PIL speed and fears

[akhar]

I have been using pil for robtic vision, however due to a lack of funding my
project is not very far yet ( I have only been parcticing with static
images). Now I have been optimising code and all but (I am under windows) I
see some lag when I manipulate large images 640*480, what I do that I use
pil to split the image into three matrixes and then scan for specified
values and filter out others and discontinuities in them, the only real lag
apears in  two places in the code both coresponding to when I call PIL to
show the images resulting from the filters. I noticed that it tries to open
a dos session and then shows me the image in paint. I am afraid that for
phase two when I start using streams of images directly from the camera that
their will be an enormous lag. Is it only because of windows? should I be
using something else for realtime video streams like pySDL? or is it windows
and I should use freebsd to do this?

Regards
Akhar