Motion capture + background subtraction

Some research to the topic:

1. Human Motion Capture Using a Combination of 2D Feature Tracking and 3D Visual Hull Reconstruction - very good link showing how to do subtraction, we might need just to use the 2D part. Looks very good, just we need to check how it would work in real time. http://www.mpi-inf.mpg.de/~theobalt/VisualHullTracking/index.html
2. Real-time background subtraction (Updated) - blog, shows piece of the flash code, the guy sounds convinced that it works pretty well. B&W, good real time response. http://blog.je2050.de/2006/10/10/real-time-background-substraction/
3. This guy has a blog with series of videos of his work: http://jorgecardoso.eu/blog/index.php?/categories/6-Processing
   It could be possible to contact him, he could be helpful. This is his contact: http://jorgecardoso.eu//

I think this wouldn't look naturally. As we are using very real pictures to create feeling of the real view to the open space, the subtraction wouldn't work well.