RE: embedded flight computer for autonomous helicopter
about vision:
detecting specially good contrast objects from ccd camera image should be simple. For example you can mark the landing point (or whatever point) with IR diode. mod the ccd camera to work at IR.
From the image you just pick up the max illumination coordinate.
I have no experiment nor details, but only the idea that you could also slowly blink the IR diode to send a "ID" of the point to CCD by rougly measuring the blink rate.
Jyrki