Hardware options for Stereoscopic Visualisation

The main components of a stereo 3d projection system are dependant on the type of system that you choose:

 

1) Active Stereo 

2) Passive Stereo 

3) Auto Stereo

 

There is also a Hardware Links section below.

 

A 2005 UCL presentation on the various technologies can be found here :

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1) Active Stereo:

Active Stereo with active Glasses:

For education the cost of active stereo glasses and the requirement to use more expensive "Quad Buffered" Graphics cards probably means this is not the preferred choice where groups of more than 3 or 4 will use the system at the same time.... and these days it is arguable that the perfomance and comfort of passive systems are as good if not better. On the other hand an active system just has one projector and uses a standard screen surface, so if the glasses become more affordable and sturdier then this could become an option... many current DLP's will run frame sequential stereo but not at full 60hz per channel. There is information and a list of standard DLP's capable of active/time sequential stereo here :

 

http://www.cmst.curtin.edu.au/publicat/2007-05.pdf

http://www.3dmovielist.com/projectors.html

 

The new F10 AS3D active projector from Projection Design is the first of a new option

 

Full 120hz refresh, and accepts two DVI/VGA inputs from a standard graphics card.... so will convert your standard side x side passive stereo set up to active. This could be really great for systems with only 5 - 10 adult users at a time, as the cost of the active glasses, around £100 each, and a tendency to break easily probably rules out systems with a larger audience or with children.

http://www.projectiondesign.com/Default.asp?CatID=1691 

 

Active Glasses Database 24/9/09 : Download List

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Active Stereo projector with active to passive filter allowing use of passive glasses.

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2) Passive stereo using polarised glasses and filters:

 

There are different forms of passive stereo, most people are familiar with Anaglyphic, usually using Red/Green glasses but this impairs colour and is not comfortable for prolonged use - so I don't recommend this. Much better are systems using polarising filters, there are usually two projectors, one for each "eye", which will be aligned on screen using a stacker and will have either linear or circular polarising filters in front of each of the lenses and the users wear matching polarised glasses. Choice of filters and screen surface will affect the amount of ghosting/cross talk you will see. However, with a well matched system ghosting should be hardly noticeable.

 

Screen

I have tested the majority of "3D" screen materials and while they do all work, some are much better than others. Image brightness, colour rendition and the amount of ghosting (crosstalk) is all affected by the choice of screen and screen/filter/projector combination.

 

Projectors

In my opinion DLP projectors are usually best for stereo, as they usually have a higher contrast ratio, better blacks and standard polarising filters will work. However, there are many installations around the world that use LCD's - be careful though, many LCD projectors will not work with standard filters as the light source is already polarised and poor contrast ratios can lead to your blacks being mid-grey!

 

Stacker and Filter holders

The aim here is to be able to easily align the two projectors, this usually entails stacking the projectors on top of one another and then using the mechanical alignment features of the stacker. However, my favourite projector had a feature called 3D reform, which allowed digital alignment, making it really fast to set up... unfortunately the DLP version of these projectors has now been discontinued - we will be testing the LCD version soon :-) The requirements also vary depending on whether it is a fixed system or a portable system.

 

Computer

The are many possible choices here - you can choose Windows, Linux or Mac and there are applications which will work in stereo on all of these platforms. However, as a Mac user myself, I believe the new Mac Pro has a big advantage over the others, in that it is capable of running all three operating systems.... so you don't have to compromise. The most important element to get right when specifying your machine is the graphics card- this is where most of the work is done and having the fastest card with most memory that you can afford is going give you the best performance. However, you don't need to go for the expensive Nvidia Quadra cards which are advertised as having "stereo in a window" unless your application requires "Quad Buffered" mode to run.... and if it does you will also need an active to passive convertor or use active stereo - see above.

 

Apple Mac Pro : Suggested Minimum Specifications

 

Processors : Two 2.8 GHz Quad-Core Intel Xeon

RAM : 2GB is really the minimum requirement and more memory will improve performance, and with some applications also increase the size of dataset that can be handled and reduce loading times. 4 GB is usually fine. Only order the base requirement from Apple and get your additional RAM from a good third party like Crucial.

