| Author | Message | ||
     Patrick Rating: N/A |
I've been doing some research on stereo projection systems and I have a couple of questions about the problems with using LCD projectors. Polarized systems don't work with LCD projectors because somewhere in the projector optics the light is already polarized. Is this in the LCD pannel itself or in the accompaning optics? Shutter glass sytems don't work with LCD projectors because they are too slow. What part of the system is too slow? One thought I had was that most LCD projectors are locked a 60Hz. This means that each eye gets the equivilant of 30Hz and this is too slow. The only other meaning I could think of for too slow was that the LCD pixels fade too slow after being strobed and therefore are very ghosted. The reason I'm curious about this is that I've found that it is possible to build a homemade LCD projector. I am trying to figure out if I can overcome some of the problems that LCD systems have with stereo projection. -Patrick | ||
| Giorgio Bogoni Rating: N/A |
The LCD panels itself is polarized but you can take advantage of this just rotating the polarization of one of them. Pay attention that some projectors use 3 panels (RGB) with different polarization angles. About the fact they are too slow for active stereo, I still think so but someone say it's not always true. Giorgio. | ||
| Patrick Rating: N/A |
Thanks for the reply. | ||
| OliverRedfox Rating: N/A |
The reason lcds are too slow isn't because of the 60hz value. It's because the lcds still glow slightly even after the power has hit them. With shutter glasses, you get instant ghosting because as the new frame is being drawn, the old frame is still partly visable. It's nice in the fact that it keeps lcds from flickering when veiwed normal, but it stops shutter glasses from working with them. Some lcds can fade the pixels faster then others and don't have the ghosting problem but I'm not certain which ones can handle it. With my projector, I use red and blue glass with it. It took a while for me to get the color settings right on my system but it works pretty well. I lose details when viewing (same thing happens with tvs) but 3d effect is amazing on a 100" screen. It works great with driving games, but for shooting games, it's hard to make out people in the background. Good-luck with your homebrew system. | ||
| wboyce Rating: N/A |
I have recently purchased The Ultimate 3D Collection on DVD, which included a 3D converter box and 2 shutter glasses (I think IO Display Systems 3D glasses (wired)). This has a button to reverse the shutter glasses. I brought a Sony Cineza VPL-HS1 LCD projector and the 3D does work, not brilliantly. But good enough for me. I watched the Haunted Castle DVD and the flicker was not noticeable. I projected to a screen approx 100" diagonally. I hope this helps you. | ||
| dragoncarver Rating: N/A |
Yes yes yes 150" LCD Sony VLP(????)11-HT That is my unit. "shutter glasses won't work on them" I had a hard time believing it! I have tried all the settings in my machine but nothing worked. Being the obsessive person that I am I had to keep looking. My serching had led me here. I cruised through looking for somwe insight. Some guy VR... somthing or other. Had a great idea. Here it is in a nut shell; You will need a DVD player that will send the picuter singnal in a format I believe is called progressive. (the setting that works on mine is called animation) . A second signal that comes from anouther unit and feeds the glasses. This sounds CRAZZZZY !! I was despirate to try anything ! My LCD was set to using only the front bank and to scan progressivly. My first exparimments with this Idea gave mixed results. My glasses where fed off a VHS with anouther 3-D tape in it. I would get good synconization for abount 5-10 minutes. Then the signal would fade. I assume that the VHS is not harmoniuse with the DVD. My second expariment will feed the glasses with anouther DVD source. hopefully the singal will not degrade. chances are thwy will be syncronus but 90* out of ballance. Thanks to VR for the basic idea. | ||
| Christoph Bungert (Admin) Rating: N/A |
#### You will need a DVD player that will send the picuter singnal in a format I believe is called progressive. You can't have progressive and 3D at the same time. The whole idea of field-sequential 3D-DVD's is that the 3D-information is put into the odd and even fields of an interlaced-coded MPEG2 stream. Using a progressive scan DVD-player is definetely destroying the stereo information. Christoph | ||
| Anonymous Rating: N/A |
