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Study produces 3D images that float (byu.edu)
160 points by snr on Jan 26, 2018 | hide | past | favorite | 56 comments



Another method is to use a high-powered pulsed laser to create little balls of plasma in mid-air: https://www.popsci.com/secret-interactive-holograms-plasma-a...


Wow, the plasma-balls one's from 2015!


I feel like I've seen reports of research demonstration with near future commercial possibility in this field every couple years since sometime in the mid-1990s.


That’s the reporting. Ideally researchers should just say “we did this.” But then they need continued funding so they like to say “we did this and we believe with more research the commercial possibilities are promising.” And then reporters hear this all and say “the Star Wars display is here now, and soon you’ll have Princess Leia in your living room.”

Honestly I feel like the best solution is just to train everyone critical thinking skills but I guess in practice that doesn’t seem to happen.


There are lots of ways to make star wars holograms that are much more accessible than this. With our new depth sensors and some other really stupid tricks you can achieve that. There's a reason Apple is hiring like crazy for AR designers. We are pretty closer to in that future.

If you're looking for the bleeding edge of what's here now, RED[1] the camera company is putting out a hologram cell phone probably like next month I guess with a hologram display from a company literally called leia[2].

[1]https://www.theverge.com/circuitbreaker/2017/9/8/16272838/re...

[2]http://www.leiadisplay.com/


From the FAQ:

> Is LEIA a hologram?

> Leia makes it possible to project an image in the air – an image through which you can put your hand or walk but it's not a 3D projection. The image is flat and thus does not meet the criteria of the hologram definition.

So what is it?


When you really get into spatial imaging, splitting hairs on definition is really important. To the layman, it's basically what you think of as a hologram. Holography is a photographic record of a light field. Leia might be more accurately described as a spatialized parallax display. With a light field you would be able to infinitely change your depth focus to any item in the volume because the entire light field is captured.


This is really clever, from a design perspective. I mean, projecting onto a moving particle is a really innovative idea. But scientifically, what I find the most surprising, is that a laser trap can move a particle around at sufficient speeds, outside a vacuum, without losing it. Impressive! I had no idea that was possible. Anyone know what speed or frequency of movement it can achieve?


Judging from my experience with other well-polished PR pieces from universities, I would expect only the "oscillating above the finger tips" parts to be real time. The more advanced examples were only shown statically and thus were probably like long-shutter images.


Projecting on a moving particle isn't quite new. A quick search reveal that there have been projections on falling water droplets since at least 2010. There are also plenty of stroboscopic experiments on water drops which make them fall upwards.

I think having a controllable particle is a nice-feat but probably is overkill for 3D displays, you only need to know where the particles are so you can use them as a screen.

Although the 2010 paper project on layers of waterfalls, it's easy to imagine a 2d water droplet grid where you watch the droplets form and drop with a hi-speed camera and with a video projector you then project the right pixel at the right time so that light ray intersect water droplet. You can even try this today at home with a shower jet and a pico projector, and see beautiful clouds of red green blue rays.

It's probably a fun engineering project to get the right combination of liquid properties, size of droplets, frequencies, video bandwidth to obtain stunning results.


I've seen this in operation and am acquainted with the researchers. I may be able to attempt to answer some questions about it.


Cool stuff! I'm curious what limitations there are on how fast the particle can move. Is it theoretically possible to move a single particle fast enough to render complex shapes in real time, or will you need many particles for that?


Would it be possible to suspend these kinds of particles using a standing wave of ultrasound ? Perhaps something similar to https://www.researchgate.net/publication/265401333_Cell_and_... and then project the laser on them.


Sorry, I'm not qualified to give a good answer.

I would guess that the relatively long wavelength of ultrasound could potentially cause resolution issues.


Not only resolution issues, but accuracy issues as well.

I doubt ultrasound can provide the same fidelity as a highly-tuned laser high-frequency laser beam when it comes to keeping something in one place.


Thanks for both your answers. Though I was also thinking perhaps you could just suspend the particles in mid-air, and use the movable prism in a laser projector to actually "render" the projection (thus not needing to move them at at a high frame rate or at all). However I guess, you probably do need to move the particles as well to be able to make it a 3D volumetric shape in space (seen from all angles etc).


