tracking with Jitter?!

Hi!
For a project at university I have to develope a part of an "exhibition", where I need to track relativly fast objects in front of a static backround.
Beeing a complet jitter-newbie I find it pretty difficult to get down to what I need:

We try to build a big window behind which cars pass by (@ the moment in a model of course). These we want to mask (track) and use the outlines to generate video output which is to be projected onto that window, kind of overlapping the driving car. The aim is to visualise things like the way air is pushed in a tunnel by cars driving through it.

Sorry for writing mistakes and comprehension problems!
I'd be absolutely thankfull for any given hint on how to solve my problems:

-tracking/masking of moving object in front of static background,
-using generated info to modify output.

thanks a lot for any possible help

cheers Philipp