I own a sony VLP-CS1 (LCD projector). There's no way to make it work for active stereo. The LCD panels are too slow. I cannot understand what you are doing ... why two signals? Why can't you duplicate one signal using a common Y connection for video RCA cable? What's the great idea? | ||
| dragoncarver Rating: N/A |
I don't know enough to explain why this works It was a hunch played out some where else in this site by a guy named VRJUNKIE . This hair brained idea I think comes from this idea. what ever the signal is coming into the LCD there is a small delay from the point of input to the point of output. the processor in the glasses has no noticable delay and flickers at a rate ofset from the LCD projector. This is my thought I maybe totaly wrong but I believe that if you could adjust the delay timing in the shutter glasses the same signal could be used for the glasses as well the projector. All you engineers who have all the reasons why this won't work should have the imagination enough to find a way to make it work. I love the feed back that helps... Let me stress I don't know exactly what I'm talking about. I AM EXPERIMENTING !!! My system is HDTV capable I will tell you more if you would like. | ||
| dragoncarver Rating: N/A |
does the screen print picture , right picture, left, right,....... and the glasses flash left eye right eye >? then the TV must setup one scan left one scan right. Is that routine 60 times a second 30/30 ? dragoncarver@aol.com | ||
| wboyce Rating: N/A |
I am running the following Sony Cineza VPL-HS1 Pioneer DVD DV-533K The Ultimate 3D Collection (comes with shutter glasses and 3 IMAX movies). And believe me, I get 3D. On a 70" x 70" screen and sitting about 3 metres from the screen, images project out about 2 metres and in about 2 metres. The flicker is not that noticeable. One thing I did find is that you need to reverse the shutter glasses. There is a button on my 3D television box (box shutter glasses are connected to), that allows you to reverse. I discovered that the 3D worked by wearing the glasses upside down (then tried the button). I was told that this would not work, but it does. As to the refresh rates on LCD projectors, they are getting faster every day. The Sony Cineza is not the fastest, but it is capable of 92 Hz. When I was looking Sanyo had LCD projectors that could go as fast as 120 Hz. If you are playing back 3D DVD movies then 60 Hz is all that is required. When I am watching the 3D IMAX movies the Sony Cineza is only running in 60 Hz. Hope this helps. | ||
| wboyce Rating: N/A |
Do what I did, try before you buy. The 3D television box, can be powered by a 9V battery (I used NiMH 150mAh 8.4V rechargeable). Take the shutter glasses, 3D television box, IMAX 3D movie and battery into the store selling the video projector and try it. Also try with the glasses upside down as well. The Sony Cineza VPL-HS1, is a new LCD projector, only released November 2001, I think. It is relatively cheap RRP $2995 US, $5995 Aus. You should be able to get a better deal than RRP. Lots of stores have them. This is the best advice I can give. | ||
| wboyce Rating: N/A |
I also use the RCA video out to the 3D Television Box, but use the S-Video cable from the DVD player to the Video Projector. It gave better results. | ||
| FrancoT Rating: N/A |
Hi all, anyone has tried active stereo using the projector NEC 150Z? It's a DLP projector with the new DMD (Digital Micromirror Device) tecnology. It basically means that it should be able to reach true 120Hz of refresh. Stereographics is claiming that this tecnology works on the Christie Digital Systems Mirage projector series, so it might work also on the much cheaper NEC. What do you think? Franco | ||
| Anonymous Rating: N/A |
I am running two LCD projectors with Cyviz stereo converter at a silverscreen. Great solution - no flickering. See www.cyviz.com for more information | ||
| M.H. Rating: N/A |
Franco: Christe product is specialy optimized for stereo. It gives exactly one frame delay during the internal image procesing. You will have trouble to sync to standard DLP projector .. Anon: The cyviz solution is obsolate. Dual output graphic card with proper software can give beter result for beter price .. | ||
| Alexander Oest Rating: N/A |
Franco, I searched for some specs on the NEC LT150z, but all I found was a post in avsforum saying that: ""Full Panel" or native resolution on an LT150z (or LT150 or VT540) is always 1024X768. Any other video mode except 1024X768@43-85Hz refresh represents a non-native resolution that invokes the internal projector scaling circuitry which scales the incoming mode to 1024X768@60Hz." Sounds like it can do 85 Hz native, which might be acceptable. At least better than 60 Hz. Where did you get the impression, that it could do 120 Hz native? Alex | ||