How does this compare with the plasma dots approach? https://www.popsci.com/secret-interactive-holograms-plasma-a...

(Thanks @iliis for posting about this research)


I'm not very familiar with the plasma dots approach, but from a cursory look it appears that it is not capable of RGB. On the other hand, there is nothing that can fall out of confinement so the display is probably more stable.

That page says the femtosecond plasma display is pretty safe. This display was - and I believe still is, though I could be wrong - using a UV laser for confinement, which is sorta scary.


Awesome achievement! This really looks like a viable way of true floating 3D-images.

Can you levitate multiple particles at the same time? How fast are they moving? How sensitivie is it to disturbances in the air?


> Can you levitate multiple particles at the same time?

Yes, but their device currently is only capable of levitating a single particle. With the current approach, the device would need one laser for confining each particle. The lasers used for RGB could potentially be multiplexed between particles, but this is less likely to work for the confinement due to the instability of the trap.

> How fast are they moving?

Pretty slow. All the "big" images (Leia, grad student, etc) are long-exposure. You can see the particle moving in real-time at about 0:50. In the videos, you can see the device can almost do real-time persistence of vision for volumes substantially smaller than a fingertip.

> How sensitive is it to disturbances in the air?

As I mentioned above, the confinement is weak and the trap is pretty unstable. Its possible that they have improved the longevity of the trap in the last few months, but when doing long-exposure the device is surrounded by a heavy cloth barrier to block both external light and air movement.


I'm guessing it's very sensitive to air flow since the photon "shells" are literally trapping the particles.


Where does the cellulose come from? Is it just ambient particles or are they emitted from the machine? Where does it go?


The cellulose comes from the black liquor on a spoon (see 0:46 in the video). The put the spoon at the focus of the laser and with luck some particles get confined. After the trap is lost, the particle just sort of drifts away in the air, since they are only tens of microns.


How powerful are the lasers?

What kind of safety equipment is required to view it?


For now, they created a single pixel by trapping one particle (not sure what it's made of) and beaming different colors on it.

Depending on when they managed to trap two particles, we can start applying Moore's law and double it every so often.


It sounds to me like they move the particle around and use persistence of vision to make an image.


Kind of like CTR displays but in 3D.


That was the most remarkable thing to me - that's just one pixel moving around. Imagine if we had two, or four, or eight? Pretty quickly we get amazing and complex results.


> Humans cannot discern images at rates faster than 10 per second

If the PCMR folks already hate everyone saying the human eye sees at 25FPS, imagine how they'd react to that!


I have to admit my first reaction to that was "and yet 60fps is apparently too slow for VR".

But I think they might have been talking about how long the trail would persist for in our vision, making it appear as one object when it goes in circles. Not how quickly you can flash images in front of us before we won't be able to see them. I'm not sure if it's true in that case.


VR is not about image perception, but image reaction. The important part is how long it takes from you providing input to the input reaction being perceived by you. The latency between that. And given a sufficiently huge sample size (interacting with VR is many minutes of nothing but samples) a human can very easily discern this latency.


I find it interesting that people with such a large variety of world views (Mormons, Christians, Muslims, Buddhists, atheists, etc.) can all produce groundbreaking advances in science, math, and engineering.

Pick any two of those aforementioned groups, and you'll find plenty of members from one who consider the other's members to have unfathomably bad reasoning and common-sense skills. And yet, somehow, some members of all those groups bear wonderful intellectual fruit.


Maybe because most questions about life are 'why?' questions and not 'how?' questions.


Minus, say, "how did we get here" or "how should we behave?"

Or another way to look at it, we could reduce almost all questions, in science or religion, to something like "what is the nature of this stuff around me?"

A subpart, "how can I interact with the stuff?" A subpart of that question, in turn, is "what are the consequences of those interactions?"

Sometimes the stuff around you is carbon. You can burn it or build things with it. If you breathe enough of it in certain forms, you might suffocate.

