New camera offers ultrafast imaging at a fraction of the normal cost

https://phys.org/news/2023-09-camera-ultrafast-imaging-fraction.html

by wglb • 3 years ago

124 42 3 years ago

$Preview of New camera offers ultrafast imaging at a fraction of the normal cost$ phys.org

billfruit• 3 years ago

Does it use compressed sensing?

sp3322• 3 years ago

No. It's a really fancy mirror.

hinkley2• 3 years ago

pointing at several different sensors, or relying on the speed of light to time shift arrival at the sensor? I still can't tell from the article, but any of those would be a neat trick.

hgomersall• 3 years ago

Without having read any more than can be gleaned from the article, it sounds like it's using similar principles. That is, the image is transformed into a domain (frequency) that is more amenable to rapidly capturing the necessary information quickly without time gating directly. It's not obvious to me what the setup is, but this type of approach is neat.

numpad0• 3 years ago

He realized that rapidly changing the tilt angle of periodic facets on a diffraction grating, which can generate several replicas of the incident light traveling in different directions, could present a way to sweep through different spatial positions to gate out frames at different time points.

Is this saying that light through a lenticular lens sheet comes out slightly early/late depending on angles, and the sheet could be used as an array of delay lines with different time constants?

foota3• 3 years ago

I don't think so, I think it's more like sweeping an image across multiple sensors over time using the grating (probably via one of the piezo optical effects?)

But I'm not familiar with your terminology, so maybe that's what you said :)

Edit: Ah, they're using a DMD. The paper is published here: https://opg.optica.org/optica/fulltext.cfm?uri=optica-10-9-1.... Iiuc when the DMD mirrors are switching between on and off you can get different diffraction patterns while they're shifting, and these different diffraction orders will move the image on the camera.

dylan6045• 3 years ago

how could light ever be early?

distract89013• 3 years ago

The speed of light isn't constant. Light travels slower in glass and water than in air. The difference in light speed in different materials is why refraction and lenses work. Additionally, light can bounce around inside a prism or a lens and take a longer path which takes more time.

tzs2• 3 years ago

Suppose you have two points, X and Y, each distance d from some origin O. At time 0, some light is emitted from O towards both X and Y. The earliest it can arrive at either of them is time d/c, where c is the speed of light in a vacuum.

If you want the light to arrive at different times you can either do something to make the paths different lengths, or to make the speed of light different on the two paths, or both. You can't make the speed faster than c on either of the paths but you can make it slower by making the light go through something with an index of refraction greater than 1.

Now suppose you've got some thing that you have built to process light, and you care about the differences in arrival time of the light to different parts of the thing. There's probably going to be some part of your thing that it makes the most sense to use as a reference, and then describe light arrival times elsewhere relative to that reference point.

There's usually no particular reason to pick as the reference the point on your thing that light first reaches. If you do indeed pick a reference that is not the earliest place of contact with the light, then you can have light arrive earlier at other parts of your thing.

imchillyb• 3 years ago

http://www.hajim.rochester.edu/optics/sites/boyd/assets/pdf/...

Fast and slow light. Read and be edified.

pyinstallwoes3• 3 years ago

There seems to be something to that in regards to fresnels lenses and meta materials.

beckerdo• 3 years ago

Photos or it didn't happen!

hinkley2• 3 years ago

The claim to have photos. They did not seem to have shared them :/

araes• 3 years ago

The full paper can be found here: https://opg.optica.org/optica/fulltext.cfm?uri=optica-10-9-1...

It has pictures of:

Fig. 3. Side-view observation of laser-induced breakdown in distilled water https://i.imgur.com/s4NeSmP.jpg

Fig. 4. Front-view imaging of cavitation dynamics https://i.imgur.com/GCyW6xY.jpg

Fig. 5. Imaging the laser ablation of single-layer onion cells https://i.imgur.com/K7H0uso.jpg

As well as setup and configuration

dekhn3• 3 years ago

"cuvette with carbonated drink"

xeonmc• 3 years ago

So basically it's like a CRT sweeping electron beams across the screen

h1fra• 3 years ago

4.8 million frames per second is wild. Currently the phantom can achieve I think 1.5M fps in black and white with a "postal stamp" resolution. I wonder what resolution this camera could output but I guess it's probably smaller than < 120px.

davidhyde• 3 years ago

They should probably have indicated how many frames they can capture too.

The team created a DRUM camera with a sequence depth of seven frames, meaning that it captures seven frames in each short movie.

Seems like their movies could possibly only be 7 frames in length so not really comparable to Phantom type cameras which can capture a lot more content.

Still, it’s great to see the mirror tech used in DLP projectors having other uses. Some 3D resin printers use it too but that’s still projection I guess. I think those dlp mirror chips are amazing and probably fascinating to hack around with.

h0l0cube2• 3 years ago

He realized that rapidly changing the tilt angle of periodic facets on a diffraction grating, which can generate several replicas of the incident light traveling in different directions, could present a way to sweep through different spatial positions to gate out frames at different time points.

My guess is the ‘sequence depth’ relates to the amount of diffraction gates. So perhaps all that’s needed is an ultrafast shutter to string together a long ‘movie’

xattt• 3 years ago

From Wikipedia:

1,750,000 frames per second at a resolution of 1280 x 32

It’s just a slit! This is wild it’s even possible.

credit_guy• 3 years ago

It's wild indeed. Maybe even wilder is that a camera capable of taking on million frames per second was developed in 1940. It was called the Repatronic camera [1],[2]. I can't provide a link, but I read in the book "Dark Sun" by Richard Rhodes that they had a 3.5 million frames per second camera when they detonated the first thermonuclear bomb, Ivy Mike, in 1952. I found in a different place that the guy who built this camera was a certain Berlyn Brixner. The wikipidia page for Berlyn Brixner [3] does not mention this detail, unfortunately.

[1] https://www.nnss.gov/docs/fact_sheets/DOENV_1136.pdf

[2] https://en.wikipedia.org/wiki/Rapatronic_camera

[3] https://en.wikipedia.org/wiki/Berlyn_Brixner

New camera offers ultrafast imaging at a fraction of the normal cost

Related Stories