Okay it's not prectical
but it's a step in the right direction. I'm not getting my hopes up but I want to be able to shag fit birds in holosuites when I'm a pensioner.
Scientists in Japan have built a computer capable of generating holographic images from three-dimensional models composed of up to a million points. But don't expect holographic messages from alluring princesses any time soon: the machine can only render million-point holograms at a single frame every second. Drop the …
But then the hologram is little better current 3-d technology, in that it's only designed to be viewed from one angle. (In fact, when you add in the low frame rate, incredibly high processing power requirement, and lack of color*, it's pretty much pointless. You can get much better results with stereoscopics on a midrange video card.)
The major benefit of true holography is the ability to view it from any angle. So if they don't have that, they don't have jack.
* That's right: I said "color". I don't use unnecessary vowels. Bring on the Britard backlash!
Yeh man, think about it, you're giving the big Death Star project presentation to the board, they ask you why there's a trench which directly leads to a vent which is the one and only weakness in the entire thing and you can't show them the chicken wire mesh you've placed over it because all you can see is the other side of the hologram over/underlayed.
Sheesh, some people!
"There's nothing in holography that dictates that just because you *can* recreate all of an object in order to view it from any angle, that you have to see all of the object at once."
That is true, but if I am looking at the front and you are looking at the back, I should see all the front and you should see all the back...
Nah, I'm with Bob. If it has to do occlusion calculations, it's not a feckin hologram, because you can't move freely around it and view it from all angles. Anything that only works when your eyes are at one fixed position in relation to the light source is some kind of stereoscopic image, not a proper hologram. Did you read the paper? Take a look at Fig 2c. It's some kind of peephole through which you can squint to see a vaguely solid-looking image. Load of old rubbish.
As the caption said, it's not Princess Leia.
Surely you meant...
"But then tha hologram s littl bettr currnt 3-d technology, n that it's only designd to b vewd from won ngl. (In fact, when yu add n tha low fram rat, ncredibly high processng powr requirmnt, nd lack f colr*, it's pretty much pointlss. You cn get much bettr results with stereoscopics on a midrang video card.)
Tha majr benefit f tru holography s tha ability to vew it from ny ngle. So f they don't hav that, they don't hav jack.
* That's right: I sed "color". I don't us unnecessry vowls. Brng on tha Britard backlash!"
(Want the consonants doing too? ;)
If what you are saying is that you are a USAian, I'd suggest that every vowel or consonant you ever use is unnecessary. I'd suggest that whimsically and respectfully of course.
Have to say though, any word ending in 'tard' tends to make me feel slightly sick, although I can't criticise you much for that because judging by the Reg comments section most Brits find it acceptable and even 'funny'(!?) to suffix everything with tard nowadays. When I grew up 'retard' was a verb anyway. And don't get me started on FAIL, 'Paris because', 'Mine's the one with the' etc etc...oops I just sicked on myself - what was the article about again?....
Say you have a solid holographic cube, no matter where someone stands they won't be able to see the insides of it, therefore you only need to render the outward facing parts. Kind of like a holographic BSP tree I'd expect. It's got nothing to do with occluding different parts based on which angle you're viewing it from, but occluding parts that can't be viewed from ANY angle. Imagine an animation where a horse is going through a tunnel, when it's in the tunnel you'll be able to see some of it from different angles, but not all of it, and you can calculate which parts are never visible.
Wow, I didn't know that off the shelf components already had a high enought resolution for that. Considering that it should surely be possible to generate holographic television now. All you need is a image sensor the size of that LCD to record the RL interference pattern, then store it on your average HDTV video tape recorder and play it back. All you need is a studio illuminated by coherent laser light.
can someone explain this to me, or are we really looking at a grasshopper sized image?
"An Aurora Systems ASI6201 was used as the reflective LCD. The size of the LCD is
M = 1,920×1, 080, and the dot pitch is p = 6.4μm. The distance between the LCD and the
reconstruction image is 1 m, and the viewing angle is approximately 5◦.
http://www.aurora-sys.com/products01.html looks like a .55" diagonal
Also in the PDF, "The size of the reconstructions is approximately 5 cm × 5 cm× 5 cm." So do I walk in the room and see a grasshopper sized "holograph" somewhere, or do I need to go stand in front of some lense and look in at the little fella.
There's a lot of crap being posted in these comments based on misunderstanding of what's going on here. This is a form of reflection hologram with computer generated interference fringes.
