P3D Re: 3D with DLP projectors

[Larry Berlin <lberlin@xxxxxxxxx>]

>Date: Thu, 25 Feb 1999 
>From: Andrew Woods <andrew@xxxxxxxxxxxxxxxxxxxxx>
>...................
>Larry Berlin wrote:
>> Does anyone on the list have first hand experience with Digital Light
>> Projection and stereo? ..................


>The DLP projectors I've had experience with projected unpolarised light 
>but this may vary from machine to machine.  Put a polariser at the lens 
>of the projector and you will soon see what the nature of projector's
>output polarisation is............................snip..........
>
>Forget field-sequential with DLP.  Most DLP projectors update the DMD
>sequentially (like a CRT) but unlike a CRT, light comes from a particular
>pixel for the entire period of the field (except when greyscales are
>projected).  "pixels" in CRT projectors receive a quick burst of energy
>from the electron beam and hence there is a "bit" of a dead period between
>fields (during the vertical interval).  You don't get any dead period
>with DLP projectors.
>
>Cheers,
>Andrew Woods.

*****  Interesting, and thanks Andrew. 

For additional information I just got an email from 3D-Video, the same folks
who provide the Camcorder attachment for shooting stereo video at home. I
had asked about sending computer content to a screen via a DLP system...

>SVGA is a different animal.  Depending on the application, it is almost
>better to use a single CRT with SVGA output because it can run at 120
>Hz.  The reason for the complication is that SVGA is not easily
>demultiplexed into two the signals required for stereo projection.
>However, we have the capability to do both.  Again, it just depends on
>the application.
>
>Regarding DLP, the systems you see on our web site
>http://www.3-dvideo.com/projspec.html are DLP systems.  They work great.

****   His reference to two signals refers to polarization, which according
to him works fine. It seems his information coincides with yours on the
field sequential bit. The demuxing he mentions here costs about $8,000-$10,000.

I asked him about using DLP with anaglyphic projection, but he had no
experience with that and couldn't answer the question. Anyone try anaglyphic
with DLP? I'm assuming that with Quartz0Halogen lighting and a color wheel
process for color it would be much better than NTSC. Anyone try it yet?

Larry Berlin

Email: lberlin@xxxxxxxxx
http://www.sonic.net/~lberlin/
http://3dzine.simplenet.com/


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