Previously a VEXplorer robot was modified for computer control. Basically the remote was hacked and a microprocessor provides a serial to PPM interface. Details are here. Once the VEXplorer could be treated as a serial device, the camera could act as a sensor. A program was written in RoboRealm to control the robots behavior based on image data. Basically there are four components to the program. First there is programmatic motion to get it close to the desired object. Then a sorbel filter is applied to pick out a line in electric tape. The robot navigates to the line. At this point the robot begins looking for a red object and approaches the object until its geometry matches the top of the can. At this point the gripper is engaged and the robot reverses its path to its original position.
Here is the .robo file for use in Roborealm
Here is a video of the robot navigating.