Imaging at a trillion frames per second
-
0:01 - 0:07Doc Edgerton inspired us
with awe and curiosity -
0:07 - 0:12with this photo of a bullet
piercing through an apple, -
0:12 - 0:16and exposure just a millionth of a second.
-
0:18 - 0:25But now, 50 years later,
we can go a million times faster -
0:25 - 0:29and see the world
not at a million or a billion, -
0:29 - 0:32but one trillion frames per second.
-
0:34 - 0:38I present to you
a new type of photography, -
0:38 - 0:40femto-photography,
-
0:40 - 0:44a new imaging technique so fast
-
0:44 - 0:48that it can create slow motion
videos of light in motion. -
0:49 - 0:54And with that, we can create cameras
that can look around corners, -
0:54 - 0:56beyond line of sight,
-
0:56 - 1:01or see inside our body without an x-ray,
-
1:01 - 1:05and really challenge
what we mean by a camera. -
1:06 - 1:10Now if I take a laser pointer
and turn it on and off -
1:10 - 1:12in one trillionth of a second --
-
1:12 - 1:15which is several femtoseconds --
-
1:15 - 1:19I'll create a packet of photons
barely a millimeter wide. -
1:20 - 1:23And that packet of photons, that bullet,
-
1:23 - 1:25will travel at the speed of light,
-
1:25 - 1:29and again, a million times faster
than an ordinary bullet. -
1:30 - 1:34Now, if you take that bullet
and take this packet of photons -
1:34 - 1:37and fire into this bottle,
-
1:38 - 1:41how will those photons
shatter into this bottle? -
1:42 - 1:44How does light look in slow motion?
-
1:45 - 1:48[Light in Slow Motion ...
10 Billion x Slow] -
2:06 - 2:08Now, the whole event --
-
2:08 - 2:15(Applause)
-
2:15 - 2:18Now remember, the whole event
is effectively taking place -
2:18 - 2:20in less than a nanosecond --
-
2:20 - 2:22that's how much time
it takes for light to travel. -
2:22 - 2:27But I'm slowing down in this video
by a factor of 10 billion, -
2:27 - 2:29so you can see the light in motion.
-
2:30 - 2:31(Laughter)
-
2:31 - 2:33But Coca-Cola did not
sponsor this research. -
2:33 - 2:35(Laughter)
-
2:35 - 2:37Now, there's a lot going on in this movie,
-
2:37 - 2:40so let me break this down
and show you what's going on. -
2:40 - 2:43So the pulse enters
the bottle, our bullet, -
2:43 - 2:45with a packet of photons
that start traveling through -
2:45 - 2:47and that start scattering inside.
-
2:47 - 2:49Some of the light leaks,
goes on the table, -
2:49 - 2:52and you start seeing
these ripples of waves. -
2:52 - 2:55Many of the photons
eventually reach the cap -
2:55 - 2:58and then they explode
in various directions. -
2:58 - 3:00As you can see, there's a bubble of air
-
3:00 - 3:01and it's bouncing around inside.
-
3:01 - 3:04Meanwhile, the ripples
are traveling on the table, -
3:04 - 3:06and because of the reflections at the top,
-
3:06 - 3:10you see at the back of the bottle,
after several frames, -
3:10 - 3:11the reflections are focused.
-
3:13 - 3:19Now, if you take an ordinary bullet
-
3:19 - 3:22and let it go the same distance
and slow down the video -- -
3:22 - 3:24again, by a factor of 10 billion --
-
3:24 - 3:28do you know how long you'll have to sit
here to watch that movie? -
3:28 - 3:30(Laughter)
-
3:30 - 3:33A day, a week? Actually, a whole year.
-
3:34 - 3:37It'll be a very boring movie --
-
3:37 - 3:38(Laughter)
-
3:38 - 3:41of a slow, ordinary bullet in motion.
-
3:43 - 3:46And what about some
still-life photography? -
3:53 - 3:58You can watch the ripples,
again, washing over the table, -
3:58 - 4:01the tomato and the wall in the back.
