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As cool as this is, it's not really a hologram. This is an example of Pepper's Ghost, which is also what's used to project images into your field of vision usin

As cool as this is, it's not really a hologram. This is an example of Pepper's Ghost, which is also what's used to project images into your field of vision using Google Glass.

sp332 14y ago
I was confused for a second because Pepper Potts is the love interest in Iron Man. But you meant https://en.wikipedia.org/wiki/Pepper%27s_ghost https://en.wikipedia.org/wiki/Pepper%27s_ghost (which was also the technique used for Tupac's re-animation at Coachella last year).
- solistice 14y ago
  I loved how the public went crazy over a technology "invented" in 1873 and how people where like "finally holograms".
brador 14y ago
What are the requirements to define something as a hologram?
- sp332 14y ago
  Today's average 3D displays are "stereoscopic": they have 2 views, for the left and right eye. A real hologram shows the whole object, so multiple people can walk around it and see it from every angle at once. But this isn't even stereoscopic. This is just a 2D image reflected on a piece of glass.
- malandrew 14y ago
  I think you need elements of light interference and diffraction for something to be a hologram. It's essentially a way to "record" light the same way you can record sound in grooves or magnetic tape.
- fresnel100 14y ago
  Holography entails the diffractive reconstruction of the wavefront corresponding to a 3-D scene, and optical holograms are generated using the coherent interference of light scattered from a 3-D scene with that from a second reference beam. Holography, by definition, necessitates scene reconstruction via diffraction. In the case of an electro-holographic display, diffraction patterns corresponding to 3-D scenes are computed and displayed on suitable light modulators to achieve wavefront reconstruction. This technology is still in its infancy, so you probably won't see anything truly holographic in the marketplace for some number of years. As cool as this demonstration is, it's using a 19th-century technique -- "Pepper's Ghost" -- and cannot correctly be called holographic. Here's work out of MIT depicting the true state-of-the-art in real-time electroholography: http://web.mit.edu/newsoffice/2011/video-holography-0124.html http://web.mit.edu/newsoffice/2011/video-holography-0124.htm....
ajacksified 14y ago
Classic HN, pedantic comments about this not being a hologram. You know what it is? It's a really cool demo of controlling a perceptually 3D image using a motion controller. Let's have, say, a discussion about the LeapMotion[1] (which is awesome, I have one) or the fact that it's using Javascript (this looks like it is using the packaged WebGL demo[2]). The LeapMotion is quite nice to use with WebGL / three.js. [1] https://github.com/leapmotion/leapjs https://github.com/leapmotion/leapjs [2] https://www.leapmotion.com/ https://www.leapmotion.com/
- brador 14y ago
  How did you get a leap motion? What do you think of it?
  - ajacksified 14y ago
    I was lucky enough to give a presentation at an Intel "Perceptual Computing" meetup (their version of the LeapMotion), and I met a dev advocate from LeapMotion. I think it's very interesting; the API is solid, and it's really easy to use with Javascript because you can interface with it directly through a Websocket server. That, plus three.js, means you can do some interesting things with examining 3D models. It isn't a far stretch to see medical and industrial applications, as well as interesting games (Infinity Blade, laptop edition?) There are a few companies working on this at once[1]; I think it's definitely something to keep an eye on. It seems like a natural evolution of webcams. [1]http://news.ycombinator.com/item?id=5339266 http://news.ycombinator.com/item?id=5339266
  - jamesbritt 14y ago
    I'm not ajacksified, but I have a Leap, which I got by joining the developer program. I love it. I've been writing about it at http://leaphacking.com http://leaphacking.com Leap has announced that the devices will be available to the public on May 13. I've been hacking around using JRuby and JavaScript. It's quite nice to work with, and so far my biggest issues are thinking through just how to handle user movement (i.e. what hand/finger combinations and movement should equate to what action). It's a nice compliment to the XBox Kinect, too. Gesture recognition has been added so I need to spend a bit of time with that today.
jonmrodriguez 14y ago
Someone could make a better version where the Pepper's Ghost display is an autostereoscopic stereo 3D display that uses a either a parallax barrier or lenticular lenses. http://en.wikipedia.org/wiki/Parallax_barrier http://en.wikipedia.org/wiki/Parallax_barrier As long as the user lines up with the center line properly, the image would be both "ghostly" as here and also stereo 3D.