| Franco T Rating: N/A |
Alexander, you are right. 85 Hz is the maximum you can get out of a LT150z and I was tricked by some inaccurate specs I found floating on the net. But in the meanwhile I've also found a very new Sharp projector (presented at last Cebit) that really sounds intriguing. Have a look: http://www.sharp-usa.com/products/ModelLanding/0,1058,780,00.html They claim a 3X speed weel and refresh rate up to 200Hz (and 70x3 is about 200Hz... what a coincidence) Is this the first consumer-level DLP able to go stereo? Franco | ||
| Alexander Oest Rating: N/A |
Franco I agree, the Sharp PG-M20X looks promising. I've emailed the Swedish Sharp office (covers all nordic countries) and asked if it supports these refresh rates without some sort of conversion. If they email me back, I'll keep you posted. Alex | ||
| M.H. Rating: N/A |
Alex: I have E-mailed so Sharp USA as well. No response up to now. The key parameters witch we need to know: No frame reprocesing - working on identical frequence as input. No or one frame delay - or we will be forced to use some sync. time shift correction circuit. | ||
| Anonymous Rating: N/A |
Tried the realtime chat, + is me, - is Sharp dude, here are the details. -How may I assist you? +Got questions about PG-M20X -What types of questions? +The thing is that I'm looking for a projector that is suitable for stereoscopic viewing +3D Glasses +so I need to know if I run say 800*600*120Hz from a PC, does it display each frame EXACTLY as the PC spits them out (max 1 frame delay)? -I am not certain. -I would suggest calling our tech support at 1-888-467-4277, option2. +Got a european number? -Let me check, one moment. +thnx -I am sorry, but we do not have a European number. +so how can I find it? -I am checking to see if it is located on our International website. +Found it, http://www.sharp-eu.com/nav/frames/sub_frame.htm +thanx for the help The last page has links to pages for most EU countries, I'm calling tech support in my country tomorrow. Help out and ask in your countries to, tech supports usually know a lot or jack shit, so several sources are good to have. | ||
| M.H. Rating: N/A |
The best way will be probably to borow and try a model. The eventual nessesery phase shift (it means frame time delay of the projection) could be corrected - I gived orders to one of the electronic specialists on out Univ. to built such device (we will use it to sync to 100 Hz tV in addition). If it will work it will be realy the best stereo projection solution - no ghosting, hi frequnce, hi brightnes, non deploariazating screen not nessesery, easy communication with one PC with HW page flipping output. I have got information from pople testing the Christie Digital Mirage projector that it gives absolutly superiot stereo, I hope Sharp projector can do the same cheaper ... | ||
| ItsikW Rating: N/A |
Patrick: I have recently constructed a passive stereo display system using two LCD projectors. I am taking advantage of the native polarizations to achieve nearly 100% optical efficiency. This is along Giorgio's comment. M.H.: Can you give more details on the software that makes CYVIZ obsolete? ItsikW | ||
| Patrick Rating: N/A |
ItsikW: That's very cool about the passive stereo display system. Did you just put one of the projectors on it's side or did you reorient the polarizers on the lcd itself? | ||
| M.H. Rating: N/A |
Ptrick: The ligt from LCD projector is not properly polarized (different ploarization for different colors). It is nessesery to put a polarized filter befor each projector ... Thry to search for Andrew Woods article with complet explanation ... | ||
| Alexander Oest Rating: N/A |
Hi All Any news on the Sharp PG-M20X or other stereo-capable projectors yet? I've tried emailing Sharp's office in Sweden (there isn't a Danish one), but they haven't replied. It's been weeks now. Today I asked at dlp.com if they could recommend a suitable projector. Maybe they'll answer. I don't count on it, though. Still searching Alex | ||
| Thomas Rating: N/A |
M.H.: Please give some more details about your statement: 'The cyviz solution is obsolate' I'm really interested in your opinion Krokus | ||
| M.H. Rating: N/A |
