"Here Be Pixels" by Mario Klingemann is an interesting presentation from MAX 2008.
In it, Mario talks about using bitmaps and bitmapdata with cameras to do everything from a barcode reader to augmented reality. He doesn't cover the code, but does cover the theory and shows some implimentations, and references research that this was all built from.
I feel like I've just sat through an intensive lecture at university all over again - I did a motion capture project with much of the same technology back at university, so I found it very interesting to see just how far the same technologies could be taken.
Have a watch, if you have 56 minutes!