Sometimes the stuff around you is other people. You can help them or hurt them in a near endless variety of ways. The consequences are complex but it's generally better to not be a dick, for a variety of reasons.

Maybe the stuff around you is... all of reality? Which may or may not be controlled by a unimaginably powerful law giver. Maybe not, but if so, that would certainly affect the consequences of a lot of actions, so it would be worth trying to work out how that system worked if that was the deal.

To be clear, I'm not arguing for Pascal's wager here, I'm just needling the idea of non overlapping magisteria.

Isn't it all just, "How does reality work?"


I hadn't heard of non overlapping magisteria (NOMA) before.

My immediate thought was that if you assume the 'teaching domains' of science and religion do not overlap at all, then the domain of religion is vanishingly small.

If you accept that science covers (at least) all observable things, and also hold the idea of NOMA, then religion must never deal with anything observable. The teaching domain of the unobservable seems like it would be near non-existent.

Alternately, let's start from the position that a supernatural power exists and cares about what we do. Why would we be interested in that? We would be interested if that supernatural power has the ability to affect our lives/the world we live in, or will affect our lives after we die/some other aspect of some supernatural world beyond this one.

If the power can affect this world, we should be able to observe that interaction. If it is literally impossible to measure any effect, it is the same as if the power is not interacting with the world at all. Which is to say, if the power interacts with the world, then those interactions fall under the domain of science.

If the power does not interact with the world, then we can only be interested in what effect our actions, choices, and beliefs will have outside this world, on the supernatural or afterlife. The thing is, we have no way of knowing what that would be, because communicating any of that information to us would count as interacting with the world.

Thus, anyone claiming that something should or shouldn't be believed or done, for religious reasons, is either making a testable claim or claiming something which has no reason to be believed.

If the magesteria of science and religion truly are non overlapping, it seems that religion's must necessarily be very very small.


The inventors of the television and of stereo sound both were of the Mormon faith.


I'm guessing by "people with such a large variety of world views" you mean "diverse groups with varying world views". But even if not, you might be surprised to find how simple these religious frameworks are at their core, and how much they really do allow a variety of world views within a single religion. There is plenty of surface area, so to speak, within something like a world religion, to which can be attached any amount of science. Science is of course just human psychology with certain conditions fuzzily applied, so for example, when adding religion into the mix, it helps to look at science as a convergence of modeling (soft sci) and measuring (hard sci).

I haven't been a Muslim or a Buddhist, but I was a Mormon missionary who taught Buddhists of many sects, plus South American Catholics, European atheists, Muslims, Raelians, and your odd Yakuza while I lived in Japan.

I was taught to respect these people for what they had already learned and experienced, and to teach them a simple, elegant model of my belief system. In studying that model I realized that I hold and have the responsibility to shape, apply, and evaluate multiple models of my religion through my own life experience. This becomes an ever-evolving science that is in principle one and the same with the more technological science posted here. There are deeper qualitative questions and experiential aspects and anecdotes that are really more like fractals than questions, open to broad and deep exploration. But those elegant models, the simple ones--right in there you have a huge amount of religious people who really don't differ much from your complete-opposite anecdotal scientist in the important ways.

I could go right now and google reasons why Mormons and science don't mix, or I could go out and find a Mormon who would argue with most any scientist (come to think of it, my Mom is a good one!), but the boundaries there are in the end just different from my own and I find there's absolutely room for that. I hold my own models lightly, and compare them with others' from time to time. But--and I doubt I'm some freak religious exception here--nobody is dictating my models and their composition / combination to me. I act in many ways in respect to my church like a robot (Sunday? Church!), not because I have to, but because in my mind, the overall experiment is yielding good results and I'll change variables as I need to when I examine them. I got the feeling that others in other religions act and feel basically the same way. As I mold my models I think of myself as a type of scientist, and hope any scientist would consider the study of religion from a scientific view (model all the time, measure what you can) as an absolute (and hopefully enjoyable) mandate.

