Unless someone here has experience with OpenCV on CE / Windows Mobile (unlikely, but possible), then your best bet is to ask the
OpenCV User Group[
^]. I would start there and then come back here if you get no joy.
I'm betting it will need a bit more processing power than ARM generally gives - despite the impressive price/performance ratio, a laptop generally beats embedded systems hands down on processing and memory. Video stuff generally needs a good chunk of both...
It's open source, so why not grab a copy, and give it a try anyway - you might be lucky!