Re: [tech-3d] Re: Terms and Definitions

[John Toeppen <toeppen@xxxxxxxx>]

Bruce Springsteen wrote:
> 
> Abram,  >(is still)> probably slightly mortified...
 Personalities intrude despite our best attempts at cold
> reason.  Even on Tech3D. ;-)
> 
> > John Toeppen:
> > >(...) a cheap trick to encourage membership

You know that it is fun to tease each other.  This way we prompt each
other to write and do interesting things.  Discussion of terms might
lead us into interesting topics.

> 
> Now I'm curious - how does accommodation figure into any of the competing
> definitions of "ortho?"  John Toeppen mentioned it as a factor in
> orthostereo and I let it pass, but it sounds like he might require more
> than even my "tautomorphic" condition would.  Can any stereoviewing scheme
> duplicate the variations in accommodation that occur in real space vision?

Classical holography accounts for accommodation.  Stereo does not record
that data in an easily reconstructable form.   When a slide viewer has
its focus set to the "hyperfocal" point (~=15ft) objects are close to
"as you see it"  Most people set the focus of their viewer to the
distance of  a newpaper or a monitor rather than 15ft.  People expect to
see flat images at about 2 feet, and have accepted this as correct image
viewing.  Further, most people prefer their eyes relaxed, and tend to
focus a viewer for comfort rather than image scale.  Arguments have been
made regarding the value of exercising our far field focus, but to some
of us our images just look better there.  The screen distance in
projection is responsible for the same effect, and weighs against image
size.

>... so, we seem to be raising the bar on stereo
> "reality" in a way that could throw our nomenclature into a real tizzy!
> 
OK.  Language has limits.  So do images and hardware.  There are some
advantages in considering accomodation by setting the "screen distance"
out as far as possible, maintaining a wide field of view, and retaining
sufficient resolution for fovial satisfaction.  A good bright view has
the distinct advantage of forcing they eyes to stop down so that if they
wanted to focus to match convergance they would still see sharp focus. 
If any of these things are not properly considered the stereo effect is
diminished.  Choose your trade-offs.

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

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