3D projector using Infitec method?

HDI is circular polarized (RealD).

They could be LEDs too, but I think you need a color management system to deal with the different primaries (for each eye) and those are still $$. Maybe by the time they get the light sources cheaper, the CMS-on-a-chip will be cheap enough ...

Its really not the primaries that are different. The Infitec filters and glasses are narrow band color filters (simplifying things a bit). You can use it without a color correction box as a working home brew but some colors are affected quite a bit. You can do this by purchasing two pairs of Infitec glasses, and using one for the projector filters and one for viewing. Search for the thread where one AVS member has done this. He said only certain colors are truly bothersome. You will need to use two projectors with the associate signal splitting issues. Not for prime time. The color correction box I think is available from the US Infitec importer at about $6K but its obtainment is sort of back door. They really don`t deal with consumers just commercial. They have the glasses too. My guess is that Dolby, Barco and Sim2 and the importer are exclusive licensees with only Sim2, Dolby, and Barco allowed to incorporate it in projectors. This is how Sim2 likes to operate, getting a big jump on say 3 chip DLP by TI making the chips available to them through Delta more or less exclusively for some period of time. All this might not be exactly how it works but it is close enough for discussion purposes. The Sim2 pair of Lumis modified for high output and consequent lower on off makes the expensive system mot that great for 2D. I expect for around $80K MSRP discounted to whatever street, they will not sell many, a Barco or DPI using shutter glasses being a better and more economical option considering 2D performance which will remain for most the primary viewing option..

My prior setup was infitec using glasses lenses for filters, and the separation is simply amazing. Unfortunately I was never successful in getting the color correction satisfactory. Even with the combined corrections of the projector and my pc, the range simply wasn't enough.

Then perhaps I misunderstand what "primaries" are.

I looked into this a while ago along the same lines as the OP and there are solid state lasers available at 593/635nm (R1/R2) 515/543nm (G1/G2) and 447/473nm (B1/B2) which would get through the Infitec filters which have "holes" at 580-630 and 630-760 for R, 500-530 and 530-560 for G and 440-460 and 460-475 for B. Is using a red laser (or very narrow bandpass filter) at 593 and one at 635 not considered "different primaries"?

The two different Infitec filters I believe and God knows I don`t really understand all this, are placed in commercial projectors after the Xenon bulb but before the chips. They rotate quicly like fan blades and then What? The light passes through a prism and then to the three chips, the light right eye signal is synced to the two different rotating filters and the eye glasses with the same filters, a different one for each eye, prevent cross talk. In a two projector solution I believe but for all I know I am wrong, the filters are placed in front of the lenses, one for each projector, a left eye one and a right eye one. In this application, the whole spectrum is beig filtered, after combination of the primaries. So I really don`t know what the reference to diferent primaries is about in a 2 projector consumer solution but of course I could be wrong. So maybe someone can jump in and unbend me out. Thanks

So that would appear to be a consumer version of an active (rotating fan blade) Infitec system. And the MSRP? An exspensive Barco in the what $110K range plus the active filter and correction source box and glasses. I am guessing something like $135K.

Mark, I agree it is close to magic but here's a link to a picture of the transmission spectra of the two filters showing the left eye and right eye get different colors for the R G and Bs.



The Xenon (or whatever) source gets filtered by one filter to provide only 629nm for red while the other filter gives only 615 nm (a different colour), then the same thing for G (532 nm and 518 nm) and B etc.

$6K for the CMS box along with two "cheap" projectors (pair of RS1s or 2s) and a pair of glasses (a cheap option) for the projectors and glasses for viewers gets you there (with your existing screen) while a "proper" i.e. flat pair of filters for the projectors might be $$ but well short of $135K. I'm curious how it all would turn out.

In the two projector solution, can the filter be placed after the lens?

If one wanted a passive stereo solution, it would be much less expensive to use circular polarized filters & glasses with two inexpensive projectors that didn't have any polarizing internally.

