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As a project, I am examining the possibility of physics from a science fiction book: Speaker for the Dead. The best physics-related concept I have found has to do with the 3D projections that the computers generate. I have researched a lot about holograms, and know mostly how a projection could be made differently than OSC explains in Speaker but I don't know: Why are 3D holographic projections into the air impossible?
So I defer to you,Hatrackers (hope there are physicists in the crowd).
Posts: 1 | Registered: Jun 2009
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Do you know they are impossible? Holograms are basically a parlour trick at the present stage of the technology, because the projectors are expensive. For all you know, someone can do this and you just never saw it, because how many holograms do you see anyway?
Posts: 10645 | Registered: Jul 2004
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Might help to quote the relevant text, quizzical.
I don't know of a way to make light head for my retina from an arbitrary place in the air. Some kind of matrix other than air seems like it'd be required. However, you can have various things in the atmosphere and still call it "air", so there are probably some possible mechanisms that would pass the standards of most speculative fiction.
Looks like that heliodisplay is using water droplets. Are you sure it's 'holographic' Herblay? Or is it just using the droplets as a projector screen?
Posts: 4287 | Registered: Mar 2005
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I don't buy it. Light doesn't just stop. Something has to stop it. If nothing stops it, it'll just continue on until it attenuates. That Heliodisplay has to be creating something physical, mist or something of that sort, that the light can reflect off of.
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We see light that either comes from a source--Sun, flame, glowing filament,etc, or that is reflected off of a surface--the moon, the solid surface of a wall or my bald head.
There is no surface in the air to reflect light off of. (Some work has been done with water, other liquids, even smoke.)
However, I have, in my magic shop, a curved mirrored bowl with a small hole at the top. Place an item in the bowl and a holographic image of it seems to be sitting on the top of that hole--in the air.
Posts: 1941 | Registered: Feb 2003
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quote:Originally posted by Lisa: I don't buy it. Light doesn't just stop. Something has to stop it. If nothing stops it, it'll just continue on until it attenuates. That Heliodisplay has to be creating something physical, mist or something of that sort, that the light can reflect off of.
The "charge base unit with 1L of regular tap water" seems to be a clue, here...
quote:Originally posted by Darth_Mauve: However, I have, in my magic shop, a curved mirrored bowl with a small hole at the top. Place an item in the bowl and a holographic image of it seems to be sitting on the top of that hole--in the air.
A similar effect was used in Sega's "Time Traveler" video game cabinet. A modestly nifty-looking gimmick, but not enough to make everyone want to adopt it for their games.
Posts: 3826 | Registered: May 2005
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There are a couple of other holographic projectors in development. Most (if not all) of them use water vapor as a medium. The biggest drawback is that for an image to look good, the air has to be completely still. Otherwise, it looks wobbly, like the ones in Star Wars.
Kind of ironic --- I always figured that if we saw sci-fi technology in the real world, it would be Star Trek . . . not Star Wars.
Posts: 688 | Registered: Nov 2008
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quote:Originally posted by Darth_Mauve: We see light that either comes from a source--Sun, flame, glowing filament,etc, or that is reflected off of a surface--the moon, the solid surface of a wall or my bald head.
There is no surface in the air to reflect light off of. (Some work has been done with water, other liquids, even smoke.)
However, I have, in my magic shop, a curved mirrored bowl with a small hole at the top. Place an item in the bowl and a holographic image of it seems to be sitting on the top of that hole--in the air.
quote:Originally posted by Herblay: There are a couple of other holographic projectors in development. Most (if not all) of them use water vapor as a medium. The biggest drawback is that for an image to look good, the air has to be completely still. Otherwise, it looks wobbly, like the ones in Star Wars.
Kind of ironic --- I always figured that if we saw sci-fi technology in the real world, it would be Star Trek . . . not Star Wars.
Are the other ones 2d like the Heliodisplay? I'm really not sure that "holographic" is the right adjective for that one.
I think we'll get holographic simulations fed to our nervous systems through digital interface sooner than we'll get convincing external holographic display technology.
Posts: 4287 | Registered: Mar 2005
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With camera vision algorithms getting better and cameras getting smaller, my money is on "fake" holograms via Augmented Reality (displays & position tracking cameras embedded in contact lenses, eyeglasses, etc.) long before true "holograms". On the other hand, glasses-less panel-based 3D displays are starting to look mass-producible...
Posts: 353 | Registered: Sep 2003
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I was thinking the same thing. Digital images on glasses, contact lenses to simulate holograms. I have a GURPS rpg book on my shelf called Transhuman space that goes that route.
Posts: 305 | Registered: Jan 2008
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What's your real question? Cuz one of the first holograms I saw was of a microscope with a fly on the slide projected into the air. And if you looked through the (projected) microscope's eyepiece, you'd see a magnified fly.
Posts: 8501 | Registered: Jul 2001
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quote:Originally posted by Darth_Mauve: We see light that either comes from a source--Sun, flame, glowing filament,etc, or that is reflected off of a surface--the moon, the solid surface of a wall or my bald head.
There is no surface in the air to reflect light off of. (Some work has been done with water, other liquids, even smoke.)
However, I have, in my magic shop, a curved mirrored bowl with a small hole at the top. Place an item in the bowl and a holographic image of it seems to be sitting on the top of that hole--in the air.
From any angle?
From any angle outside the bowl, yes. But it's not strictly a hologram, it's a focused reflection, and what you're looking at is the bottom of the bowl.
Posts: 3735 | Registered: Mar 2002
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The toy shop I work at sells that too, it's pretty convincing. I thought it was called a Miroscope, but I can't find it on the internet under that name.
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