

Prototyping a 3D light field display video projector array - zackmorris
http://gl.ict.usc.edu/Research/lfd/

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pierrec
This is a surprisingly simple technique for multiscopic display, a back-to-
basics approach that relies of the existence of extremely small or
concentrated projectors. This research is from 2011, but like most multiscopy
research, it's actually pretty far out into the future.

It's interesting to consider how such displays would require a different
approach to video creation and viewing. Notably, how many viewers can share
one display? A single viewer with a television-sized display will experience
immersive stereoscopy. The video can be prepared as a window, and incite the
viewer to lean left and right to get different perspectives. As you add more
viewers, the display's multiscopy becomes less and less interesting, though I
imagine it can remain so, in the same way that theater has more dimensionality
than cinema.

Also a semantic nitpick: in the overview they call it "autostereoscopic" but I
think "automultiscopic" is more explicit, and used in existing literature [1].
The reasoning is that, for example, a creature with more than two eyes would
still get a different perspective for each eye, so there's nothing inherently
"stereo" about the display.

[1]:
[http://web.media.mit.edu/~mhirsch/hr3d/taxonomy.png](http://web.media.mit.edu/~mhirsch/hr3d/taxonomy.png)
(from
[http://web.media.mit.edu/~mhirsch/hr3d/](http://web.media.mit.edu/~mhirsch/hr3d/))

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bane
I'm not really familiar with this field at all, but does this basically give
the effect of an in-air 3d display?

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pierrec
You mean Star Wars style? In which case the answer is no, not really.
Multiscopic displays have never been properly represented in SF movies, as far
as I'm aware. A perfect automultiscopic display would be very much like a
window, with the video being able to show any kind of dynamic perspective on
the other side of the window. Actually it's more than a window, since elements
can give the impression of being in front of the window, but such elements
would clip at the edge of the window if the viewer leaned too far out. So the
3D could only be "in-air" as long as the screen is behind it.

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bane
Yeah basically. It may not actually be hanging in the air, but would it more
or less look like it?

Or would it look more like a 3d TV, a window on the wall that has the
appearance of volume, except with this research you can also move around a bit
and the object changes as expected?

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sp332
The difference with current 3D TVs is that you only get two angles, one for
each eye. Everyone who looks at the TV from any angle gets the same two views.
With this tech, the view each eye gets depends on where it is physically, so
you can move your head around to get a different angle, and multiple people
can get different angles all at once.

Edit2 (ignore previous edit): Another advantage is that you gain the ability
to focus your eyes (each eye) at the correct depth for the object that you're
looking at. With 3D TVs, each eye has to focus at the depth of the display all
the time. The only depth cue is the angle between your eyes.

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ssfrr
If you're interested in that you may also like Matt Hirsch and Gordon
Wetzstein's more recent work from the MIT Media Lab (they cite this paper):

[http://web.media.mit.edu/~gordonw/CompressiveLightFieldProje...](http://web.media.mit.edu/~gordonw/CompressiveLightFieldProjector/)

Similar concept optically (as far as I can tell, it's not really my field) but
solves some of the practical implementation issues (particularly the one-
projector-per-pixel problem).

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Cloudy
Wow this seems expensive and bulky compared to a headset with a hi resolution
screen a few inches away from the eyes.

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ChuckMcM
It does, except that this technique can, in theory create a holodeck like
experience for a group not wearing headsets. That would be better for training
and simulation.

For a while I was looking at building a basement with a "picture window" which
was really just a view from the floor above ground. "Normal" displays don't
simulate a good window experience, a curved display can give a decent
simulation if you don't move (and that is what they do in flight sims as you
are constrained to your seat), but a light field simulation would really give
you the feeling you were looking out of the window directly, even when moving
around your point of view.