But you are still stuck with the silver screen.

Yes, but the lens throw needs to be greater than 1.7:1. See attached PDF.

 

INFITEC filter mounting outside.pdf 37.4765625k . file

Thanks. That should not be a problem in my case but the question is how well the system works meeting that requirement. I assume the longer the throw, the better.

What "box" are you going to use for color correction? It isn't just a case of two projectors and two filters like it is with a polarized 2 PJ system.

There is a color correction box available from the commercial distributor. It has to correct each projector differently of course because the filters are different on each. The box also syncs the filter blades on a single projector Infitec projector to the alternating particular eye signal. I know. I am simplifying. The Sim2 two projector model includes a box to correct the colors.

Isn't the price of that box something like $6000?

Yes. I have posted that several times before and one needs the box and at least two pairs of glasses, one to take a part for the filters. Nice flat filters can be purchased too for more $$. So one could do this system with two cheap projectors for under $10K. I am not saying do it, I am saying it can be done. Remember this system eats light. IT EATS 93% of the light.

The odds that two cheap projectors of the same model haveomg lens that are close to being identical is slim so the alignment of the two projectors images to be on top of each other is extreamly slim.

They don't have to be "perfectly" aligned (the way they would if you were simply light doubling for 2D) - slight shifts sideways would move the main flat plane a little back and forth, while a vertical displacement of one or the other might be more of an eyestrain. SLight differences in optical distortion (barrel, pincushion etc) between the two might produce some interesting 3D distortions but they'd have to be pretty gross to make a big difference.

Hello everybody,

I have built a dual front projector setup that may be of some interest for some of you who cannot afford 10 K$ (I cant either).

I am using 2x sony's fullHD VPL-HW15 and Dolby filters/glasses. I have both infitec and dolby glasses and I found the Dolbys need much less color correction than the infitecs, still keeping excellent crosstalk characteristics. I am using a pair of glasses lenses as filters for the projectors. The lenses are wide enough to let the full beam go through. No edge blocking.



The lenses from the dolby glasses are curved and match a throwing angle of about 20°. As the filters work best when perperdicular to the light path, medium throw projectors should fit perfectly. My own setup is short throw so I am getting slight ghosting at the edges and the corners. Nothing I can't live with. The ghosting is still better than the one I got with my linear polarized filters and Harkness silver screen I had a very hard time with: http://www.avsforum.com/avs-vb/showt...8#post18692288

As you know, this technology needs color correction. The source is a HTPC. I was not able to fulfill this requirement with the normal graphic card settings and/or the projector's. So I built a color correction of my own, using directshow filters and AVIsynth. DirectShow filter is RGB3Dlut: http://bengal.missouri.edu/~kes25c/ddcc.zip

The idea is to convert colors using something like:
http://www.jumbovision.com.au/files/...hite_Paper.pdf

R' = a11 R + a12 G + a13 B
G' = a21 R + a22 G + a23 B
B' = a31 R + a32 G + a33 B

As I do not have any optical equipment to get the correct parameters, I simply used a visual estimation with my own eyes and Photoshop. I am very pleased with the results, this correction seems to be enough, at least to me. No eye rivalry any longer. Red is a little orangy though.

A simple program to build the two lookup tables used by RGB3Dlut:
----------------------------------------------------------------------------------------------
#include
int r,g,b;
int R1,B1,G1;
int R2,B2,G2;
FILE *table1,*table2;
main()
{
table1=fopen("D:\\TABLE1.BIN","wb"); table2=fopen("D:\\TABLE2.BIN","wb");
for(g=0;g<256;++g){
for(b=0;b<256;++b){
for(r=0;r<256;++r){

/* RIGHT eye (allow 10% clipping on green) */
R1 = r*0.72;
B1 = b*0.81;
G1 = 1.1*g; if(G1>255)G1=255;

