Motion Tracking with theRCX and Quickcam

Dan HuberJoe Winegarden

http://www4.ncsu.edu/~jjwinega/csc714/CSC 714 Final Project

Motion Tracking Setup Quickcam mounted on top

of motor, RCX brick sits to the side for less weight

Quickcam connected to linux PC via USB

PC runs lnpd to communicate with IR tower

PC runs frame grabber code, sends messages through tower to RCX

RCX waits for message received, rotates until told to do otherwise

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PC Workstation

LEGO USB QuickCamLEGO RCX Brick

Image Data

Output Actuators

Control Information

Image Processing Grab frames every 50

ms, determine where “most blue” pixel is located based on center of frame

Messages are 0 (stop turning), 1 (rotate left), 2 (rotate right)

Issues Solved/Unsolved Improv image processing software difficult to adapt to

our application, so we wrote all frame-grabbing and image processing code ourselves Video4Linux API for frame-grabbing code

lnpd makes IR communication very simple: Completely separate from BrickOS Just include library and call 'lnp_addressing_write()'

Extremely stiff USB camera cable greatly restricts the rotational movement of the camera Can't follow blue pen more than a few degrees without

requiring man-power to assist camera movement

Reacts in real time!