Oh, and by the way:
I'd like to be able to take stereo pairs of the ground from one of my model planes, and generate reasonably good digital elevation data from the images.
For proper resolution of the resulting data set, would you need the photos to be farther apart than your typical stereo pair meant for human eyes? i.e., a very big airplane with a camera on each wingtip, or two photos taken sequentially as the aircraft moves?
(For instance, to get a proper 3D effect from
this geographical feature, the two photos had to be miles apart, taken a few seconds apart from the window of an airliner.)