You can download my talk (6th workshop on Mathematics and Image Analysis, September 2006, Paris):
Image restoration and classification by topological asymptotic analysis
if you want a brief overview of the mathematical study and to see why we have a complexity in n.log(n) (where n is the size of the image/movie).
Note that this is an old presentation, you can contact me for a newer one (or have a look at my habilitation thesis webpage).
You can download here the corresponding (avi) movies. The numerical experiments have been performed on a laptop (2.0 GHz, 1 GB RAM), with Matlab 7.0, without optimization.
In C, on a faster laptop, the computation time has been divided by more than 1000.
The matlab, C and C-GPU codes are available under request.