T3D Perspective on extreem 3d

[John Toeppen <toeppen@xxxxxxxx>]

Accommodation may account for the perceptual problem with extreme depth
disparity in an image.  Our eyes attempt to refocus for different
convergences.  We are familiar with interpreting an image in a 2D plane
as though it were 3D.  Perhaps we try to refocus when we see stereo in
the
extreme.

I might add that if the stereo view is bright, our eyes stop down, and
refocus does not result in a blurred image or discrepancy.  Rear
projection 
stereo and other methods can effectively use brightness to minimize
accommodation problems. 

This refocus issue could explain why it is difficult to do good macro 
(in a single exposure) with a normal Realist. Focus on near objects
requires more
focus adjustment of our eye's lens.  I can see an object at eight inches
from my nose, but my Realist can't (easily)produce a good view of the
same.
It may also be a distortion problem.

This kind of loops back to a previous topic regarding telecentric
systems
and the "ortho" perspective. And the electron microscope tilt issue was
the
same thing.  If one wants to preserve scale (exact dimension
preservation independant
 of distance) use long lenses at low angles or use telecentric optics.
Otherwise, 
the "distortion" (field curvature) in the viewing system may not match
the 
distortion in the image.Close objects are supposed to look bigger
because 
they are close - telecentric effects eliminate this cue.  

You have to refocus for different convergences in real life.  And this
is important
up close.  A quick refocus of my red button viewer certainly can help. 
Interoccular
adjustments help too.  But the real world still has information that we
can't
quite capture and playback. But it is getting better all of the time.

John Toeppen
http://members.home.com/holographics/


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End of TECH-3D Digest 498
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