lee@rochester.UUCP (Lee Moore) (04/11/85)
Does anybody know about making holograms by computer? I remember seeing
an article from about 10 years ago which showed some crude computer
generated holograms. I believe the work was done at Bell Labs.
My roomate (who is an Optics grad. student) thinks that it can be done
but we don't have a powerful enough film recorder. He doesn't know of
anybody who has hacked the geometry, though.
Any leads would be appreciated.
-=lee
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Physical: 43 01' 40'' N, 77 37' 49'' Wgwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>) (04/12/85)
> Does anybody know about making holograms by computer? I had a literature search done and turned up zillions of references to computer-generated holograms and kinoforms. Any good holography text will have some references and probably a couple of pictures. There is one book that I unfortunately don't have beside me at the moment with a picture of a sample computer-generated hologram being reconstructed very vividly under a Tensor desk lamp. > My roomate (who is an Optics grad. student) thinks that it can be done > but we don't have a powerful enough film recorder. He doesn't know of > anybody who has hacked the geometry, though. ? The optics require precise control, but the geometry is trivial! A couple of months back I suggested a mailing list for this topic but only got a couple of responses.
ken@turtlevax.UUCP (Ken Turkowski) (04/14/85)
In article <7931@rochester.UUCP> lee@rochester.UUCP (Lee Moore) writes: >Does anybody know about making holograms by computer? I remember seeing >an article from about 10 years ago which showed some crude computer >generated holograms. I believe the work was done at Bell Labs. 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. -- Ken Turkowski @ CADLINC, Menlo Park, CA UUCP: {amd,decwrl,hplabs,nsc,seismo,spar}!turtlevax!ken ARPA: turtlevax!ken@DECWRL.ARPA
thomas@utah-gr.UUCP (Spencer W. Thomas) (04/14/85)
I did some computer-generated holography way back when I was a senior in
college. It was pretty trivial - just did multi-plane stuff using
Fresnel xforms (i.e., 2 1/2 D). I plotted the results on a Calcomp
plotter, then reduced them photographically (so much for needing a
"precise film recorder"). Considering their size (grid of 64x64, as I
recall), the results were pretty good -- I could even get a virtual
image reconstruction by looking through the hologram at a bright
non-coherent point source.
The issue of doing a correct 3-D implementation with hidden surfaces,
shading, &c is, in my humble opinion, much harder (not that I've thought
about it too much). You need, at least, much greater computing
resources (just a 3-D FFT, which is minimally what you need, is
O((n*log(n))^3). This grows pretty rapidly for reasonable values of n.)
--
=Spencer ({ihnp4,decvax}!utah-cs!thomas, thomas@utah-cs.ARPA)
"The meaning and design of a problem seem not to lie in the solution,
but in our working at it incessantly." -- Jungsea@browngr.UUCP (Scott E. Anderson) (04/14/85)
I like the idea of a mailing list for the topic! -- Scott E. Anderson brunix!browngr!sea
thomas@utah-gr.UUCP (Spencer W. Thomas) (04/16/85)
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 could, of course, be wrong about this, and I would be much more impressed by the hologram if I were. My impression when I saw it last summer, however, was that it was a strip hologram. -- =Spencer ({ihnp4,decvax}!utah-cs!thomas, thomas@utah-cs.ARPA) "Controversy equalizes fools and wise men in the same way -- *and the fools know it*." -- Oliver Wendell Holmes
keithd@cadovax.UUCP (Keith Doyle) (04/18/85)
[............] > 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
mae@weitek.UUCP (Mike Ekberg) (04/23/85)
> In article <7931@rochester.UUCP> lee@rochester.UUCP (Lee Moore) writes: > >Does anybody know about making holograms by computer? I remember seeing > >an article from about 10 years ago which showed some crude computer > >generated holograms. I believe the work was done at Bell Labs. > > 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. > -- > > Ken Turkowski @ CADLINC, Menlo Park, CA > UUCP: {amd,decwrl,hplabs,nsc,seismo,spar}!turtlevax!ken > ARPA: turtlevax!ken@DECWRL.ARPA Some years ago, Atari purchased a lot of the patents for holography in anticipation of a home game using that technology. The game was never marketed, and God only knows who has the rights now. Could be Warner, Trammiel/Atari Corp., Atari Coin-op(now owned by NAMCO), or the rights could have been sold to some other company. Mike Ekberg @ Weitek, Sunnyvale, CA UUCP: {amd,decwrl,hplabs,nsc,seismo,spar}!turtlevax!weitek!mae "Over 25,000 quotations may be found in Bartlett's Quotations"