eyes & keystoning

[T3D John Bercovitz <bercov@xxxxxxxxxxx>]

John R writes:
> Come to think of it, I wonder whether the human 
> visual system ever uses keystoning as a depth cue.

I don't know.  It still amazes me that we can turn 
our eyes and our heads and not get dizzy.  8-)

So how do you visualize keystoning as being a depth
cue?  (It feels funny calling it "keystoning" when
it's an image on a spherical surface but I don't
know what else to call it.)

Thanks,
John B


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