Movement tracking using webcam (no kinect)

Hi, I am following this interactive painting tutorial but would like to use my computer webcam instead of a mouse to control the painting: h ttps://www.youtube.com/watch?v=7SYZKvjnPog&lc=Ugzq1z4JJArUF4zAuLF4AaABAg.9lpzFdp-gww9lqQw0PHFHm

I am not sure how to do this (motion detection, x and y position eg moving hands or arms) using the blob track TOP, and which TOP to connect the blob track to. Any tips would be greatly appreciated!

-Claire