/* LEFT eye */
R2 = r*0.9;
G2 = g*0.56 + r*0.33;
B2 = b*0.72 + g*0.1;

fwrite(&B1,1,1,table1); fwrite(&G1,1,1,table1); fwrite(&R1,1,1,table1);
fwrite(&B2,1,1,table2); fwrite(&G2,1,1,table2); fwrite(&R2,1,1,table2);
}
}
}

fclose(table1); fclose(table2);
}
----------------------------------------------------------------------------------------------
Then the AVIsynth script that takes a side-by-side 2x720p movie for example:
----------------------------------------------------------------------------------------------
LoadPlugin("C:\\Program Files\\AviSynth 2.5\\plugins\\ddcc.dll")
video=DirectShowSource("D:\\movie.mkv").converttoRGB()

R = video.crop(0,0,1280,0)
L = video.crop(1280,0,0,0)

R = R.rgb3dlut("D:\\TABLE1.BIN")
L = L.rgb3dlut("D:\\TABLE2.BIN")

stackhorizontal(R,L)
----------------------------------------------------------------------------------------------
If you have a powerfull enough PC, you just play the AVS file on the fly with your favorite player. If you get judder, audio synch issues, you have to reencode the movie. My HTPC (dualcore AMD 4850e) was powerfull enough to play a 1.35:1 - 2x720p AVS file but not enough for a 1.78:1 - 2x720p.

The above match my projectors technology: UHP lamp and LCOS (sXRD) panels. The parameters may work with other brands of projectors as long as they use UHP lamps.

The brightness is surprisingly very high with my two 1000 ANSI lumen projectors along with my 2 meter wide screen. I could even use the lamps in eco mode! But full power is great.

I hope this may be of some help.

EDIT: Much better correction now:
http://www.mtbs3d.com/phpbb/viewtopi...980c5&start=32

Jack

Hello Jack,

An interesting method you're using there, I'm thinking of buying a second JVC RS1 and do it the same way.

I still have a few questions about how it works:

1. Where can you buy / find Dolby 3D glasses ?

2. Does it work if you just connect a PS3 (for BluRay movies) to your receiver that has 2 HDMI outputs and then give the same videostream to each projector and just align them a bit from each other or do you need special 3D software to split the videostream into 2 separate ones ?

3. Are the lenses from the glasses made out of plastic or glass (melting problems) ?

Many thanks, Kevin.

1. Dolby glasses are only sold to professionals. They do not sell to individuals. Still I had the luck to convince a French reseller to sell to me. I just got the glasses last week.

You can try one of these: http://www.dolby.com/uploadedFiles/A...ribListWEB.pdf

2. Projectors cannot read the same image. It must be split. Left image to P1, right image to P2.

I am using a HTPC. I know nothing about PS3. The movie is played side-by-side and the graphic card is in the horizontal span mode, using two DVI outputs. So splitting is easy. Color correction is done by software, as I explained. The upcoming 3D blurays will be hopefully read by PowerDVD 10.

Still I cannot use my projectors' fullHD capabilities as the graphic card wont output 2x1080p@24fps in span mode. So next week I am getting a Matrox's digital triplehead2Go. See if it can do better.

Tip: If you can output side-by-side image from your PS3 and use this triplehead for the splitting, this might work. Not sure though... In any case, you wont be able to apply color correction.

3. The lenses from the glasses are glass. No worry about melting them. They are directly on the projector lens.

Jack

It is a easy fix to use Aluminum Rustoleum Paint form Home Depot to do the Silver Screen. I use it for my theater and it works great!! It keeps the Polorization with no Ghosting. Don't get ripped off on the screens. Be a little creative.

I've heard this paint cures over time and loses polarization. How long ago did you paint your screen?

And how's the hotspotting?

Do you have another thread where you've shared your technique and results? If not, you should jump over here: http://www.avsforum.com/avs-vb/showthread.php?t=1154909

And now back to waiting for an affordable Dolby/Infitec/Interference 3D DLP Projector.