Object Tracking with SimpleCV (White Ball)

balltrack.py

'''
This is how to track a white ball example using SimpleCV

The parameters may need to be adjusted to match the RGB color
of your object.

The demo video can be found at:
http://www.youtube.com/watch?v=jihxqg3kr-g
'''
print __doc__

import SimpleCV

display = SimpleCV.Display()
cam = SimpleCV.Camera()
normaldisplay = True

while display.isNotDone():

	if display.mouseRight:
		normaldisplay = not(normaldisplay)
		print "Display Mode:", "Normal" if normaldisplay else "Segmented" 
	
	img = cam.getImage().flipHorizontal()
	dist = img.colorDistance(SimpleCV.Color.BLACK).dilate(2)
	segmented = dist.stretch(200,255)
	blobs = segmented.findBlobs()
	if blobs:
		circles = blobs.filter([b.isCircle(0.2) for b in blobs])
		if circles:
			img.drawCircle((circles[-1].x, circles[-1].y), circles[-1].radius(),SimpleCV.Color.BLUE,3)

	if normaldisplay:
		img.show()
	else:
		segmented.show()

how would you change the colour of the ball it is trying to track?

This is truly great, but my windows is lagging compared to your video. I'm going to try this on a PCDuino mini, with a wifi arduCAM once I recieve my order from China; it will be a while. I tried editing the line, as posted above and got a black screen:
if circles:
circles.draw()
img.drawCircle((circles[-1].x, circles[-1].y), circles[-1].radius(),SimpleCV.Color.BLUE,3)

I also tried it without the parameters with the same black screen result, can you please fill in what I have omitted?