The wonderful intellectual fruit you speak of is something I experienced first hand when I was a BYU student. As a teenager I was told how wrong evolution was by my dad (an extremely educated man himself with multiple degrees), heard how certain it was from my sunday school teacher (a respected surgeon), and then I went off to my BYU biology class and was immediately taught about talk.origins and told "hey if you guys (freshmen) don't believe in evolution that's fine, but at least educate yourself". This was a huge faith-strengthener to me; a diversity of models is not only OK but developing one's own educated models was seen as wisdom in a nutshell.


What a bizarre sort of bigotry to spout.


> What a bizarre sort of bigotry to spout.

I'm not sure how you'd get that from my original comment. But rereading it today, I realize I wasn't very clear. I apologise for that. Let me restate it more explicitly:

1. To be done well, science and engineering require careful thought and, to a certain extent, sound reasoning.

2. Some people holding world view "A" consider the holding of world view "B" to be intellectually indefensible, for many values of "A" and "B".

3. And yet we have plenty of empirical evidence that good science and engineering work is being done across all of those world-view-holding groups.

As far as why this particular article made me thing of this issue, it's because Mormons are sometimes ridiculed in (at least) U.S. popular culture for holding an intellectually indefensible world view. E.g., [0].

[0] https://en.wikipedia.org/wiki/All_About_Mormons


Must every discussion devolve into identity politics these days?


HN title: "Holograms are here"

Actual title: "Better than a hologram: BYU study produces 3D images that float in 'thin air'"

Article text: "First things, first, Smalley says. The image of Princess Leia is not what people think it is: It’s not a hologram."

Can we not editorialize and/or get the titles completely wrong?


Yes, that title broke the HN guidelines: https://news.ycombinator.com/newsguidelines.html. We've replaced it with the article title, or rather a less baity substring of it.


It's actually a hologram - which is by definition a 3D image. I contend that my original title is appropriate. Holograms ARE volumetric displays. I can see why the researcher wouldn't want to call it that - claim you invented something better than science fiction = instant media coverage.

hol·o·gram noun A three-dimensional image formed by the interference of light beams from a laser or other coherent light source.


As indicated by your definition, the 3d-effect of a hologram arises from interference of a coherent light source. In the display that is shown in the video, the 3d-effect arises from light-emission (scattering) of a point source that moves around. The light from the point source need not be coherent for this display to work! Therefore, the term "hologram" seems inappropriate.

I have never seen a hologram that is also a volumetric display. To me, this would be the holy grail of hologramming, since you could use interference for occlusion effects.


Kind of funny title given that the speaker says several times in video that it's NOT a hologram


Nonetheless, everybody calls the displays in Star Wars "holograms". Smalley notes this, and the title is using the word in this colloquial sense. There is an unfortunate disconnect between the technical and colloquial meanings of "hologram".


First things, first, Smalley says. The image of Princess Leia is not what people think it is: It’s not a hologram.

Oh well.


https://news.ycombinator.com/item?id=16225854

47+ points

Actual title of this submit was "Better than a hologram: BYU study produces 3D images that float in 'thin air'"


"The future won't be the future without a Princess Leia projector".

Love.


Great another medium from which failed reality stars can convince an increasingly stupid public to vote for.

Edit: This is funny, no one was a sense of humor. Just imagine Donald Trump's holographic head spinning slowly while he gives the state of the union. That's the future.


Please don't post unsubstantive comments or add political flamebait into HN threads.

https://news.ycombinator.com/newsguidelines.html

Edit: you've posted a ton of unsubstantive comments and we've asked you before to stop, so would you please stop? We're hoping for higher discussion quality here.


I guess I could've framed it differently, but I think it's pretty high quality stuff idk.


> Edit: This is funny

Perhaps (I disagree, but its subjective), but also ungrammatical and substance free. The latter is probably what HN doesn't like.

This isn't Slashdot, and +1 Funny isn't, in general, a thing.


>This is funny

You aren't the arbiter of your own jokes, as evidenced.


I guess there's a wider discussion about why need more and better display technology without a noticeable improvement in quality of life, but idk.


Practical volumetric display could improve lots of fields, including medicine.

(Admittedly, VR/AR gets you most of the benefits of that, but its also clumsier.)




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