End Notes - 2

Run over Barney.
The figures and materials on color histogramming used in this chapter were part
of research work conducted by Dale Hawkins in persistence of belief. His use of a
stuffed Barney doll started out from a class project: program a mobile robot to find a
Barney doll and run over it. This is actually a straightforward reactive project. The
Barney doll is a distinctive purple,making it easy for the vision systemto find it. The
project allowed the programmers to use the flat earth assumption, so trigonometry
could be used to estimate the location to the doll based on the location in image coordinates.
Hawkins’ program was the clear winner, running completely over Barney. It
also gave him vision code that he could reuse for his thesis.
Reactive soccer.
Color regions are often used to simplify tracking balls (and other robots) in robot
soccer competitions such as RoboCup and MIROSOT. One amusing aspect is that
many of these behaviors are purely reflexive; if the robot sees the ball, it responds,
but if it loses the ball, it stops. Ann Brigante and Dale Hawkins programmed a No

mad 200 to reflexively track a soccer ball to compare what would happen if the robot
had some concept of object permanence. Because of the angle of the camera, the robot
would lose sight of the ball when it was almost touching it. The behaviors that
emerged worked, but always generated much laughter. The robot would see the ball
and accelerate rapidly to its estimated location to “kick” it. When it got to the ball, it
suddenly deccelerated but had enough momentum to bump the ball. The ball would
slowly roll forward, back into the now-stationary robot’s field of view. The robot
would again jump forward, and the cycle would repeat endlessly.
Photographs and scanning.
Dale Hawkins, Mark Micire, Brian Minten, Mark Powell, and Jake Sprouse helped
photograph robots, sensors, and demonstrations of perceptual behaviors.