As cool as this is, it's not really a hologram. This is an example of Pepper's Ghost, which is also what's used to project images into your field of vision using Google Glass.

sp332 14y ago

I was confused for a second because Pepper Potts is the love interest in Iron Man. But you meant https://en.wikipedia.org/wiki/Pepper%27s_ghost https://en.wikipedia.org/wiki/Pepper%27s_ghost (which was also the technique used for Tupac's re-animation at Coachella last year).

solistice 14y ago
I loved how the public went crazy over a technology "invented" in 1873 and how people where like "finally holograms".

brador 14y ago

What are the requirements to define something as a hologram?

sp332 14y ago
Today's average 3D displays are "stereoscopic": they have 2 views, for the left and right eye. A real hologram shows the whole object, so multiple people can walk around it and see it from every angle at once. But this isn't even stereoscopic. This is just a 2D image reflected on a piece of glass.
malandrew 14y ago
I think you need elements of light interference and diffraction for something to be a hologram. It's essentially a way to "record" light the same way you can record sound in grooves or magnetic tape.
fresnel100 14y ago
Holography entails the diffractive reconstruction of the wavefront corresponding to a 3-D scene, and optical holograms are generated using the coherent interference of light scattered from a 3-D scene with that from a second reference beam. Holography, by definition, necessitates scene reconstruction via diffraction. In the case of an electro-holographic display, diffraction patterns corresponding to 3-D scenes are computed and displayed on suitable light modulators to achieve wavefront reconstruction. This technology is still in its infancy, so you probably won't see anything truly holographic in the marketplace for some number of years. As cool as this demonstration is, it's using a 19th-century technique -- "Pepper's Ghost" -- and cannot correctly be called holographic. Here's work out of MIT depicting the true state-of-the-art in real-time electroholography: http://web.mit.edu/newsoffice/2011/video-holography-0124.html http://web.mit.edu/newsoffice/2011/video-holography-0124.htm....

ajacksified 14y ago

Classic HN, pedantic comments about this not being a hologram. You know what it is? It's a really cool demo of controlling a perceptually 3D image using a motion controller. Let's have, say, a discussion about the LeapMotion[1] (which is awesome, I have one) or the fact that it's using Javascript (this looks like it is using the packaged WebGL demo[2]). The LeapMotion is quite nice to use with WebGL / three.js. [1] https://github.com/leapmotion/leapjs https://github.com/leapmotion/leapjs [2] https://www.leapmotion.com/ https://www.leapmotion.com/

brador 14y ago
How did you get a leap motion? What do you think of it?
- ajacksified 14y ago
  I was lucky enough to give a presentation at an Intel "Perceptual Computing" meetup (their version of the LeapMotion), and I met a dev advocate from LeapMotion. I think it's very interesting; the API is solid, and it's really easy to use with Javascript because you can interface with it directly through a Websocket server. That, plus three.js, means you can do some interesting things with examining 3D models. It isn't a far stretch to see medical and industrial applications, as well as interesting games (Infinity Blade, laptop edition?) There are a few companies working on this at once[1]; I think it's definitely something to keep an eye on. It seems like a natural evolution of webcams. [1]http://news.ycombinator.com/item?id=5339266 http://news.ycombinator.com/item?id=5339266
- jamesbritt 14y ago
  I'm not ajacksified, but I have a Leap, which I got by joining the developer program. I love it. I've been writing about it at http://leaphacking.com http://leaphacking.com Leap has announced that the devices will be available to the public on May 13. I've been hacking around using JRuby and JavaScript. It's quite nice to work with, and so far my biggest issues are thinking through just how to handle user movement (i.e. what hand/finger combinations and movement should equate to what action). It's a nice compliment to the XBox Kinect, too. Gesture recognition has been added so I need to spend a bit of time with that today.

jonmrodriguez 14y ago

Someone could make a better version where the Pepper's Ghost display is an autostereoscopic stereo 3D display that uses a either a parallax barrier or lenticular lenses. http://en.wikipedia.org/wiki/Parallax_barrier http://en.wikipedia.org/wiki/Parallax_barrier As long as the user lines up with the center line properly, the image would be both "ghostly" as here and also stereo 3D.