blob tracking w/ Kinect - for responsive installation

Hi,

i am working on a responsive installation (school project) where i need to track motion in a certain area. the Kinect is required to be used for that. i started to work on blob tracking, though i need advice and help to continue. i need to track both presence in the area and need to divide the area into two - an outer and an inner circle. in the inner circle i would like to see the numbers of people (as blobs) - also i wish to see if there is movement from the outer circle into the inner one.

as i am unexperienced with jitter, any help/hints would be appreciated.

thanks in advance
edit

here is my patch, i have so far:

[mod - removed uncompressed patch]