Good stereo public relations

[P3D Dr. George A. Themelis <fj834@xxxxxxxxxxxxxxxxxxxxx>]

Thank you for your responses to my question regarding complain of headaches
despite precision mounting in projection (nice summary Ron!)  I agree and
would accept (with slight reservations) many of the proposed reasons as an
explanation for headaches:

- Too much stretch (the person with the headache was in the very back of 
  the room).
- Disconnection of convergence and focusing (more of a  problem in a
  viewer or when sitting very close to the screen).
- Defective glasses (it is possible) leading to excessive ghosting.
- Headache from just wearing glasses (maybe my wife is correct for a
  change! :-)
- Inability to keep the head leveled.
- Exposure to too many images over a short period of time.
- Lack of certain non-stereoscopic cues present in "real life" like motion,
  etc. (I am a bit skeptical with this but will include it in my list).

As we, more experienced stereo viewers, get exposed to more and more stereo
pictures we are getting immune to some of these factors that can give a
novice a headache just as we are getting immune to stretch and other
"deformations".  Even experienced stereo photographers like Ron Doerfler
report headache-like symptoms in certain situations.  It is amazing that
most of us can sit and watch stereoscopic projection in the NSA conventions
during an entire day!   I am also a little bit concerned about the
commercial success of 2 hour long 3d movies if some people cannot stand a
45 minute nicely presented slide projection.  I think there are reported
negative reactions to IMAX 3D movies too?

Regarding the sensitivity to the inability of some people to view stereo or
get negative reactions, I think Peter Abrahams summed it best:

>I think you have to deal with these issues in your introduction, even if
>that somewhat 'pulls the rug out' from under your thesis.  Open the talk by
>noting that there is an auxiliary to the audience's field of endeavor that
>uses stereo imagery.  It can be highly effective, but there is a small
>percentage of the population who are incapable of stereo vision, and a
>small percentage who find these presentations to be uncomfortable.  Say
>that, in spite of these notable problems with the technique, the
>effectiveness of stereo is such that the audience should consider its use.

Thanks Peter!  I will always remember to do this in my public presentations
for general audiences.

George Themelis


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