Re: TECH3D digest 56

[T3D Jose Joaquín Lunazzi <lunazzi@xxxxxxxxxxxxxx>]

> >Date: Fri, 13 Dec 1996 17:58:54 -0800
> >From: T3D Jose asked:
> >
> >Dear 3Ders,
> >           I made a presentation on applications of my diffractive
> >screens at SHARP in Tokyo, referring my point of view on the
> >limitations os stereo 3D images.
> >My claim is that it will never be possible to show 3D without
> >goggles to more than one observer at a time, due to the lack of
> >continuity on the transition between viewpoints.
> 
> Larry Berlin <lberlin@xxxxxxxxx> added:  Interesting premise.


>Jose':  >And that the scene will also never be seen in full depth.
> 
> Larry:  What is meant by *full depth*? I'm acquainted with stereo
> scenes and consider that I've seen the *full depth* but I think I don't
> understand your reference here.
> 

Jose: I meant full depth as seing in the same scene, simultaneously,
images as close to you as your accomodation allows, and as far as the
horizont [minimum   8-)].
We know there is a circle whose radius put a limit on the distance
between corresponding points in a stereo pair.  This is not a problem in
a natural scene because the observer's eyes converges toward the object
being focused, discarding also the presence of double images in front or
behind.    

>Jose':  >An executive ask me then if it would be possible to see images
> >behind the screen because stereo can not do that.
> 
> Larry:  Stereo most certainly does have that capability. Again, perhaps
> I'm not understanding you but I look at 3D behind the screen and in front of
> the screen all the time and it seems fairly normal for 3D imaging to be in
> either place. That's what 3D is all about, not being limited to the screen
> itself.
> 
> >
> Jose':  >I answered that I do not know about stereo (in fact, I always saw
> >images in front of the screen, never a person or car goin deep
> >behind) but that I did images more than 30m behind the diffractive
> >screen, and maybe more would be possible.
> >
> >Can you tell me about the possibility of putting an object in a
> >stereo scene, in a movie f.ex., going behind the screen?.
> 
> Larry:  Visit my web pages  ( http://www.sonic.net/~lberlin/
> http://3dzine.simplenet.com/) or many of the other web pages of P3D and
> T3D members who have a large variety of images and presentations. Generally,
> if the stereo image is being viewed in a parallel viewing method, it exists
> behind the screen and if you view with crossed technique it is in front of
> the screen. The use of the new interlaced tehcnology makes it possible to
> place the stereo image on the whole screen instead of using side by side
> pairs. I'm sure there is a lot of latitude for design in which you can do
> both in front of and behind the screen.
> 

Jose': I am "crossed viewer", visited some of your figures, but they
come very slow to me.  I do not know why crossed viewing can not allow
images behind, parallel in front, but my aim is related to classical 3D
cinematography, although I am interested also in the present techniques.
The latter must in the end give the same result, I think.
Seems to me that it is not possible one subject being well in front of
the scene, while other goes very far behind, and the observer can choose
which one of both to see.

>Jose': >By the way, let me comment that SHARP has a very nice show room there
> >and, although they mention 3D as images for the utopic future, they
> >do not even show there the experimental 3Dgoggless TV made by SHARP
> >in England.   ...
> 
> Larry: Typical one-eyed thinking even on the part of companies
> supposedly working on 3D technology. .....

I agree, very nice phrase "one-eyed thinking"   '-)


>Jose': >SHARP model uses Fresnel almost plane lenses.............
> 
> Larry:   ....  Then the laser
> scanning systems that project the image directly into the eye will have a
> good chance to exceed whatever lenticulars may accomplish.

Which system is that?. Please give me a reference.

Sorry for the long novel ... Let me compensate with a short signature.


Jose'
 
lunazzi@xxxxxxxxxxxxx (for Netscape or large files, eternal address)


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