USC Team Creates 360° Holographic Display with Mirrors, Perhaps Smoke
Using a mirror spinning at a ridiculous 20Hz—20 revolutions a second—researchers at the USC Institute for Creative Technologies have created a fully-functioning monochrome "holographic" display. While holographic displays are pretty common, most implementations don't allow true 360-degree walkarounds. This puppy does.
I was going to pooh-pooh the practicality of home implementations, but surrounding the spinning mirror with a protective bubble wouldn't be that impractical. Getting the overhead projector with beams in the image on the mirror into something more compact would likely be a bigger challenge.
However you slice it: very, very cool.
ICT Researchers Win "Best Emerging Technology" Award at SIGGRAPH 2007 [CGSociety.org via Geekologie via Technabob via Archipass via Swiss Miss via Core77 via Engadget]
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I wonder how well it would scale up? I mean, it's really cool at that size, but not all that useful for displaying information to more than a handful of people at a time.
Basically, when will will I get a full-size version to put in the middle of my living room?
I don't know if I want to sit near ANYTHING spinning at 72,000 RPM.
Ehh, many of us put something spinning at 5,400 - 10,000 rpms on our laps. (hard drive) If it's encased safely, it's not a huge deal.
72,000 RPM? Where did that come from? 20 RPS x 60 = 1200 RPM, neh?
does anyone here actually have a vague idea how this thing works? How do you get 3d depth from a 45 degree mirror?
Also interesting that the mirror appears to be made of mylar or similar...
Olly.
Not holographic, it's a time multiplex volumetric or angular display.
The concept is as old as the hills.
You spin a tilted disc with a really fast DLP projector. At a series of discrete positions you project the cross section of the scene that the disc describes at that position. Or in this case you project the view that you would have at the angle a mirror disk is at at that moment. The "holographic" diffuser simply allows for a controlled scatter of the light.
See what Actuality has done with this:
http://www.actuality-systems.com/site/content/perspecta_display1-9.html
Two big problems with the tech. First it requires a really fast spinning disk, with the associated wear problems. Second, due to the need to spin structures at a high rate of speed it is really hard to scale. Finally, it depends on the frame rate of the projector.
At full blast, a DLP (DMD) projector bangs out 16,300 binary (white or black) images "slots" a second. To get greyscales you have to alternate black and white pixels in adjacent frames so that they average to gray. To get n-bit gray you need (2^n)-1 slots per image. To get color you have to do this three times while illuminating the DLP chip with red green and blue light (or use 3 DLP chips at massive cost). So if you want 8 bit gray you only get 60 frames per second which won't work here. At 8-bit color (3-bits red 3-bits green 2-bits blue) you can generate 531 images per second, but since you have to update at greater than ~50 frames per second to get flicker fusion you are limited to 8-15 views per rotation. This is enough to get look around, but only provides stereo fusion at ~15 selected points in the scene. Also the bandwidth of the raw output is 12 Gbit/sec, and DVI tops out at 7.4Gbits/sec. Actually, without serious mojo you are limited to a 240 image per second update rate which matches the described 15 fps update pretty closely.
So, neat implementation but scaling up the physical components is going to be a b***ch on wheels (with wheels spinning at 7,200 rpm).
How do you get 3d depth from a 45 degree mirror?
I'm a fair dunce, but I could guess that the angle is just to do with the positioning of the projectors. If they were at horizontal people'd keep getting in the way of the image, like when some giantoid person stands up in the back row of a cinema.
Many Bothans died to bring us this information...
this is perfect example of Spatial Visualization Environment and Core Rendering Software ....its actually a drivers based API which Provides interactive compatibility with many supported 3D applications ...nice collection....i have also seen a great visualization of low animation example of harry porter article in....
http://4engr.com/press/catalog/2038/index.html