Cyviz solution is obsolate becouse: 1) It could be replaced by dual output graphic cards 2) It degradate the signal by analog data redigitalization and reprocesing 3) It is overpriced If anybody does not agree, let me know , please, some example of a situation in with you realy need CyViz ...( I know one, obtaining signal for 4 projector large passive stero panormatic projection for dual output graphic card, but this is relay a bit non-usual situation) .. I know about the dual card output genlocking problems, but it is not so critical for passive polarized projection (people using it do not report problems) ... | ||
| Franco T Rating: N/A |
Hi all, still on the Sharp PG-M20X issue. I've just found a review of the unit at projectorcentral. They don't mention anything 3D related but this bit looks interesting. I really think that someone should try this projector... Franco "Sharp built the PG-M20X for the mobile presentation market. Accordingly it is compact and light (5.8 lbs), and designed to pump out a bright 1900 ANSI lumens. It uses a standard 4:3 format XGA resolution (1024x768) DLP chip, and doesn't have quite the connectivity you'd like. It also has on-board audio, which is useless. Typical commercial mobile projector, right? Wrong. Look a bit closer and you find that the PG-M20X features the new Double Data Rate DLP chip with 12 degree mirrors as well as a 3x speed color wheel. This light engine produces a smoother, higher contrast (1000:1) picture than earlier generation DLP-based products. It virtually eliminates the rainbow effect and flicker issues that have plagued some DLP users in the past. That by itself is a MAJOR step forward. Add to that some advanced deinterlacing and scaling capability, and suddenly you have the makings of a first rate home theater projector." | ||
| ItsikW Rating: N/A |
Franco, The meaning of the description you cited is simply that this projector uses the new generation 0.7" DMD chip. There is nothing spectacular in this: all new DLP projectors use the same chip, simply because the older 0.9" chip was discontinued. TI increased the mirror deflection angle to 12 degrees (from 10) to compensate for the reduction in optical throughput that comes with the chip size reduction. The double data rate is an attribute of the chipset that drives the DMD. It improves the image quality, but has nothing to do with refresh rate. To my best knowledge, single-chip DLP projectors are stuck at 60Hz, and will remain so in the near future at least. To some up, the new features associated with the new 0.7" DMD chip are irrelevant to stereoscopic projection. Itsik | ||
| Franco Rating: N/A |
Hi Itsik, thanks for the precious infos. To be onest I was more intrigued by the "3x speed color weel" spec. Do you have any comment on this? Franco | ||
| ItsikW Rating: N/A |
Franco, I overlooked the "3x" detail. This probably means that the color wheel makes three revolutions per frame. As far as I know, DLP projectors use normally "2x" color wheel, namely, two revolutions per frame. Increase in number of revolutions per frame indeed reduces the rainbow effect and also the flicker. However, this has no impact on frame refresh rate or stereoscopic projection prospects. I have a feeling that we are drifting away from this discussion topic... Itsik | ||
| richardw Rating: N/A |
I bought a Sharp PG-M20X about a week ago.. and first thing I did was try the 3D stereoscopic test... I first tried the projector at 1024X768 60Hz.. I thought it was working.. it looked amazing... 3D looked great.. then it slowly started drifting in and out one eye would drift between red and greenish tints.. and every once in a while the eye order would switch and I would have to toggle it on my shutter glasses control box.. I then tried different Hz rates... everything from 60Hz-200Hz and nothing seemed to fix the problem.. I then tried different resolution as well... nothing.. it would always drift in and out of sync... but when it did sync up for those few seconds.. it looked incredible! I'm using a dual PIII 1Ghz system, Geforce 3 with the 30.82 drivers, and the vrjoy2000 glasses - http://www.vrstandard.com/products/vrjoy2000.htm if anyone has any ideas how to fine tune the projector to keep it in sync then this would make a great 3D projector... also I didnt try the interlaced method yet that might work... I was more interested in the page flipping mode.. | ||
| Anonymous Rating: N/A |
somebody know where i can get a proyector model that supports 70,85 or 90 hz withouth reprocess the signal or frames,to use in a 3d page flipping projection system. Can anybody tell me if Sony Cineza Projector with a PC suppors more than 60 hz? thanks Thanks | ||
| Anonymous Rating: N/A |