Graphics Card : Nvidia GeForce 8800 GT 512MB (2 x dual-link DVI) or if money is no problem the Nvidia Quadra FX 5600 has 1.5GB of video memory.

Hard Disks : up to four : 500GB 7200-rpm Serial ATA 3Gb/s. Larger Disks are now available.

Optical Drives : one or two : 16x SuperDrives

Both Bluetooth 2.0+EDR and AirPort Extreme

 

Filters

These can vary in price dramatically, for systems using DLP projectors up to 2,500lms, we have found that cheap Cokin filters are as good as any, if used with the SilverFabric screen (below). It is important to match your filters to your screen fabric to minimise ghosting.

 

Glasses

American Paper Optics are still the best source for both paper and robust plastic theme park style glasses. They also do more expensive Aviator glasses which are to be recommended for prolonged use.

 

Audio System

This is down to preference and type of use.... but good audio is essential where you are trying to create a completely immersive experience.

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3) Auto Stereo:

This is stereoscopic visualisation without glasses, and is where a lot of development is currently happening. All of the major LCD screen manufacturers have screens either available now or in development. There are some that are almost affordable (£1,000 -£1,500) but screen sizes are usually below 19" and others tend to be expensive... but of course with time this will change and as gamers start to buy the screens...

 

Great for individual use and in situations like libraries, but are not yet a replacement for large scale visualisation and the benefits that it can bring.

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Hardware Links :

 

Filters

 

Beware of acrylic or film type filters these don't tend to last and can be affected by heat from the lamp either melting or depolarising.... Glass filters tend to last longer. Also think how you are going mount and adjust the filters, this makes the difference between good stereo effect and headaches due to loads of ghosting. For this reason we have tended to use round filters that can be rotated to obtain the best exclussion.

 

American Paper Optics :

Have a range of both acrylic and glass filters and up to fairly large sizes to order. I don't think they are listed on their web site ... but ask for Craig Jones :-)

direct telephone:     +1-303-399-8889

direct fax:               +1-303-399-8881

website:  www.3dglassesonline.com

or email him at : >Dshades3d at aol.com   but first removing spaces and replacing the at with the @ symbol.  

 

Cokin :

Cokin A series Linear Polarised :

 

We use these on our NEC LT265 and LT245 based travelling systems along with our SilverFabric demountable screens. However they are not great with ourDaLite screen and for this we use our Christie (B+W) Filters.

 

List of online stores

http://www.intro2020.co.uk/pages/online.php?product=COKIN

 

Awater3D :

They offer a range of filters and specific filters for use with both DLP and LCD projectors.

http://www.awater3d.com/en/3d-stereo-polarizers/

 

Screen Tech Filters :

 

http://www.webmart.de/wmshop.cfm?ID=44918&ProductID=416351&CID=71168&do=detail

http://www.webmart.de/wmshop.cfm?ID=44918&ProductID=357690&CID=71168&do=detail

 

Lee Filters :

The Lee filter system is not cheap, but it is very flexible and by using the right combination of holders and filters it can make your life just a little easier. Do watch though, we have found that they are very heat sensitive and need to be mounted further from the lens than other glass filters we have used.

 

http://www.leefilters.com/camera/products/range/ref:I46C9C1B6AA3DD/

http://www.morco.uk.com/latest/leepol.htm

 

B+W Filters :

Again not cheap, but we have found the B+W filters do give good exclusion (less ghosting) with some of the cheaper screen materials.

 

http://www.schneiderkreuznach.com/pdf/filter/bw_filter_programm_e.pdf

http://www.daymen.co.uk/

 

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Glasses

 

>American Paper Optics are still the best source for both paper and robust plastic theme park style glasses. They also do more expensive Aviator glasses which are to be recommended for prolonged use.

 

http://www.3dglassesonline.com/

 

http://www.the3dmarket.com/Plastic/lin_pol_theme.asp

 

http://www.the3dmarket.com/Plastic/lin_pol_aviation.asp

 

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Mirrors

 

Where you want to shorten the distance from screen to projector you can introduce a front silvered mirror in the light path. Often used with rear projection systems.

 

http://www.screen-tech.de/Mirror.html

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Projector Mounts

 

Chief - Stackers

 

http://www.chiefmfg.com/search_results.aspx?CategoryID=20

 

Use the LCD2c for ceiling mounting along with the appropriate projector RPA and the LSB100.

