an omnidirectional

mirrormirror How the task commits the designHow the task commits the design Comparison b/t two mirrors Comparison b/t two mirrors

designed for different tasksdesigned for different tasks

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

Related worksRelated worksBonarini [1999]:Bonarini [1999]:

– Conical mirror with spherical vertexConical mirror with spherical vertexHicks [1999]:Hicks [1999]:

– Linear mirrorLinear mirror– Numerically solves differential Numerically solves differential

equationequationSorrenti [2000]:Sorrenti [2000]:

– Multi-part mirrorMulti-part mirror– Isometric mirrorIsometric mirror– Geometrically solves differential Geometrically solves differential

equationequation

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

Mirror for a goalkeeperMirror for a goalkeeperThe task of the robot must determineThe task of the robot must determine

the mirror profilethe mirror profile

The goalie’s The goalie’s tasks:tasks:

–Self-localizeSelf-localize–Locate the ballLocate the ball–Intercept the Intercept the ball ball

Requirements:Requirements:– Good accuracy Good accuracy

close to the close to the robotrobot

– Large field of Large field of viewview

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

Different Mirror ProfilesDifferent Mirror ProfilesProfileProfile ProsPros ConsConsConicalConical No bodyNo body

Const. Rel. ErrorConst. Rel. Error Close is smallClose is small Small FOVSmall FOV

Conical with Conical with Spherical Spherical VertexVertex

Close is bigClose is big Const. Rel. ErrorConst. Rel. Error

BodyBody Small FOVSmall FOV

IsometricIsometric Const. Abs. errorConst. Abs. error Preserve sizePreserve size

BodyBody Big Rel. Error Big Rel. Error

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

The mirror we designed...The mirror we designed...Three parts:Three parts: Measurement MirrorMeasurement Mirror Marker MirrorMarker Mirror Proximity MirrorProximity Mirror

Mirror ProfileMirror ProfileThe task The task determines the determines the mirror profilemirror profile

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

How to design a mirror...How to design a mirror...

Mirror profile constructionMirror profile construction

Pin Hole

Vertex

Y

X

Pin Hole

Vertex

DMin DMax

X

Y

dMax d1

D1

Pin Hole

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DMin DMax

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dMax d1

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DMin DMax

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dMax d1

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E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

SimulationsSimulationsFrom the MatLab output to the PovRay Ray TracerFrom the MatLab output to the PovRay Ray Tracer

Model of the MirrorModel of the Mirror Simulated sequenceSimulated sequence

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

Actual MirrorActual Mirror

Picture of Lisa’s mirrorPicture of Lisa’s mirror Omnidirectional sequenceOmnidirectional sequence

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

Omnidirectional SoftwareOmnidirectional Software Calculating Ball PositionCalculating Ball Position Localisation using Localisation using goalpostsgoalposts Goalkeeper BehaviourGoalkeeper Behaviour

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

Calculating Ball PositionCalculating Ball PositionProportion b/t measurement mirror and Proportion b/t measurement mirror and

proximity mirrorproximity mirror

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

Localisation using Localisation using goalpostsgoalposts

Goalpost bottoms

Find goalpost Find goalpost azimuth and azimuth and distancedistance

Re-localisation Re-localisation is dangerousis dangerous

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

Goalkeeper BehaviourGoalkeeper Behaviour

Inactive ballInactive ball Shot in goalShot in goal Dangerous ballDangerous ball

New goalkeeper movingNew goalkeeper moving Comparison with old movingComparison with old moving

BallPos(t+1)BallPos(t+1)

BallPos(t)BallPos(t)

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

A Goalie's Mirror vs. A Goalie's Mirror vs. An Attacker’s MirrorAn Attacker’s Mirror

GoalkeeperGoalkeeper AttackerAttacker

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

RequirementsRequirementsFor Goalie:For Goalie: Locate the ballLocate the ball Identify the Identify the

markersmarkers See the defended See the defended

goalgoal

For Attacker:For Attacker: Locate the ballLocate the ball Identify the Identify the

markersmarkers See both goalsSee both goals Lighter mirrorLighter mirror

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

The attacker’s mirrorThe attacker’s mirror

Play on what you see, i.e. Play on what you see, i.e. ““No absolute localisation in decision making!”No absolute localisation in decision making!”

• LighterLighter

• SmallerSmaller

• Wider FOVWider FOVThe new mirrorThe new mirror

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

Two Mirrors, Two TasksTwo Mirrors, Two Tasks

GoalkeeperGoalkeeper AttackerAttacker

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

ConclusionConclusion We showed how the task commits the We showed how the task commits the

mirror design mirror design We gave details on a mirror design We gave details on a mirror design

procedureprocedure We gave practical hints on goalkeeper We gave practical hints on goalkeeper

behaviourbehaviour We highlighted the danger of a re-We highlighted the danger of a re-

localisation process during a shotlocalisation process during a shot

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

AcknowledgmentsAcknowledgmentsWe wish to thankWe wish to thank:: A. Bonarini and D. SorrentiA. Bonarini and D. Sorrenti The other members of the The other members of the Artisti Veneti Artisti Veneti

TeamTeam:: M. Barbon, M. Bert, C. M. Barbon, M. Bert, C. Moroni, S. Zaffalon.Moroni, S. Zaffalon.

This research has been supported by: This research has been supported by: The Parallel Computing Project of the Italian The Parallel Computing Project of the Italian

Energy Agency (ENEA) Energy Agency (ENEA) The Special Project on Multi Robot Cooperative The Special Project on Multi Robot Cooperative

Systems of the University of PaduaSystems of the University of Padua

E. Menegatti et al. - Omnidirectional Vision for Goalkeeper Robot

The Heterogeneous TeamThe Heterogeneous Team