Tracking movement of balloons

For my final Master project, I wish to track the movement of three balloons (red, green and blue). I have a basic patch that motion tracks but this does not see to do what i wish.

The idea is that the three balloons will be tethered to the ground and filled with helium. A camera will be placed above looking directly down at them. If i can track the balloons individually then I can use the x,y coords. for other purposes. Does anyone have a patch that might help me do this? I was thinking maybe the patch should pick out the RGB value of the video feed. I'm a noob to MAX MSP.

Here is a visual representation...

[img]index.php?t=getfile&id=761&private=0[/img]

Any help will be greatly appreciated!!!!
Many thanks

Jonathan.