[AG-TECH] AG Projector options?

[Markus Buchhorn]

Hi Eric

At 04:34 PM 9/09/2002 -0400, you wrote:
>I was wondering if you have received any more information on projectors that you wish to share, We seem to be in the same position as you are/were. We're considering PLD projectors instead of LCD projectors but still doing research for our AG Node.

We haven't committed yet either, but we're about to put out an RFT. The main additional suggestions I got was in the responses to the list - basically adding:

 - heat output
 - noise level

to the list below. Conversely, people indicated going to 1280 (SXGA) and/or 120Hz seems to put a major hurdle under the price (factor of 2-3).

Other comments I heard round the traps:

On the DLP vs LCD front: In general, DLP's seem to be more popular. They are generally better contrast (blacker blacks), more lumens for your Watts, and run to higher frequencies (so you don't smear the mouse cursor as it moves on the screen). DLP's output is also unpolarised, or circularly polarised. LCDs are linearly polarised. If you're looking to do stereo projection with polarisation on two projectors, you can either drop a simple polarising filter in front of a DLP's lens, or get an LCD projector that already has it appropriately turned. Putting a polarising filter in front of an LCD's lens is likely to block most of your light on one projector :-)

These are *generally* seen as true. However, there do seem to be some models/vendors exceptions, where LCDs have caught up or moved ahead. <sigh>.

There are also some CRT-based projectors (e.g. some 3-Guns), which can perform extremely well - but cost waayyy more.

One room-design issue - having more than one input port for VGA could be useful for cabling design. If your room is used for something other than AG at times, say a visitor with a laptop, it may avoid fiddling with VGA patch cables in your AG rack. I suspect we'll just go with a VGA switch somewhere.

One cabling question - support for DVI rather than VGA cabling. It seems like most high-end graphics cards support DVI outputs, some projectors support DVI inputs. I haven't seen it definitively stated anywhere, but the suggestion is that DVI can run over much longer cables than VGA. That could be quite useful. Whether that's better/cheaper than a VGA signal amp? <shrug>.

Finally, an optics feature - horizontal keystoning. All projectors do vertical keystone (optically, to first order), so that you can roof mount or table mount, and the lens is level with the top or bottom of the projected image and the image looks square. If you want to use two projectors for polarisation stereo, they may need to be stacked. If you have a room layout issue, you may want to cluster your projectors. If you wanted to get a better aspect ratio on the display, you may want to use your projectors sideways (!). In all of these, you may need horizontal keystoning as well as vertical. It sounds like some projectors can do it digitally today, some will hopefully be able to do it optically in the future.

How important you rate each of the above and below depends on each site/room. I hope at least it gives you some more questions to ask that lets you rank replies...

I'd appreciate any additional comments/suggestions.

One additional question, which is not so much projector-related, but influences it: Which, if any, multi-head graphics cards, and which, if any, operating systems, support a multi-head display with different display resolutions? Can I use 3 of XGA and 1 of SXGA? Or 2 XGA and 2 SXGA (say with 2 dual-output cards)? 

Cheers,
        Markus

>> - resolution: 1024x768 minimum, 1280x1024 better (real, not interpolated)
>> - brightness: the more lumens the better 
>> - inputs: (besides VGA cable) composite? component? (analogue, digital?)
>> - keystone correction: optical not electronic? (quality)
>> - zoom, focus: manual not electronic? (cost)
>> - remote control: are there any with serial ports instead of an IR remote?
>> - lens options: ability to do ~1:1 (short throw -> large display area) or better?
>> - frame rate: 60-70Hz is common. 100-120Hz for active stereo projection
>> - filter options: various polarisation filters for passive stereo projection
>> - colour correction options: Handling different light-bulbs' effective temperatures, to give a natural reproduction (of whatever has been captured - a separate issue).
>> - image flip: floor vs roof mounting, front vs back projection
>> - oh yeah: COST :-) (start up capital, consumable bulbs)


Markus Buchhorn, ANU Internet Futures Project,        | Ph: +61 2 61258810
Markus.Buchhorn at anu.edu.au, mail: Bldg #108 - CS&IT   |Fax: +61 2 61259805
Australian National University, Canberra 0200, Aust.  |Mobile: 0417 281429