Somebody knows where I can get a projector model that supports 70,85 o 95 hz without reprocess the signal or frames,I intend to use it in a 3d page flippin projection system.Can anybody tell me if Sony Cineza Projector with a PC suppors more than 60 hz? thanks | ||
| Anonymous Rating: N/A |
Can you give me your opninons about the Barco Cine 7 and Cine 8, and what about the D-ILA tachnology from JVC, on their sites they post a 100Hz for JVc and up to Horizontal 15-69 kHz Vertical 37-210 Hz (autolock) for the Cine 7 CRT projectors: http://www.barco.com/projection_systems/products/product_specs.asp?element=333 Somebody knows the price for the Cine 7 and 8, and where can you get it for a low price?. Thank you. JB | ||
| Alexander Oest Rating: N/A |
richardw, I had the exact same problem when I tried the Optoma EP755 projector. I didn't find out how to solve it. If it was possible - either by software or some circuit - to adjust the sync of the shutterglasses, I guess it would solve the problem. Btw, the Davis DL x10 works fine in 60 Hz due to its option of keeping native refresh in 60 Hz only. I think it's called movie mode or something like that. If you have such an option on your Sharp, it might do the trick. Alex | ||
| ItsikW Rating: N/A |
richardw, I know your Sharp has a clock adjustment. It is under 'Fine Sync' menu. Maybe you can try it. However, I am afraid that nothing will help; LCD projectors seem to have an internal refesh rate clock, which is not synchronized to the signal. I have tried page flipping on my Eiki LC-XM2. At 70Hz refresh rate I saw a periodic phenomenon at a frequency of 1Hz approximately. At the beginning of the period the two views were separated. Then they started drifting, and after a second the separation seemed to disappear. Then suddenly the separation re-appeared, and the cycle started again. This is certainly a beat between an internal clock in the projector and the signal. ItsikW | ||
| oboude Rating: N/A |
I make a test today with a Epson powerlite 50C, ìn page flipping mode, with the Nvidia driver, I have a one TNT2, what I see in 640X480X16X70 or 800X600X16X70 or 1024X768X16X70 is that I can see tha images in 3D, but every 3 o 4 second, I see a new sweeping it`s looks like a refresh line, that come, from the top, to the end of the projection. The best results I obtained them with a 800X600X16X70 resolution. If anybody have any Idea, pls tell me .. Oscar Boude | ||
| Anonymous Rating: N/A |
I know that for their physical properties, the DLP technology is best suited for polarizing applications, but apart from DLP, what is the best option for 2 projectors with polarizing filters to a silver screen?: JVC DLA technology? Sanyo LCD's? If you have a rating of 1000 lumens, how many light you are going to get after the polarizers? Where can I get the polarizing (Glass or film) filters?, Thank you. | ||
| ItsikW Rating: N/A |
Anonymous, You can use LCD projectors with polarizers for passive stereo display. However, you have to align the polarizers at +/- 45 deg. You will loose 50% of the light. Alternatively, you can use half-wavelength retarders to rotate the polarization by 45 deg without loosing any light. Sheet polarizers can be bought from Edmund Sceintific. Itsik | ||
| Anonymous Rating: N/A |
how well do these half-wavelength retarders work? is it just like polarisers but witout the light loss? what do they cost? where can I buy them | ||
| ItsikW Rating: N/A |
Anonymous, I have a projection display with retarders, and it works quite well. See more explanation on the subject under the topic "A cost-effective passive stereo system" Itsik | ||
| Anonymous Rating: N/A |
Dear Friends, The requirement for working with the retarders is that the LCD projector must be polarized in one direction. Do you know any such a LCD projector avalable now? The old model of LCD projector with one LCD panel is generally not bright enough? Thanks | ||
| Anonymous Rating: N/A |
I have an Infocus X1 DLP projector and Elsa Revelators. Has anyone had any luck getting a similar setup to work with games? The revelators used to work fine but I haven't pursued since upgrading my video card - geforce3 ti500. I have recently upgraded to geforce4 t14200. I don't have 3d video shutter glasses, just the revs. Any help on how to proceed would be great. I have some wedding photos in 3d I'd like ot look at in 3d again, not to mention in LIFESIZE! WOW! Please help.. | ||
| Dr Brian Rating: N/A |
Where can you buy a half-wavelength retarder? Will it work with a Sony Cineza LCD projector? | ||
| Anonymous Rating: N/A |
Finding your websight was like finding a needle in a haystack. |
