How does Hologram work?

[nec208]

I know holograms make a 3D image like in the movie star wars.I know CNN make a hologram of reporter but this was not a true 3D hologram .

Does hologram use laser or light? How do they make a 3D hologram ? I hear it big fad and alot of scientist are workng on it.They say alot of people in CAD or avation use it when working on new things to find problems.

Also how does a hologram store data or process information?

 

[Shpaget]

If I remember correctly that hologram the CNN made wasn't at all a hologram. It was blue screen effect visible only to viewers and not to the ones in the studio. They were looking in the direction where the "hologram" would seem to be projected when viewing from the cameras position, but in fact they were watching a monitor which was outside the view.

It was just a cheap marketing trick. They should be clubbed to fine powder. :lol:

 

[nec208]

I thought it was a 2D image to look like 3D image like from projector being use?

A true 3D hologram would cost lots and lots of money.

 

[Shpaget]

Let me draw it...
You take a normal studio:

In another studio you place a guy in front of a blue screen:

You delete the blue background and copy/paste the guy to the first scene.

People in the first studio do not see the "hologram". It's an editing trick used every day in news, weather reports etc.
You don't really believe the weather man stands in front of a giant map with clouds and rain floating around, do you?
Exactly the same thing is used here.

 

[nec208]

What is the blue screen use for?

 

[MeteorWayne]

The whole blue (or green ) screen thing is unrelated to the hologram topic.

A simple google searh would explain holograms quite well.

A search on Blue Screen or Green Screen would explain the process of inserting images in video feeds. They are totally unrelated. Despite what CNN calls it.

 

[nec208]

I have not seen much explaining of 3D hologram has 5 years ago it was scfi and not possible .A scientist or engineer would laugh at you 5 years ago if you talk about a 3D hologram like in the movie star wars.

 

[Shpaget]

The whole blue (or green ) screen thing is unrelated to the hologram topic.

I agree, but this is the technique used by CNN to make their "hologram" which nec208 mentioned in his first post.
I just wanted to make it clear that it was not a hologram at all.

nec,
blue (or green) background is used to produce a difference in color of the background and the person in front of it so that the background can be easily deleted (you just say to your computer to replace whatever is blue with transparent "color") and replaced with some other picture or video.

 

[CalliArcale]

CNN is calling that a hologram? As if we needed more evidence that they're idiots. I mean, the technique isn't even new; meteorologists in particular have been making heavy use of it for years, and it's been used in prerecorded film and television for even longer. Other, older names are "chromakey" (which is a brand name, IIRC) and "color separation overlay" or "CSO". "Bluescreen" is also a common name for it, sometimes even when the backdrop isn't blue. (Green is actually more common, though strictly speaking any color can be used.) Basically, a computer creates a mask in the video signal by selecting all the bits of Image 2 which are the target color (or within a certain range of the target color) and removing them, and then overlays the masked image over the other image. In days gone by, it would be very obvious; you'd see a little halo around the person. But as computing power has increased, this technique has improved as well. With digital signals, it's even better, and of course all kinds of digital effects can be applied to one or both images, even in a live feed.

A true hologram is a flat image which has recorded three-dimensional data. These are the images that seem to shift as you move side to side. Unlike a stereogram or anaglyph, in which two pictures are presented and you use special eyewear to feed one image into one eye and the other image into the other eye, a true hologram actually captures the angles of various light beams striking the film, and this makes it seem like a three-dimensional photograph. It's not really a photograph, although the film is photosensitive and much of the technology is the same. It all works through the interference of two different sets of light -- light reflected off of the target (usually a small sculpture or object to be scanned) and a reference beam, which is recorded in the film emulsion in such a way that shining normal light on the object will stimulate the light to be reproduced. It's all very clever. I once had the opportunity to make a hologram; it was quite a memorable experience for a young girl.

 

[nec208]

Here is a true hologram http://www.youtube.com/watch?v=-k5nt541SE0

http://www.youtube.com/watch?v=FF1vFTQO ... re=related

 

[Shpaget]

I would prefer to see a stationary image and camera rotating around it like in the second video.
In any case, nice vids.

 

[nec208]

What is wrong with the first one?

 

[Shpaget]

I'm not saying anything is wrong with it. I'm saying you're not able to see it in it's full.
I would prefer to see something like a complex stationary object projected and camera turning around it.
I can't shake off the feeling that it is actually a 2D image of an object spinning around (just like you can view it on your regular computer monitor) and not a 3D image/object floating in air.
That's the impression I get, especially from the part with the car and some buildings in the background.