arliec@tekig.UUCP (Arlie Conner) (06/02/84)
I might be classified as an afficionado of 3D, probably not an
expert, so take what you get-
Firstly, attempts have been made at 3D displays, both moving and
still for over two centuries, and a summary of the early stuff is
not too realistic. The major developments led to the current
3D movie technologies, holography, and several wonderful contrap-
tions with enormous cuteness and very little practicality.
I did enjoy the Eastman-Kodak exhibit at EPCOT Center very much;
it consists of a 3D movie which you must view with *polarized*
glasses. This is the most viable system for mass viewing, and it
has excellent dimensionality (reality?) as well as a notable
absence of side-effects (as opposed to drugs ::=}} ).
I'm not much a fan of the red/green or red/blue glasses, although
it is supposedly possible to use these with a TV, and a single
projector is sufficient. I recall getting a headache trying to
watch one of these a while back and I don't think I was able to
synthesize the 3D effect at all. Maybe I had the glasses on inside-
out...
A couple of television systems have been proposed recently- two that
I've heard sketchy details about suggest compatibility with NTSC
(which will prevent me from being too excited at any rate) and seem
to make use of perceptual tricks (alluded to earlier) such as the
ability of the brain to ignore the left-eye image coming into the
right eye, and vice-versa.
A fairly reasonable quality display has been developed by a S.Cal.
company whose name escapes me at the moment, based on a vibrating
mirror (actually mounted above a large woofer, and forced to
oscillate at thirty Hertz, if I recall correctly). The first
versions were monochrome; color is possible, but the writing-rate
requirements favor a very high speed CRT, since each 'layer' of
the image must be written in a short amount of time (the depth is
created by time-multiplexing the image-planes).
Naturally, MIT has a fine alternative with two CRTs, and a special
headset which must be calibrated to the user (you must'nt move your
head either) but upon which you can paint and draw in true 3D! This
I saw demonstrated, including the 6-degree of freedom 'space-light-
pen' (wrong name, but descriptive nevertheless) sensor gizmo which
was used as the drawing/painting implement.
As for the advent of 3D holography, I'm not holding my breath. It's
not feasible to make holographic plates the size of a theatre screen,
for starters. Holograms the size of 70mm film are not very exciting,
unless you get very close. EVEN the Russian-made true-holographic
film which lasted 5 minutes and cost many thousands was only visible
by one viewer (subject matter was tropical fishtank, I believe) and
was of course green throughout. Holography is not the way to do this
kind of stuff, for many reasons.
As a simple philosophical/physics question, consider the ideal 3D
projection system: How many viewpoints are really necessary to
a) create the illusion of three dimensions,
b) allow the viewer to see different points of view as he
moves his head about in the 'theatre',
c) completely disorient the viewer and cause him/her to
suspend their disbeliefs, i.e. lose touch with the arm-
chair and spill their popcorn?
Viewpoints can be thougth of as eyes, cameras, CCD arrays, or even
holographic cameras, for the sake of answering the question posed.
Hope this partially answered the musings upon 3D, send any new
developments along for my scrapbooks,
Arlie Conner
!tekig!arliec
P.S. Did you know that humans do not develop stereo-spatial perception
until about six months of age; a Bell Labs researcher provided con-
ving study to show that the brain must learn to see in 3D.