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Path: utzoo!hoptoad!amdcad!ames!sgi!mrx@inferno.SGI.COM
From: mrx@inferno.SGI.COM (induced catalepsy)
Newsgroups: comp.windows.misc,comp.sys.mac,alt.cyberpunk
Subject: Re: computer-generated holograms (was Re: replacing the desktop metaphor)
Keywords: desktop metaphor, graphical interfaces, computing environments
Message-ID: <24412@sgi.SGI.COM>
Date: 6 Jan 89 23:14:53 GMT
References: <454@blake.acs.washington.edu> <17939@glacier.STANFORD.EDU> <3660@ttidca.TTI.COM>
Sender: daemon@sgi.SGI.COM
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 38

hollombe@ttidca.TTI.COM (The Polymath) writes:
> barmar@kulla.think.com.UUCP (Barry Margolin) writes:
> } hollombe@ttidcb.tti.com (The Polymath) writes:
> }>  I'm not sure it's even
> }>theoretically possible, let alone feasible.
> }
> }Well, it's been done.  A couple of years ago I saw a
> }computer-generated hologram on display at the MIT Media Laboratory.
> }I believe it was static (i.e. like a photograph), not dynamic (like an
> }animated display).  I don't know anything about the technology used to
> }produce it.
> 
> I was refering to using an LCD as the medium for displaying a hologram.
> Other technologies are coming right along.  I think your example is a
> system under development for General Motors.

Indeed.  The process for making computer-generated holograms
is fairly straightforward; you just have to simulate the
interference pattern that is produced by traditional 
holographic methods (fourier transforms, anyone?), print it out
on some medium (enlarged), and optically or electronically
reduce it to the appropriate size on film.  Computer-generated
holograms of this sort have been around since the mid-seventies,
or possibly earlier (I forget).

LCD is a different matter; holographic film has
a resolution of at least 3000 grains to the inch.
we definitely have a way to go before we can
create such resolution in any kind of dynamic media.


			Robert Reimann
			rmr@inferno.sgi.com
--


mrx@inferno.sgi.com
rmr@inferno.sgi.com