goss@SNOW-WHITE.MERIT-TECH.COM (Mike Goss) (09/07/89)
Regarding the continuing discussion of active vs. passive stereo viewing techniques, there is another point which is relevant to the choice of system. It is sometimes necessary for the user of a stereo system to view other, non-stereo video monitors in addition to a stereo display. With active glasses, it is necessary to remove the glasses to view other video sources; the glasses cause severe flicker otherwise. With passive glasses, it is still possible to view other video sources without flicker. Also, if multiple stereo monitors are in use, active glasses require that all video monitors have synchronized refresh cycles in order to be viewed simultaneously; passive glasses do not have this requirement. ------------------------------ Mike Goss Merit Technology Inc. (214)733-7018 goss@snow-white.merit-tech.com
thant@horus.sgi.com (Thant Tessman) (09/08/89)
In article <8909071236.AA15114@snow-white.merit-tech.com>, goss@SNOW-WHITE.MERIT-TECH.COM (Mike Goss) writes: > Regarding the continuing discussion of active vs. passive stereo viewing > techniques, there is another point which is relevant to the choice of > system. It is sometimes necessary for the user of a stereo system to > view other, non-stereo video monitors in addition to a stereo display. > With active glasses, it is necessary to remove the glasses to view other > video sources; the glasses cause severe flicker otherwise. StereoView (CrystalEyes) have a button on the side that turns them clear, so not only is there no flicker, but there is very little light being cut out, just like wearing clear glasses. This is even better than passive glasses which always cut out at least half the light. > Also, if multiple stereo monitors are in use, active glasses require that > all video monitors have synchronized refresh cycles in order to be viewed > simultaneously; passive glasses do not have this requirement. You are right about viewing them simultaneously, but the StereoView glasses sync to the monitor you are facing, so it is possible to look back and forth between more than one monitor and always be synced to the one you are looking at. thant -- ----------------------------------------------------------------------------- There's a pattern there to see, and the point will soon be clear to me. -Stewart Copeland -----------------------------------------------------------------------------
naegle@oberon.sgi.com (David Naegle) (09/09/89)
In article <8909071236.AA15114@snow-white.merit-tech.com>, goss@SNOW-WHITE.MERIT-TECH.COM (Mike Goss) writes: > [] It is sometimes necessary for the user of a stereo system to > view other, non-stereo video monitors in addition to a stereo display. > With active glasses, it is necessary to remove the glasses to view other > video sources; the glasses cause severe flicker otherwise. With passive > glasses, it is still possible to view other video sources without flicker. > Also, if multiple stereo monitors are in use, active glasses require that > all video monitors have synchronized refresh cycles in order to be viewed > simultaneously; passive glasses do not have this requirement. It is true that active eyewear will cause you to see slow-moving dark bands on a non-stereo video monitor. That's why one of the four buttons on the StereoView eyewear is a 'clear' mode button. When you press this button, you can look at non-stereo video screens with no problems. Press it again, and you're back in stereo mode. This is somewhat less inconvenient than actually removing the glasses, in most applications. To deal with the situation where multiple stereo monitors are in use, the infrared transmitter is designed to broadcast a wide-angle pattern of stereo field (right/left) signal, and the glasses are designed to 'see' a narrow pattern. That way, the eyewear will lock onto the stereo signal of whichever video display you're viewing at the moment. There *are* arrangements of monitors which can cause trouble, like trying to view stereo on two unsynchronized monitors placed side-by-side, especially from the maximum range. This arrangement puts the stereo transmitters too close together for the eyewear to lock onto one or the other reliably, since the angle of incidence is nearly identical for both I.R. beams. Usually, though, if you have to view multiple stereo screens at the same time, they can be arranged so that the I.R. beams don't come from nearly the same place. Considering that it would cost $16K-$25K for two passive-eyewear stereo systems to handle the rare instances which cannot be handled as described above, most users would just do without stereo in those cases. If you want theatre viewing, use a z-screen, or better yet, a polarizing stereo video projector. StereoView glasses are meant for low-cost, one-on-one applications. > > ------------------------------ > Mike Goss > Merit Technology Inc. > (214)733-7018 > goss@snow-white.merit-tech.com David Naegle Graphics Hardware Manager naegle@sgi.com
lmeyer@well.UUCP (lhary meyer) (09/09/89)
In response to Mike Goss at Merit: The CrystalEyes/StereoView glasses have a BRIGHT mode ( rear switch, right side) that opens both eyes & stops shuttering. Thus you can look at another monitor without "beat bars". The IR transmitter has a very wide dispaersion beam, nearly 180 degs. but the glasses have a narrow acceptance angle, only 20-30 degrees, so they only "see" the monitor that you're looking at. The IR emitters have a HI/LOW switch to provide a range of about 4'/10' to allow fairly close monitors without syncronizing them. Still, if you prefer the ZScreen approach, we intend to continue them until nobody wants them anymore. Take your pick!! Lhary Meyer // Stereographics