 

http://www.chiefmfg.com/productdetail.aspx?MountID=122

 

>Since Chief has discontinued its range of ASU slide projector table top stackers that were perfect for the job of aligning two small DLP projectors,  the LCD2TS is now the only option for table mounting, use along with the appropriate projector RPA and the LSB100.

 

http://www.chiefmfg.com/productdetail.aspx?MountID=123

 

LSB100™ Lateral Shift for LCD/DLP Projector Mounts

http://www.chiefmfg.com/accessories_results.aspx?AccessoryID=314

 

If using the Chief stacker, then the Nav1 and Nav2 mounts are worth looking at as a method of mounting 105mm polarising filters... you may need to modify by extending the arms to move the filters further away from lens, depending on lumens/heat from your projectors.

 

http://downloads.chiefmfg.com/TECH-Drawings-T/NAV1-T.PDF

http://downloads.chiefmfg.com/TECH-Drawings-T/NAV2-T.PDF

 

The ASU Slide Stacker is great for smaller projectors and portable systems.... we have used the single shelf version. placing one projector on bottom and one on the adjustable shelf. You will need to adapt to suit your projectors and to fit the filters. However these have now  been discontinued, but still may be available by some web searching.

 

 

Da-Lite

 

With the demise of the Chief ASU, this might be an alternative. Two sizes available. 

http://www.dalite.com/products/product.php?cID=10&pID=470

 

PDF

http://www.dalite.com/products/spec_pdfs/470.pdf 

 

 

Awater 3D

 

http://www.awater3d.com/en/virtual_reality_systems/

 

Contact : info [at] awater3d [dot] com   for more information. 

 

Premier Mounts - Dual Mount for Ceiling Installation

 

http://www.premiermounts.com/product.asp?PartID=413

 

This is now being discontinued in the UK... may be available from USA or perhaps by special order?

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Projectors

 

With all projectors remember, if they are going to be stacked, you need to check venting arrangements and that close stacking won't void your warranty!

 

BenQ :

We have tested a a number of Benq projectors and have helped build some stereo rigs based on the now discontinued MP77, 3000lms, short throw projector and these seem to have been successful, though the lack of a zoom did mean there was no choice with projector placement. From the current offereing from Benq there are a number of projectors you could consider.... we haven't tested any yet... 

 

Short Throw :

 

 

Install :

 

 

 

 

Two MP771 on the now discontinued Chief ASU stacker. You do need

to remove the support bar under the first shelf to enable the bottom

projector to fit.

 

Casio

Casio : XJ140 and above

 

 

Christie

Christie have been doing stereo for ever :-) and always have a good offering, so worth checking out. But can be pricey...

 

Mitsubishi

Needs to be updated for new projector range;

 

http://vis.mitsubishielectric.co.uk/products/projectors

 

XD3200u & WD3300u - A competitively priced DLP with lens shift and a short throw lens adapter is available. .... Heavy at 10.3kg but still this looks like it could be worth considering for installs. Not been tested.

 

 

NEC :

Needs to be updated for new projector range;

 

>Above : The sadly discontinued LT265 with 3D reform... probably the simplest passive stereo system to set up quickly, and is what we still use for our 3D school shows.

 

http://www.nec-display-solutions.com/c/g/uk/en/Products/Beamer/index.html

3D reform is a great feature, but NEC have dropped it from all but the largest of their DLP's which is a real shame... Our favourite projectors are still our LT 245's and LT260's. You can use NEC's LCD's which still have 3D Reform, but will need to use filters from someone like Awater3D that can be used with LCD's which already have polarised the light pathhttp://www.awater3d.com/en/3d-stereo-polarizers/

 

DLP's to consider NP50 or NP60 or if money and size no problem then NP4000/4001

 

If you want 3D reform then the LT380 LCD is your only option and if lens shift will do then the NP1150 LCD's might do the job... but remember those special filters for LCD from Awater3D

 

Optoma

Optoma offer a wide range of basic DLP's and I know there are many users... but watch out for venting arrangements and check that it is ok to stack them.

 

 

Optoma EX765 :

 

This has Prime shift, which is a limited lens shift feature that will really help with alignment, but will not allow you to go off axis ( as we do with the NEC LT265).

