[Visualpython-users] Fwd: Vpython active stereo 3D -- Will it work with the new Acer Aspire 5738DG that has 3D LCD display screen?

[Stanley S. <ove...@ea...>]

Bruce,

Maybe you're right about the passive nature, rather than frame-switching.
I was just guessing.  They could be just merging the left and right images
into the alternate lines, rather than doing frame-sequential switching.
There isn't any technical data that I've found yet.  However, a few reviews
I've read have mentioned seeing faint horizontal lines when viewing without
the polarizing glasses.

I agree that it's odd that the vertical resolution has to be cut in half
rather than the horizontal.   I guess it doesn't really matter in terms of
the local resolution, since either way the number of pixels per inch would
be cut in half in 3D mode.  I suppose those fast-moving shooter games still
look ok anyway, since they are animations and fairly low resolution would
still look ok.

Asus recently released a 3D laptop, but it uses Nvidia graphics with
frame-sequential method that requires the active eyeglasses (LCD shutters).
That method would not cut the resolution in half.  But it's much more
expensive than the Acer.

After posting my message here, I looked around for 3D monitors and found
that there are many.   They used to cost thousands of dollars, but now you
can get them for a few hundred.   Nvidia's kit with eyeglasses and switching
signal device costs about $200.  A GeForce 8 series or better graphics card
is necessary, for about $250 (GeForce 8800). So to get 3D into a desktop,
you'd need to spend about as much as the cost of the entire Acer laptop.
But, you'd have lower resolution with the Acer.  It might be good enough for
Vpython models, though, if Acer provides an OpenGL driver for it.

Stan


On Sat, Dec 12, 2009 at 8:26 PM, Bruce Sherwood <Bru...@nc...>wrote:

> As far as I know no one has had access to one of these stereo devices to
> try VPython stereo modes. There even exist screens that require no
> glasses at all, but you have to hold your head just right: baffles allow
> your right eye to see only the odd-numbered vertical display lines, and
> your left eye to see only the even-numbered vertical display lines.
>
> For the Acer that you describe, it's possible that scene.stereo =
> 'passive' (not active) would work, depending on how they've set up the
> interface to OpenGL (or if they even have an interface to OpenGL; what
> little I could find on the web about this product talks only about games
> using DirectX 9). The passive mode is intended for use with graphics
> cards that can drive two projectors, each with polarizers, whose images
> are superimposed on a metallic screen, which does not destroy
> polarization (ordinary projector screens return polarized light as
> unpolarized). Viewers wear polarized glasses.
>
> Even without such a graphics card you can observe the scheme. With
> scene.stereo = 'passive' you get two images on the screen, one for each
> eye. If you use small enough images and are able to look "walleyed" you
> can see true stereo without glasses. Or set screen.stereo = 'crosseyed'
> and view the two images cross-eyed.
>
> I don't see why the Acer would show alternate frames. Since there is
> polarization separation there's no reason not to display the left and
> right images at the same time. It's only active stereo with shutter
> glasses (and no separation by polarization) that involves whole left
> images in one frame and whole right images in the next frame, with
> shutters letting only one eye at a time to see the screen. Active stereo
> does require high frame rate, but passive stereo does not.
>
> You say that they've chosen to have horizontal lines polarized, yielding
> 1366 x 384. This seems odd; if they polarized vertical lines the
> resolution would be 683 x 768, which would seem to me to be a more
> reasonable choice.
>
> Bruce Sherwood
>
> Stanley Sokolow wrote:
> > Acer has started selling a rather affordable laptop with a special 3D
> > LCD screen.   I remember reading a whitepaper a couple of years ago by
> > the guys who inventing this type of display, if it's the same
> > technology.   The LCD screen has an additional layer in front which
> > has alternating horizontal lines of polarizing filters so that even
> > numbered display lines are polarized one way and odd numbered lines
> > are polarized opposite.   With appropriate drivers, the graphics chip
> > shows left eye images polarized one way, then in the next frame the
> > corresponding right eye image polarized opposite.   By wearing simple
> > polarized glasses that have left and right polarizing filters oriented
> > at 90 degrees to each other, the observer sees stereoscopic 3D.  The
> > glasses are passive, not the active shutter type.  The Acer has a 120
> > Hz display, so each eye is updated at 60 Hz, which is fast enough that
> > no flicker would be seen.  One drawback is that the vertical
> > resolution is effectively cut in half in stereo mode since every other
> > line is used.  That is, the stereo mode would in effect be 1366 x 384,
> > since the Acer specs say the "maximum resolution is 1336 x 768".
> >
> > Here's a link to one place that sells this new Acer:
> >
> http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=5285802&CatId=4938
> > <
> http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=5285802&CatId=4938
> >
> > .   Try www.nextag.com <http://www.nextag.com/> to find competitive
> > prices.
> >
> > By the way, if you are thinking of getting one of these and using it
> > with other 3D glasses besides the ones that come with the laptop, be
> > sure to get the correct type of polarizing 3D glasses -- some have the
> > eyes oriented with the filters passing vertical and horizontal
> > polarized light, but others have the filters oriented diagonally at 90
> > degrees to each other's polarization.  I don't have the laptop myself,
> > so I don't know which kind it needs.
> >
> > Does anyone know if this laptop would display Vpython's active-mode
> > stereo correctly?   I've only read about Vpython doing active stereo
> > with the LCD shutter type of stereo, but it seems that this might be
> > just the same from the API, with the driver and graphics chip just
> > doing the alternating screens a different way at the display side.
> >
> > Stan Sokolow
> > ------------------------------------------------------------------------
> >
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