🚀 go-pugleaf

In article <10428@ttidca.TTI.COM> ttidca.tti.com!schear%sdcsvax@ucsd.edu (Steve Schear) writes:
>
>In article <WEX.90Feb26123354@sitting.pws.bull.com> wex@sitting.pws.bull.com (Alan Wexelblat) writes:
>>
>>How about this: imagine that you have a desktop display that's capable of
>>creating a true 3D image of whatever you want.  The display is 3D
>>holographic for all viewers at all angles.  You can have whatever input
>>device(s) you like from today's catalogues.  What do you do with this setup?
>>
>Alan,
>
>A device similar to your discription was invent at MIT about ten years ago, and
                                                 ^^^^^^
Actually the one licensed by Genisco was designed by Larry Sher of BBN.
Research groups at Utah and UNC Chapel Hill also built models that worked
(and at least at UNC still work) in the lab.  The distinguishing feature
(IMHO) of the BBN version was that the vibrating mirror was hard plexiglass
rather than reflective mylar like the other two.

>subsequently build and sold by Genisco.  Although it did not permit a 360
>degree view, it did offer at least a 90 degree view.  Its best feature, 
>however,was its lack of a requirement for the viewer to wear glasses of any 
>type.
>
>The device used a high frame-rate monochrome CRT, which was viewed off the 
>surface of a mirror.  The mirror was mounted on a synchronously moving voice
>coil (30/60 cps, I believe).  The frames displayed on the monitor were slices
>of the 3D object.  Because the frames were presented at a high enough rate, 
and
>each frame was viewed at a different distance form the observer (the moving 
>mirror), the effect of of a rather solid object in 3-space was created within 
>the brain of the observer.
>
>I saw the device once and was quite impressed.  I don't know if its still 
 being sold.

Genisco sold only a few: Amoco, Phillips, Exxon, Seismic Acoustic Lab at 
UHouston, one medical outfit and one Japanese company are all I know of.
(Maybe Shell too)  Obviously back in the days when oil was booming.
I have seen The Utah, UNC, original BBN prototype and Genisco Spacegraph
demonstrated, and had the opportunity to try to use two of the Spacegraphs
and talk with those using a third.  

(1) Because the order of display must be stringently synchronized with the 
mirror period (pendulum style) and because lines in depth had to be broken 
into points, programming the beast for anything useful was a real pain.  
(Also not much software support.)

(2) Because it depends on superimposing images on the retina, there is no 
hidden surface removal so everything is ghostly see-thru.  Very distracting.

(3) For me at least, it is not a good trade to give up color to get stereo
depth perception.

I saw a paper at SPIE/SPSE Electronic Image Symposium last month by D. Venolia
and Lance Williams of Apple, titled "Virtual Integral Holography".  They 
pre-compute enough images to be able to slap up the appropriate pair from
a sensed viewing position on fairly modest equipment... so we're getting 
close.

Now to the point of the original post: I think this is an important question
to answer, to get development really started.  The two groups I have been
around a lot in the last fifteen years that have been trying to build 3D
physical models before the computer was anywhere close: Medical researchers
(and to a lesser extent prectioners) and exploration geophysicists.
In both applications I have seen people had trace their data on clear sheets,
put clear spacers of the appropriate thickness between, and then look through
the stack, trying to interpret the results.  That's what I call a motivated
customer.
Who has other applications with unfulfilled needs, as opposed to trying to
find an application for great technology?
Sam Uselton