-
4:01 - 4:04It's like throwing a stone
in a pond of water. -
4:07 - 4:11I thought: this is how
nature paints a photo, -
4:11 - 4:14one femto frame at a time,
-
4:14 - 4:18but of course our eye sees
an integral composite. -
4:20 - 4:22But if you look at this tomato
one more time, -
4:22 - 4:25you will notice, as the light
washes over the tomato, -
4:25 - 4:27it continues to glow.
-
4:27 - 4:29It doesn't become dark. Why is that?
-
4:29 - 4:31Because the tomato is actually ripe,
-
4:31 - 4:33and the light is bouncing
around inside the tomato, -
4:33 - 4:37and it comes out after several
trillionths of a second. -
4:38 - 4:42So in the future, when this femto-camera
is in your camera phone, -
4:42 - 4:44you might be able to go to a supermarket
-
4:44 - 4:47and check if the fruit is ripe
without actually touching it. -
4:47 - 4:49(Laughter)
-
4:49 - 4:53So how did my team at MIT
create this camera? -
4:54 - 4:56Now, as photographers, you know,
-
4:56 - 5:00if you take a short exposure photo,
you get very little light. -
5:00 - 5:03But we're going to go a billion times
faster than your shortest exposure, -
5:03 - 5:05so you're going to get hardly any light.
-
5:05 - 5:07So what we do is we send that bullet --
-
5:07 - 5:10that packet of photons --
millions of times, -
5:10 - 5:13and record again and again
with very clever synchronization, -
5:13 - 5:15and from the gigabytes of data,
-
5:15 - 5:17we computationally weave together
-
5:17 - 5:20to create those femto-videos I showed you.
-
5:21 - 5:25And we can take all that raw data
and treat it in very interesting ways. -
5:26 - 5:28So, Superman can fly.
-
5:28 - 5:30Some other heroes can become invisible.
-
5:31 - 5:35But what about a new power
for a future superhero: -
5:35 - 5:37To see around corners.
-
5:38 - 5:43The idea is that we could
shine some light on the door, -
5:43 - 5:45it's going to bounce, go inside the room,
-
5:45 - 5:48some of that is going to reflect
back on the door, -
5:48 - 5:49and then back to the camera.
-
5:49 - 5:52And we could exploit
these multiple bounces of light. -
5:53 - 5:55And it's not science fiction.
We have actually built it. -
5:55 - 5:57On the left, you see our femto-camera.
-
5:57 - 6:00There's a mannequin hidden behind a wall,
-
6:00 - 6:02and we're going to bounce
light off the door. -
6:03 - 6:06So after our paper was published
in Nature Communications, -
6:06 - 6:08it was highlighted by Nature.com,
-
6:08 - 6:11and they created this animation.
-
6:11 - 6:12(Music)
-
6:12 - 6:15[A laser pulse is fired]
-
6:15 - 6:18(Music)
-
6:18 - 6:21Ramesh Raskar: We're going to fire
those bullets of light, -
6:21 - 6:24and they're going to hit this wall,
-
6:24 - 6:27and because of the packet of the photons,
-
6:27 - 6:29they will scatter in all the directions,
-
6:29 - 6:31and some of them will reach
our hidden mannequin, -
6:31 - 6:35which in turn will again
scatter that light, -
6:35 - 6:39and again in turn, the door will reflect
some of that scattered light. -
6:41 - 6:44And a tiny fraction of the photons
will actually come back to the camera, -
6:44 - 6:45but most interestingly,
-
6:45 - 6:48they will all arrive
at a slightly different time slot. -
6:49 - 6:54(Music)
-
6:54 - 6:56And because we have a camera
that can run so fast -- -
6:56 - 6:59our femto-camera --
it has some unique abilities. -
6:59 - 7:02It has very good time resolution,
-
7:02 - 7:05and it can look at the world
at the speed of light. -
7:06 - 7:09And this way, we know the distances,
of course to the door, -
7:09 - 7:11but also to the hidden objects,
-
7:11 - 7:14but we don't know which point
corresponds to which distance. -
7:14 - 7:18(Music)
-
7:18 - 7:22By shining one laser,
we can record one raw photo, -
7:22 - 7:25which, if you look on the screen,
doesn't really make any sense. -
7:25 - 7:27But then we will take
a lot of such pictures, -
7:27 - 7:29dozens of such pictures,
put them together, -
7:29 - 7:32and try to analyze
the multiple bounces of light, -
7:32 - 7:35and from that, can we see
the hidden object? -
7:35 - 7:37Can we see it in full 3D?
