Date: Fri, 08 Jun 2001 09:56:22 -0400
Author: Gerald Zani
Subject: Re: 3D video by polarised light
I have not tried the 3D video method you describe. I saw a 3D method
in 1996 at Notre Dame U. that uses two cross polarized slide projectors,
a silver screen, and polarized viewing glasses.
Have you tried this before trying the video method?
I did not know that RGB video is polarized. You might try it first without
the RGB depolarizer? If you need to depolarize the RGB components I
believe you can
use either a 1/4 wave plate or a circular polarizer, which contains a 1/4
Here is some info on 3D:
BTW I think that one of my faculty, Hank Gerritsen, will be visiting your
At 12:17 PM 6/8/2001 +1200, you wrote:
>I have been asked by a person here in Christchurch, New Zealand, about
>projecting 2 cross polarised video pictures in order to allow 3D viewing. He
>proposes to do the following:-
>1) Attach a mirror arrangement to the front of a video camera to record a
>picture split horizontally so as to get two 8:3 aspect ratio pictures
>the usual single 4:3 ratio picture.
>2) Back project the resulting two frames (superimposed) by using the same
>device on a video projector and with crossed polaroid filters at 45 degrees
>(each way) to the vertical in each beam.
>3) Equip the viewers with crossed polaroid spectacles.
>4) Voila! 3D movies
>Assuming all this is possible, the problem he approached me with is that he
>finds that the individual RGB components from the video projector are already
>polarised independently of one another. He wants to unpolarise (depolarise?,
>randomize?) these three components and believes there is such a thing as a
>"homogeniser" which will do this. The back projection material will apparently
>retain polarisation but rotates it by 90 degrees in transmission.
>Has anyone out there tried anything like this? Did it prove feasible? Do
>Homogenisers exist? If so, where can they be obtained? Are they made of
>Your comments would be appreciated.
> Alistair Lightfoot, Teaching Support Technician,
> Physics & Astronomy, Teaching and Computer Support,
> University of Canterbury, Phone : +64 3 364-2987 ext. 7611
> Private Bag 4800, Fax : +64 3 364-2469
> Christchurch 8020, mailto:
> Zealand. http://www.phys.canterbury.ac.nz/people/A.Lightfoot.html
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