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dameron

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Posted on Monday, December 10, 2001 - 7:00 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Acquire

$200 two 640x480 high color lcd projector panels
$200 two cheap 2000 lumen overhead projectors
$20 one db15 video Y type cable
$130 one 50" x 50" silver non-depolarizing screen
$30 two polarizing filters and a set of polarized
glasses

You will also need a computer capable of playing back your video or game and software capable of displaying stereo pairs in a side by side or above/below format.

Connect the projectors to the computer with the Y cable and point the projectors at the non-depolarizing screen. Load a test pattern and make sure the projected images align as closely as possible to one another. Turn on the computer and have the output simultaneously displayed on both lcd panels.

Your desktop size should accomodate the resolution of the images you are trying to project, i.e. if you are trying to project a stereo pair of 640 x 480 images side by side you would need a desktop size of 1280 x 1024 (or 960 if you can do that). If your lcd panels support scrolling the onscreen image to view any particular 640x480 portion of the larger desktop, and a lot of cheap panels can do this, simply scroll the image on one projector until it shows only the one 640x480 image (r) then tune the other panel until it shows only the other 640x480 image (l).

Place the polarizing filters over the overheads' lenses and put on your glasses. You should be pleasantly surprised at what you see...

If your lcd panels can't scroll a 640 x 480 window around the screen you can do the following: set your desktop size to 640 x 480 (your image may not look nearly as good, but hey, it'll work). Take some aluminum foil or other opaque material and block out an image on one of the lcd panels (r). Foil and scotch tape work fine for this. Your final image will only be a fraction of what it would be if you had panels that could scroll, but it will be stereoscopic.

Finally, if you can find them, (they are rare and really worth it) get two panels capable of 1024 x 768 or higher for obvious reasons for around $300 each.

Stereoquake 3 should work easily. Does anyone know of an easy way to get other opengl games or programs to display side by side??

-dameron

(having a world of fun...)
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dameron

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Posted on Monday, December 10, 2001 - 7:32 pm:   Edit PostDelete PostView Post/Check IPPrint Post

I skipped a step. You have to block out the other panel's opposite side (l) with the scotch tape and foil method as well for it to work. Also higher lumen projectors will allow you to move the projectors further from the screen (and also use a bigger screen although they get pretty expensive)where they are much easier to adjust.

Putting the projectors on a lazy susan helps as long as you can rig a method to lock them in place once they're aligned properly.

Also, I'm looking into using dscaler to accomplish the same task using two computers, although I think the quality might suffer a bit.

-dameron
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Anonymous

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Posted on Monday, December 10, 2001 - 10:56 pm:   Edit PostDelete PostView Post/Check IPPrint Post

I cannot find high color lcd projector panels for 100$ each one.
Can you help me?
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dameron

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Posted on Monday, December 10, 2001 - 11:26 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Check ebay, I've gotten four off there in the last year, prices:

$56 for 640x480 2 million colors, db15/svideo
$75 for 640x480 16 million colors, db15 only
$100 for 640x480, 2 million, db15/svideo,audio,mac
$215 for 1024x768, 1.4 million, db15

http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1675777819

A very nice panel for $160 with "buy it now".

If you watch and know which models are good you should be able to catch a couple in a week or so.

BTW, these panels can also project dvd, ps2, or most any other video source. My initial setup was a panel I picked up surplus from a school, it did 640x480 at 2 million colors for $100, I coupled it with a $120 dollar (retail) 2000 lumen overhead and could watch tv/dvd/pc/games at about 90"x90" on my wall at very nice quality with the blinds pulled or at night. A higher lumen projector only helps.

FYI, the Sharp QA series over QA-1000, the proxima ovation series 800+ and the nview 115+ are all acceptable, check google for specification on a panel.

-dameron
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Andreas Schulz

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Posted on Tuesday, December 11, 2001 - 11:40 am:   Edit PostDelete PostView Post/Check IPPrint Post

That leaves the problem of getting overhead projectors (well, maybe no problem at educational institutions..), and to explain to my wife why to put two of them into our living-room ;-)
Note that light coming out of LCD panels is already polarized, so with two different panels you may be lucky and already have different polarization. Otherwise, the polarizers will have to be rotated at +/-45deg, blocking half of the light.
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Anonymous

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Posted on Tuesday, December 11, 2001 - 11:41 am:   Edit PostDelete PostView Post/Check IPPrint Post

Thank you.
I live in europe, you do think I can easly buy them anyway?
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Anonymous

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Posted on Tuesday, December 11, 2001 - 1:18 pm:   Edit PostDelete PostView Post/Check IPPrint Post

where do you buy the polarize filters?
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Giorgio Bogoni

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Posted on Tuesday, December 11, 2001 - 5:10 pm:   Edit PostDelete PostView Post/Check IPPrint Post

No need for polarizing filters.
You have the right polarization on one LCD panel, just flip the other one and adjust your side-by-side image in the right way.
Giorgio.

