Brad Hayes

ObjectiveLab Hockey Rules2007 Season Highlight ReelChallengesShortcomingsResultsAlgorithmsDemo

Create a goaltending application to supplement the thrilling sport of Lab Hockey

Utilize computer vision techniques to add intelligence, and hence challenge, to the game

Come up with an innovative application for my thesis

Don’t break the iMacs. They’re brand new. Timeout means stop.

The player calling timeout forfeits the puck (ball) and switches to defense

Excessive timeouts by the defense will result in an automatic loss.

Players are either on offense or defense. Offense

Must shoot ball past the goaltender to score Scoring a goal causes a stoppage of play and offense is put

on defense. Defense

Cannot score points Must get puck (ball) between two designated objects

(typically trash cans) to switch to offense Involves a brief stoppage of play: Offense must retreat to mid-field

line.

Object tracking is hardEspecially fast moving, small objects like tennis

ballsWithout any information on the background,

object isolation can be expensiveBuilding a touch-screen is hard

Takes lots of time and patienceRelatively expensive

Not easy to say “Hey, lets shoot tennis balls at it. That seems like a good idea.”

If you want it to look decent, expect to burn yourself with the soldering iron at least once.In 10 years, I’ll tell people I got the scar while

fighting bears

No power tools? No problem.Materials will not be cut to exact specifications.

The frame probably looked about square until you read this bullet point.

All webcams are not created equalThe iSight is a fantastic webcam… running under OS X.The iSight is a fantastic nightmare running under VistaThe Lifecam VX-6000 is a fantastic webcam… running

under VistaThe Lifecam VX-6000 is a paperweight running under

OS X IR Filters are not made to be accessible

I’ve removed two of them.By removed, I mean shattered them.

Placing the camera in front of the screen to track the tennis ball is dangerousThe best vantage point to view the field is also

the worst if you value your equipmentPlacing the camera behind the screen to

catch IR blobs is problematicGlare from the projector bulbScreen is viewed at a bad angle

Homography can fix most of thisCannot pick up the tennis ball impact

IR Camera cannot pick up the tennis ball when it strikes the acrylic surface. Ideas that have failed:

Plain tennis ballTennis ball dotted with electrical tapeTennis ball covered with electrical tape, sticky-side outIR-enhanced hockey stick + sonic response

Taping an infrared-modified flashlight onto the end of the stick

Have the screen read the direction of the blade on impact.Place second camera watching screen, measure position on

impact Ideas that have not been tried yet:

550nm laser placed on the end of the bladeSame sonic response idea

Screen is still temperamentalDoes not auto-calibrate“Manual” calibration isn’t terribly effective

But is passable

OS X: LeopardBroke GIMP

Even the Leopard-specific versionBroke OpenCV

Input handling? Why would we need that to work?

Step 1) Finish Multimedia Project early, concentrate on other finals

Step 2) Realize that your webcam for the touch aspect of the screen isn’t going to work

Step 3) Run out to Best Buy at 10:00pmStep 4) Get a Windows-only webcam and realize

you have to recode everything for WindowsStep 5) Realize that the iSight you depended on

won’t play nicely with WindowsStep 6) Scour the internet for IEEE1394 Camera

Drivers(Side note: Monster Energy Drink is scary)

MajorObject Tracking Works

The goalie follows the ball, and is even somewhat decent at blocking shots

Multi-touch worksThe touch algorithm is fast enough to let the camera

work at a passable framerateExtensible Multi-touch Framework

Gesture recognition support forthcomingMinor

Fast pixel-level collision detection implemented Image TransparencySimple multi-touch drawing application to prove

functionality

Object TrackingTexture SamplingBackground EliminationHistogram CreationConstricting Window Algorithm

Touch detectionBlob DetectionGesture Recognition

Detect location of impact accuratelyIncrease framerate of multi-touch webcamIntegrate goalie controls with Wii Remote to

add another element to the gameConstruct housing for ball-tracking camera to

avoid damage