 

One possible downside for a mobile system is that it is really bright for a small screen (2.4m x 1.8) at 4000 lumens if you are in a fully blacked out room, though it does have a standard mode which I assume will be around 3,200 - 3,500 lumens and those extra lumens might help where full black out isn't possible. It is also hefty for a mobile projector at 4.6Kg, so two stacked with filters etc will end up being 10-12kg

 

Throw ratio isn't bad at 1.6 -2.6. This means that at it's closest it will fill our 2.4 x1.8m screen from around 3.9m. This does put it into the second or even third row of our normal seating arrangement.

 

Cost : a search on the web suggests around £1050 + VAT

 

 

Panasonic

Panasonic DLP's can be a very good choice for fixed installs, they seem to be reliable and robustly made. New projectors to be added:

 

 

Projection Design :

 

EVO2sx+

Projection designs entry level projector, does have vertical lens shift, but position of the manual lens shift adjustment is not great when stacking (it is on the top). It is 2,500lms and a 1400 x 1050 resolution which is it's big plus. For entry level installs this is the projector to aim for unless you can stretch to the F20sx+ below :-)

 

http://www.projectiondesign.com/Default.asp?CatID=1389

 

F20 sx+

Another great projector from Projection Design, there are a number of options on lenses and colour wheels, 10 bit and 24/7 operation make this really hard to beat unless you need more power and then the F3 is probably what you are looking for .

 

http://www.projectiondesign.com/Default.asp?CatID=1522

 

F30

The ultimate option....

http://www.projectiondesign.com/Default.asp?CatID=1533

 

Sharp

http://avpartsmaster.netfirms.com/avpmdb/nfoscomm/catalog/index.php?cPath=459_539

 

Sharp XG-PH70X - 5200 ANSI - XGA DLP projector

 

Sharp XG-PH50X - 4000 ANSI - XGA DLP projector

 

These have lens shift and Digital Keystone which seems to be similar to NEC's 3D reform but never been tested.

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Screen Surfaces

Having used a number of surfaces I would suggest Silverfabric from Awater3D :

 

http://www.awater3d.com/en/3d-projection-screens/

 

It is robust, high gain and has great exclusion ... it can appear a little grainy if sitting too close with white images.... but a great screen... and allows use of low lumens projectors. We currently use our LT 260's in eco mode (so around 1900lms) to fill a 240cm x 180cm screen ... on full they are too bright.

 

Other Surfaces

 

Harkness hall

Harkness Hall Spectral 240 3D

This is a soft surface and easily damaged, but does give good results. It is a neutral screen so will require brighter projectors than the SilverFabric. The Harkness Hall fast fold system can be used with this screen.

http://www.harknesshall.com/ss_3d_spectral240.htm

 

Harkness Hall RP 3D

This is a rear projection surface. The Harkness Hall fast fold system can be used with this screen.

http://www.harknesshall.com/ss_3d_rp3d.htm

 

Da-Lite

Da-Lite Silver Matte

Can be purchased in a range of screen formats and types... usually cheap, but we have found that exclusion/ghosting can be a problem with some filters.

 

Da-Lite 3D Virtual Grey

A newer fabric than the Silver matte, the Virtual grey claims to have solved the ghosting problems but at the expense of the viewing angle which is reduced to a half angle of 10 degrees, this and a gain of only 1.85 still seems to suggest that Silver Fabric from Awater 3D (above) is still the best compromise.

 

Da Lite 3D Virtual Black Rear projection :

If you need to maintain high ambient lighting, then if you have the space, rear projection is the answer... though watch out for the limited viewing angle of only 20 deg (half angle = 10 deg)... our own silver fabric screens have a viewing angle of 34 deg and that can be a major limiting factor when setting up in a room with a seating area wider than the screen... so 20 deg could be a problem for large audiences, but perfect for a small dedicated viz suite.

 

Link

 

 

Stewart

Really good screens, but pricey.

 

 

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Technical and other Links

 

Polarisation Help

http://www.advisol.co.il/Technical%20memos.html

 

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The above information is a statement of personal preference by the writer and the DLF takes no responsibility for the accuracy of the information or the views expressed.

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