A normal reflection hologram could be created with a single expanded beam by illuminating a film with an object behind it. Light striking the object would reflect back and interfere with light striking the film. The film would record an interference pattern - a set of light and dark fringes.
This normal hologram could be played back by illuminating it with an expanded beam once again. The beam would interfere with the fringes on the film and the result would be the appearance of the original object. Looking around the hologram you would see the object as it appeared because that's simply what was there. Parts which were occluded from certain angles would be occluded in the hologram from those same angles because the reflected light, by definition, never made it from those parts to contribute to the interference fringes at that point on the film.
In this project the playback method is the same. However instead of the fringes coming from a pattern recorded on a piece of film, they come from a reflective LCD. The fringe pattern on the LCD is being generated by the purpose built compute cluster. Thus there is no real object to display - instead it is a model of an object, in this case a model constructed from up to 1 million points.
This is where the issue of occlusion comes in, because the model contains all the points used to define the object, but it is up to the computer to determine which points should be visible from a particular angle as it calculates the interference fringes that would be present at that angle. At the moment the system does not make that determination, and hence the playback shows the entire model including surfaces which would be hidden from certain angles if the object was real.
The intention is to augment the capability of the cluster such that it is able to make that determination, hence adjusting the computed fringe pattern and thus correcting the appearance of the modelled object.
Why vowels? What have you Merkins got against them? (I am assuming you are a Merkin as you spell like one, and used the word 'Britard')
You said, and I quote "I don't use unnecessary vowels." Yet in the preceding sentence you also said, and again, I quote "That's right: I said "color"."
So by your own logic, you used 'said' instead of 'sed' thus using an 'unecessary' vowel. You also used the word 'right' instead of 'ryt' or 'rite' or 'rit' or whatever horribly confusing so called 'simpe' phonetics will give you. So in Merca it's ok to hate vowels, but not consonants? Did consonants win the War of Indepedance or something? And what about dipthongs? Do u hat dem tu? C how hard lif is wifowt 'unesesari' vowels an dipfongs?
What do you do, just make up logic on a whim? Or just fail to think rationally?
Consider thyself flamed by many coloured flames.
There seems to be quite a bit of confusion here about what the word "occlusion" means - esp. relating to CGI.
Every object model has depth - even standard 2D gaming objects. This is because objects are manuipulated as 3 dimensional objects in "world space" inside the computer and then transposed into a set of 2 dimensional co-ordinates for display on screen et al.
Occlusion is always required in CGI (and holograms) because in the same way I can't see the back of your head when I'm looking at the front in the real world, neither would I want to in CGI.
Therefore depth calulations are always needed to firgure out the viewing angle to the faces of the object that can be seen, and thus "occlude" the faces that can't.
We've got the standard problems with a new technology here. Hologram technology is theoretically better than stereoscopic technology, but because it's at such an early stage of development, the advantages are not obvious, and it appears worse than the old technology. The viewing angle might be restricted, but that is not a fundamental feature of hologram technology, whereas it is with stereoscopic viewing.
This is star-wars technology. I was amazed that it was even possible to create any kind of interference pattern from an LCD display. Certainly, the technolgy to create a display that could render a the full interference pattern for a full TV picture must be a long way off, but it is great that someone is researching this stuff.
Occlusion in a hologram is going to be a huge issue compared to regular (flat) 3D, since you can't cull an object's hidden geometry based on the viewing angle (of the observer as opposed to the camera).
So it's just another projected camera trick to give depth. I want to see genuine "walk-around" holograms. This stuff is boring.
The wave length of red light is around 700nm. A 1920 by 1080 LCD for interference patten would be 1.3mm by 0.76mm.
I would imagine you would have to ray trace the light from a virtual laser illuminating the model to the virtual screen pixel, measuring the length of the trace in wavelengths and adding to all the other traces hitting that pixel.
With such a tiny screen, you would need a magnifying glass to see the hologram.
I would imagine it would be easier to use UV photo-active or electro-active film/glass written with a UV or electron beam and illuminated with a red laser. A 5cm cube would require 71,429 x 71,429 pixels or 5G pixels.
Ah, but if you're only aiming or 5 degrees of viewing angle, then your Nyquist wavenumber gets multiplied by sin(5 deg), I guess. With a factor of two in there for good measure, I make that something like 700nm / (2 sin(5 deg)), or about 4 microns per pixel. Still quite small, though. It probably doesn't work like that though, or there's be all sorts of diffraction problems.
This is probably why holographic television requires more than just a bunch of us semi-informed commenters to invent it.
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