Setting up the projectors so they all match is difficult. The brightness and color of each projector will change as the lamps and LCD chips age. If you are using (as we did) projectors with different amounts of lamp time the color will not match. If they are all new projectors they should be close, or you should be able to adjust color temperature, brightness and contrast to match.
The accurate alignment is affected by zoom setting, keystoning and even focus - a few tiny errors add up quickly - we set up the center projector first, adjusting size and position, then we measured the width of the image on the screen. This measurement then became the measurement from lens center to lens center from the center projector to each side projector. This seemed to lessen the side to side keystoning - if you have to twist the projector on the mount to get the image edges to align, the keystoning will make it really hard to get a seamless image. I used a background image to align the projectors, then changed it to black once I had them aligned. The alignment is pretty good, but the color difference is distracting. We will swap out the offending projector to hopefully correct this.. FWIW Jim Jim Wellings Video Network Engineer/Operations Supervisor TSS Utah State University Logan UT 84322-8500 435-797-0674 435-770-2846 jim.welli...@usu.edu<mailto:jim.welli...@usu.edu> >>> "Osland, CD (Chris) " <c.d.osl...@rl.ac.uk> 9/27/2004 3:34:27 AM >>> The main 'trick' is to set the background to black. Then, when two images don't quite abut, or overlap, there is no double intensity or gap in the background. Then it's just a matter of normally arranging the windows so they don't span projectors. Once you get into edge-blending (the term that describes the handling of overlapping areas) you are into SERIOUS amounts of money for hardware: I haven't seen a software solution. You can do a bit with the intensity control on each projector, but there will usually be a bit of a mismatch with commodity level projectors. Another thing I do is run our 1024x768 (native) projectors with 1280x960 signals. This gives a dramatic increase in the number of pixels (2 such projectors have more pixels than 3 1024x768 projectors) and makes it much easier to fit 3x3 medium size windows on each projector, without using the shift-m trick which crops edge! s off the windows (maybe losing vital bits of some carefully judged framing). For AG images the results are fine; for PowerPoint etc. they are acceptable. HTH Chris ____________________________________________________________________ Chris Osland Office tel: +44 (0) 1235 446565 Digital Media and Access Grid Medialab tel: +44 (0) 1235 446459 BIT Department Access Grid room tel: +44 (0) 1235 445666 e-mail: c.d.osl...@rl.ac.uk Fax: +44 (0) 1235 445597 CCLRC Rutherford Appleton Laboratory (Bldg. R18) Chilton, DIDCOT, Oxon OX11 0QX, UK [The contents of this email are confidential ! and are for the use of the intended recipient only. If you are not the intended recipient do not take any action on it or show it to anyone else, but return this email to the sender and delete your copy of it.] > -----Original Message----- > From: owner-ag-t...@mcs.anl.gov [mailto:owner-ag-t...@mcs.anl.gov]On > Behalf Of Natalia Costas Lago > Sent: 25 September 2004 17:18 > To: ag-t...@mcs.anl.gov > Subject: [AG-TECH] screens/projectors set up > > > > Hi everybody, > > > We are in the latest stage in building our node. The problem > we have right > now is how the projectors can't be tunned so the transition from one > screen to the next is smooth (it seems to be very difficult from the > technicians to tune the position and the color). I wonder is > there is some > trick! AG users have to fix this. > > Maybe the screens overlap and there is some software that handles the > overlapping area? > > We have another problem as the central projector seems to > have a slightly > different brightness (even though the settings are the same for the 3 > projectors). But we havent tried to fix this so far. > > Any help about this issue is greatly appreciated. > > Kind regards, > Natalia. > > > ----------------------------------- > Natalia Costas Lago > mailto: nata...@cesga.es > > Centro de Supercomputacion de Galicia (CESGA) > Center for High Performance Computing > > Avenida de Vigo, s/n Campus Sur > 15705 Santiago de Compostela - SPAIN > Tel: +34 981 56 98 10 > Fax: +34 981 59 46 16 > http://www.cesga.es/ > > >
