Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site cadovax.UUCP
Path: utzoo!linus!philabs!cmcl2!seismo!harvard!talcott!panda!genrad!decvax!ittvax!dcdwest!sdcsvax!sdcrdcf!trwrb!trwrba!cadovax!keithd
From: keithd@cadovax.UUCP (Keith Doyle)
Newsgroups: net.graphics
Subject: Re: holography
Message-ID: <540@cadovax.UUCP>
Date: Wed, 17-Apr-85 21:37:53 EST
Article-I.D.: cadovax.540
Posted: Wed Apr 17 21:37:53 1985
Date-Received: Sun, 21-Apr-85 04:15:30 EST
References: <7931@rochester.UUCP> <728@turtlevax.UUCP>, <1415@utah-gr.UUCP>
Organization: Contel Cado, Torrance, CA
Lines: 39

[............]
> In article <728@turtlevax.UUCP> ken@turtlevax.UUCP (Ken Turkowski) writes:
> >Last year Cray research displayed a computer generated hologram at SIGGRAPH.
> >Your might want to contact them for info on hologram production and product
> >literature.
> 
> I think that this hologram was actually a "strip hologram".  That is, a
> number of tall, skinny holograms were made of essentially 2d scenes,
> then these were placed next to each other to get the 3d effect.  Since
> each hologram is tall and skinny, there is no 3d effect from an
> individual strip, but the stereo effect caused by each eye looking
> through a different strip causes the 3d appearance of the image.  The
> acid test here would be to see if you get different points of view by
> moving your head up and down.

I've heard these referred to as 'multiplex' holograms, and I've seen
one that was computer generated.  Looked like they used a Tektronix
4010 to generate it.  Not to impressive, it had a figure with an
iris that opened and closed as the hologram was rotated, and a heart
that would pass through the iris when it was fully open.  One cute 
capability of these holograms is that you can change the picture
slightly on each 'strip' and then by rotating the hologram, you get
simple animation.  (ever seen 'the kiss'? apparently the most prevalent
hologram of this kind out there.  Everywhere I have ever seen multiplex
holograms, 'the kiss' has been there, even in the Edmund Scientific
catalog.)  I bumped into some of the people who were making such holograms
in San Francisco once, and suggested they market them as beer signs.  They
apparently had grander visions of their marketable use, and took such a
suggestion as a slight insult (primma donna artiste).  It's a shame, though
they would probably made a lot more money in that sort of advertising.
Note that these holograms were used in the movie 'Logans Run', but I didn't
think they film photographed very well.  You could see the seams where the
ends of the holograms were joined together, and they seemed sort of foggy,
either the light was bad, or there were too many fingerprints on them.  Still,
a cute gimmick anyway.

Keith Doyle
#  {ucbvax,ihnp4,decvax}!trwrb!cadovax!keithd