[HN Gopher] U of T computational imaging researchers harness AI ...
___________________________________________________________________
U of T computational imaging researchers harness AI to fly with
light in motion
Author : croes
Score : 44 points
Date : 2024-11-20 13:14 UTC (9 hours ago)
(HTM) web link (web.cs.toronto.edu)
(TXT) w3m dump (web.cs.toronto.edu)
| amelius wrote:
| Hmm, if AI is involved I'm always wondering whether what I see is
| realistic or not.
| juancn wrote:
| In this case, they're basically using a neural network to
| approximate a really tricky high dimensional function from a
| lot of measurements from a scene, and use it to interpolate
| values.
|
| Think of it as "fancy (non)linear regression" or something like
| that.
|
| It's quite clever.
| dylan604 wrote:
| I'm now wanting to set up my magic bullet rig to try this!
|
| Just thinking about consumer equipment, being able to shutter
| release and fire a laser "burst" precisely enough would be a
| challenge. If the shutter release is wired, does the time for
| the signal to travel down the wire + the mechanics of the
| shutter need to be compensated for the time of flight of the
| "photon"? I could see this being one of those YouTube
| channels with someone doing this in their garage.
|
| All of that to say that the accuracy of what they've done is
| impressive
| godelski wrote:
| Your suspicion is warranted, but it really depends on what "AI"
| is being used (I'd rather call it ML. As a ML researcher
| myself, and who publicly criticizes LLMs[0]).
|
| The reasoning for this is that in essence, ML is curve fitting
| data from high "polynomial" functions (approximately accurate).
| But there are many things like density estimators which are
| very good in statistical settings where you cannot access the
| density function directly (called "intractable") and so all you
| can deal with is samples (e.g. you can sample examples of human
| faces, but we have no mathematical equation to describe all
| variations and in what likelihood). This is not too different
| from Monte Carlo Sampling and is often used in variational
| inference. When you are doing density estimation you can have a
| lot more confidence in your results as you can actually do
| things like building proper confidence intervals and you can
| test likelihood (how well does your model explain the data).
|
| So yeah, keep the skepticism up. There's a lot of snake-oil in
| ML and these days it is probably good to default to that
| position. Especially since a lot of ML people are not well
| versed in math and there's a growing sentiment of not needing
| math (you'll even find that common around here. It is a
| reliance upon empirical results and not understanding "Elephant
| fitting"). FWIW here they're using NeRF and it looks like they
| are using it to tune parameters of their physical model. I'd
| have to take a deeper look but at a quick glance I'd let down
| my guard a bit.
|
| [0] Worth noting that "AI" used to be the typical signal that
| some thing was snake oil. Now everything is called AI. I'll
| leave it to the reader to determine if this is still a strong
| signal or not.
| Sporktacular wrote:
| Why does the refraction appear instantly below the bottle rather
| than taking time for the light to propagate there?
| moralestapia wrote:
| Great observation, however I do feel like it's not instant but
| feels like it's following behind the main pulse, so should be
| accurate.
| donbox wrote:
| To me it felt like its instant in the downwards direction
| tablatom wrote:
| I thought I could only see photons that hit my retina :)
| sxp wrote:
| https://arxiv.org/pdf/2404.06493 is the paper. If I'm
| understanding it correctly, the camera isn't actually capturing a
| pulse of light. Instead, it's recording single pixels from a
| 10MHz series of pulses using a single pixel camera that rotates
| around the object. Then uses this time-series of data to render a
| video of a "single" virtual pulse via a NeRF.
|
| The "AI" in the title appears to be click bait since the paper
| doesn't mention AI, and a NeRF isn't really AI in the colloquial
| sense even though it uses a DNN.
| variadix wrote:
| If you have something periodic in time you can get high time
| resolution of what looks like a single event by taking multiple
| periodic captures with tiny phase offsets. It's a neat
| capability
| dtgriscom wrote:
| Periodic strobe light.
| dylan604 wrote:
| Did Coca-Cola sponser/fund this study? Why the need for the label
| still being visible? Seems like you'd want to not obstruct the
| view behind the label, you know, for science. There's zero
| purpose for having a bottle with any label. The shape of the
| bottle is part of their trade mark, so it would be obvious
| anyways.
|
| Apparently, I'm really sick of constant bombardment from
| corporate branding.
| barbazoo wrote:
| Puzzling, I can see why a pop bottle, due to its shape, would
| make this more fun to look at than say a boring cylinder but
| why the free advertisement by leaving the label on?
|
| It's not even that it's cola inside, obviously
|
| > We use a collimated beam to illuminate a Coca-Cola bottle
| filled with water and a small amount of milk
| astrange wrote:
| If there wasn't a label on this bottle it'd be so plain looking
| that you'd think it was a 3D render and not real.
|
| I think you should just remember you live in a society and
| societies contain mass market brands that aren't going
| anywhere.
|
| In particular with sodas, most of the indie ones are worse for
| you. Coke at least makes Coke Zero, all the indie ones with
| 2010-hipster branding have 60g sugar in each can.
| soulofmischief wrote:
| For those curious, here is prior art from 12 years ago, capturing
| light in a coke bottle with a single streak camera.
|
| https://www.youtube.com/watch?v=EtsXgODHMWk
|
| https://web.media.mit.edu/~raskar/trillionfps/
|
| I remember when this dropped and where I was when I watched it
| and read the paper. One of the coolest things I'd ever seen.
|
| This seems like a great extension of the work. I'm okay with
| trading accuracy for crude usefulness as a model. Making this
| interactive and putting it in the hands of curious minds is the
| next step.
___________________________________________________________________
(page generated 2024-11-20 23:01 UTC)