Re: cross,parallel, and wall-eyed viewing

[P3D David C. Glick <xid@xxxxxxx>]

Gabriel said:

(quoting Pop Science)
>but if both eyes were to turn outward, 
>binocular vision would be lost, something the eyes, "central control
>won't allow," explains Dr.William Power, an instructor in ophthamology
>at Harvard Medical School.<<

>I remember that (Bill Ewald from Kodak) it was mentioned that, one could
>see beyond "infinity" by diverging ones eyes. If one did that and looked
>up at the stars it was mentioned that the stars would look closer to
>oneself. Now is this correct or is the above passage correct? Or are they
>both correct?!

I think Bill Ewald emphasized that he was talking about an extremely slight
divergence.  In his talk at Rochester NSA, he talked about positioning two
glass beads on a windowsill across the room from the viewer, spaced apart
from each other at exactly the viewer's interpupillary spacing.  A small
light behind the viewer would create a pinpoint of light in each one.  When
looking past them at the stars, those pinpoints would look like another star
at infinity.  Then if they were moved apart slightly, one's brain, refusing
or being unable to place the resulting artificial star beyond infinity,
would show that "star" at infinity, and would have to show all the real
stars being closer than infinity.  I think his point was that the brain
refuses to see something as being beyond infinity, even when the geometry
reported by the eyes tells the brain that it is.  (His talk, about stereo
cameras and displays as well as stereo vision, was fascinating.)

Assuming that the statement by Dr. Power is a generalization about
hypothetical large amounts of divergence, I don't think Ewald's statement
really contradicts him.

Dave Glick



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