-
7:38 - 7:40So this is our reconstruction.
-
7:40 - 7:45(Music)
-
7:45 - 7:52(Applause)
-
7:53 - 7:54Now, we have some ways to go
-
7:54 - 7:57before we take this
outside the lab on the road, -
7:57 - 8:01but in the future, we could create
cars that avoid collisions -
8:01 - 8:03with what's around the bend.
-
8:04 - 8:08Or we can look for survivors
in hazardous conditions -
8:08 - 8:11by looking at light reflected
through open windows. -
8:12 - 8:17Or we can build endoscopes that can see
deep inside the body around occluders, -
8:17 - 8:19and also for cardioscopes.
-
8:19 - 8:22But of course,
because of tissue and blood, -
8:22 - 8:23this is quite challenging,
-
8:23 - 8:25so this is really a call for scientists
-
8:25 - 8:27to start thinking about femto-photography
-
8:27 - 8:29as really a new imaging modality
-
8:29 - 8:33to solve the next generation
of health-imaging problems. -
8:33 - 8:37Now, like Doc Edgerton,
a scientist himself, -
8:37 - 8:39science became art --
-
8:39 - 8:42an art of ultra-fast photography.
-
8:43 - 8:44And I realized
-
8:44 - 8:47that all the gigabytes of data
that we're collecting every time, -
8:48 - 8:50are not just for scientific imaging.
-
8:50 - 8:56But we can also do a new form
of computational photography, -
8:56 - 8:58with time-lapse and color coding.
-
8:59 - 9:01And we look at those ripples.
-
9:01 - 9:02Remember:
-
9:02 - 9:07The time between each of those ripples
is only a few trillionths of a second. -
9:09 - 9:11But there's also something
funny going on here. -
9:11 - 9:14When you look at the ripples
under the cap, -
9:14 - 9:16the ripples are moving away from us.
-
9:17 - 9:19The ripples should be moving towards us.
-
9:19 - 9:20What's going on here?
-
9:20 - 9:27It turns out, because we're recording
nearly at the speed of light, -
9:27 - 9:29we have strange effects,
-
9:29 - 9:32and Einstein would have loved
to see this picture. -
9:32 - 9:33(Laughter)
-
9:33 - 9:36The order at which events
take place in the world -
9:36 - 9:40appears in the camera
sometimes in reversed order. -
9:41 - 9:44So by applying the corresponding
space and time warp, -
9:44 - 9:47we can correct for this distortion.
-
9:49 - 9:53So whether it's for photography
around corners, -
9:53 - 9:57or creating the next generation
of health imaging, -
9:57 - 10:00or creating new visualizations,
-
10:00 - 10:02since our invention,
-
10:02 - 10:07we have open-sourced all the data
and details on our website, -
10:07 - 10:14and our hope is that the DIY,
the creative and the research communities -
10:14 - 10:19will show us that we should stop obsessing
about the megapixels in cameras -- -
10:19 - 10:20(Laughter)
-
10:21 - 10:25and start focusing
on the next dimension in imaging. -
10:26 - 10:27It's about time.
-
10:27 - 10:28Thank you.
-
10:29 - 10:35(Applause)
- Title:
- Imaging at a trillion frames per second
- Speaker:
- Ramesh Raskar
- Description:
-
Ramesh Raskar presents femto-photography, a new type of imaging so fast it shows the world one trillion frames per second, so detailed it shows light itself in motion. This technology may someday be used to build cameras that can look “around” corners or see inside the body without X-rays.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 11:02
Camille Martínez edited English subtitles for Imaging at a trillion frames per second | ||
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Jenny Zurawell edited English subtitles for Imaging at a trillion frames per second | ||
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Thu-Huong Ha accepted English subtitles for Imaging at a trillion frames per second | ||
Thu-Huong Ha edited English subtitles for Imaging at a trillion frames per second |
Krystian Aparta
The English transcript was updated on 7/2/2015.