(I not able to find cheap LCD panels too, I live in Italy)
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Anonymous

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Posted on Thursday, December 13, 2001 - 9:40 am:   Edit PostDelete PostView Post/Check IPPrint Post

Giorgio,
I'm not sure what you mean I'm new to all this..
I was originally thinking about the cheaper infocus dlp units.... But you are saying this could work with the even cheaper lcd units?
How would one know if one projector has the right polarization and what do you mean by flip the other one??
I'm in the USA
Trying to project interlaced 3d video
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Giorgio Bogoni

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Posted on Thursday, December 13, 2001 - 9:45 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Anonymous,
I wasn't speaking about video-projectors but LCD panels and overhead projectors.
if you use two LCD panel with a light behind and, let's say, rotate one of them I aspect a 45/135° polarization of projected images.
Even some LCD video-projectors may have the correct light polarization, you have to check it for one eye and rotate the light polarization caming out from the other projector with a half-wave retarder (but I've never tried this!).
DLP video-projectors are the simplest solution: the output no polarized light, you can but two of them and use standard polarized filters in front of both of them.
If you have an interlaced video you have to buy an expensive de-multiplexer or turn your video to side-by-side format and play it with a dual-head graphic card (connecting the two projectors to VGA outputs).
Regards,
Giorgio.
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Giorgio Bogoni

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Posted on Thursday, December 13, 2001 - 9:47 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Another thing:
VREX sells a 3D projector (just connect it and play your 3D interlaced video) and Barco pre-polarized LCD video-projectors (you have to buy the left-one and the right-one) .... all very expensive solutions!
Giorgio.
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Anonymous

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Posted on Friday, December 14, 2001 - 12:22 pm:   Edit PostDelete PostView Post/Check IPPrint Post

where does one buy the the polarized filters?
If convert video to sidebyside how insure left eye goes to projector 1 and right to projector 2?
use card like matrox 550?
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Giorgio Bogoni

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Posted on Saturday, December 15, 2001 - 11:31 pm:   Edit PostDelete PostView Post/Check IPPrint Post

The polarized filters are phographic stuff.
Set an extended desktop 1600x600 and play at full screen your side-by-side video connecting two 800 x 600 projectors.
I really don't know about matrox 550 but if it's a dual-head card it will work.
Giorgio.
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Anonymous

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Posted on Monday, December 17, 2001 - 2:14 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Giorqio , Thanks for your reply however I'm trying to get 1000% specific since I'm a newbie here. Do you have a website/phone # of a company to call to order these polarized filters from?
Are there different types of filters? how I'm I to be sure they have the same properties as Polarized viewing glasses I would get?
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Giorgio Bogoni

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Posted on Monday, December 17, 2001 - 11:22 pm:   Edit PostDelete PostView Post/Check IPPrint Post

You can start trying whith the polarized filters of a pair of glasses!
Try www.reel3-d.com ... but I don't like sponsor anyone.
There are linear and circular polarizer, look for the linear ones.
Giorgio.
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Anonymous

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Posted on Thursday, December 20, 2001 - 8:03 am:   Edit PostDelete PostView Post/Check IPPrint Post

Interesting reel3-d says the filters work with dlp projectors but not lcd
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Giorgio Bogoni

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Posted on Thursday, December 20, 2001 - 9:26 am:   Edit PostDelete PostView Post/Check IPPrint Post

Because they suppose LCD projectors outputs polarized light .... but LCD projectors don't beware all in the same way.
Giorgio.
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Andreas Petersik

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Posted on Friday, December 21, 2001 - 10:24 am:   Edit PostDelete PostView Post/Check IPPrint Post

I have experiences in using LCD and DLP projectors. No problems so far. LCDs are usually not polarized with 45 or 135°, so no problem. The international standard for polarized projection is 45° and 135° angle. If you use other angles, you will need to build all glasses yourself! Do not do this!
In my LCD projectors the different colors were polarized in different directions. E.g. green 90°, blue 0° and red 180°. So color changes when rotating the filter, but when you are at 45° or at 135° there is no color problem, even with LCD.
To be sure, you should test this before buying of course!
DLP is no problem at all!

If you use side-by-side or above-below formats, you should get a Matrox DualHead board. It works well! You simply extend your desktop in the display settings to either double-horizontal*vertical resolution or to horizontal*double-vertical.
If you want to use page-flipping OpenGL-applications, you should get a GeForce dualhead board and RivaTuner from www.nvworld.ru
It looks like it is possible to output left and right eye to the both outputs with Nvidias drivers. I have not tested this yet, but I will do this as soon as my new graphics board arrives.

BTW: In Germany you can order polarized filters and glasses at:
http://www.stereo-optik-grosch.de

Have Fun!

Andreas Petersik
http://www.stereophotography.com
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Alexander Oest

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Posted on Friday, December 21, 2001 - 10:56 am:   Edit PostDelete PostView Post/Check IPPrint Post

Andreas Petersik,

Do you mean it will be possible to output right resp. left eye's perspictives on all Direct3D and OpenGL applications to separate outputs with Nvidia driver? (i.e. not just the OpenGL apps with built-in stereo on RivaTuner)

That would really be something!

Alex
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Anonymous

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Posted on Thursday, December 27, 2001 - 9:17 am:   Edit PostDelete PostView Post/Check IPPrint Post

Andreas Thanks for your info, I look forward to hearing how the dual geforce board works out.
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Anonymous

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Posted on Wednesday, January 02, 2002 - 3:43 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Hello Alexander,

maybe it works with OpenGL apps with build-in stereo only. I don't know. I am still waiting for my dual head board...
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dameron

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Posted on Thursday, January 03, 2002 - 7:19 pm:   Edit PostDelete PostView Post/Check IPPrint Post

This program

http://www.realtimesoft.com/videosaver

will allow you to stretch any video across two (or more) monitors. I've tried it with my desktop setup and it works great and even has a playlist. It should allow you to play side by side avi files on two monitors with no trouble. Unfortunately they've bundled it as a screen saver so it's a little cumbersome to use, but it does work.

-dameron

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