[photo-3d] Re: 3D vision

[Bruce Springsteen <bsspringsteen@xxxxxxxxx>]

I'm inclined to agree with the logic of Abram's argument, regarding the
prospect of Rogers' daughter seeing stereoscopically, even if the
mechanical challenge of the experiment were addressed.  But allowing for
John Rupkalvis' philosophy of "never say never", and assuming for the sake
of discussion that there may be unknown potential for her brain to learn
to process stereo input, I think an external mechanical problem may still
exist.

As Abram pointed out, retinal disparities, not vergence changes, are the
basis of stereopsis.  But as a practical matter, the ability to "scan" a
stereo scene binocularly by changing vergence as objects at various depths
are fixed upon, is critical to the experience.  This requires that the
optic path change dynamically, at the will of the viewer, while examining
a pair.  Rogers indicated that his daughter really hasn't acquired much
control over the muscles of the affected eye.  Would her attempts be
compromised or thwarted by an inability to scan the view?   For a thought
experiment about the mechanical problem, assume a patient with a proven
history of stereopsis, whose eyes become permanently immoveable at a fixed
divergent angle.  Is it possible, using any of the devices described so
far, or any others you can describe, to make a viewer where the images are
moved continuously before the eyes to bring different parts of the scene
to fusion - when the eyes cannot do it themselves?  And do it fluidly so
as to emulate the automatic effects of changing vergence in stereo
scanning?  Rogers did refer to being able to *change* the direction of the
optical paths in his appeal for a device, if I understood right, and that
raised the question for me.

Bruce

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