Imaging at a trillion frames per second
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0:01 - 0:07Doc Edgerton inspired us with awe and curiosity
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0:07 - 0:12with this photo of a bullet piercing through an apple,
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0:12 - 0:17and exposure just a millionth of a second.
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0:17 - 0:24But now, 50 years later, we can go a million times faster
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0:24 - 0:28and see the world not at a million,
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0:28 - 0:30or a billion,
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0:30 - 0:33but one trillion frames per second.
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0:33 - 0:38I present you a new type of photography,
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0:38 - 0:40femto-photography,
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0:40 - 0:44a new imaging technique so fast
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0:44 - 0:49that it can create slow motion videos of light in motion.
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0:49 - 0:52And with that, we can create cameras
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0:52 - 0:54that can look around corners,
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0:54 - 0:56beyond line of sight
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0:56 - 1:01or see inside our body without an X-ray,
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1:01 - 1:06and really challenge what we mean by a camera.
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1:06 - 1:10Now if I take a laser pointer and turn it on and off
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1:10 - 1:12in one trillionth of a second --
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1:12 - 1:15which is several femtoseconds --
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1:15 - 1:18I'll create a packet of photons
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1:18 - 1:20barely a millimeter wide,
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1:20 - 1:23and that packet of photons, that bullet,
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1:23 - 1:25will travel at the speed of light,
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1:25 - 1:29and, again, a million times faster than an ordinary bullet.
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1:29 - 1:34Now, if you take that bullet and take this packet of photons
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1:34 - 1:37and fire into this bottle,
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1:37 - 1:42how will those photons shatter into this bottle?
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1:42 - 1:46How does light look in slow motion?
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2:06 - 2:10Now, the whole event -- (Applause)
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2:10 - 2:14(Applause)
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2:14 - 2:17Now, remember, the whole event
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2:17 - 2:20is effectively taking place in less than a nanosecond
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2:20 - 2:22— that's how much time it takes for light to travel —
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2:22 - 2:27but I'm slowing down in this video by a factor of 10 billion
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2:27 - 2:30so you can see the light in motion.
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2:30 - 2:35But, Coca-Cola did not sponsor this research. (Laughter)
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2:35 - 2:37Now, there's a lot going on in this movie,
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2:37 - 2:39so let me break this down and show you what's going on.
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2:39 - 2:43So, the pulse enters the bottle, our bullet,
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2:43 - 2:45with a packet of photons that start traveling through
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2:45 - 2:47and that start scattering inside.
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2:47 - 2:49Some of the light leaks, goes on the table,
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2:49 - 2:52and you start seeing these ripples of waves.
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2:52 - 2:55Many of the photons eventually reach the cap
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2:55 - 2:58and then they explode in various directions.
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2:58 - 3:00As you can see, there's a bubble of air,
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3:00 - 3:01and it's bouncing around inside.
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3:01 - 3:04Meanwhile, the ripples are traveling on the table,
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3:04 - 3:06and because of the reflections at the top,
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3:06 - 3:09you see at the back of the bottle, after several frames,
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3:09 - 3:12the reflections are focused.
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3:12 - 3:18Now, if you take an ordinary bullet
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3:18 - 3:22and let it go the same distance and slow down the video
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3:22 - 3:24again by a factor of 10 billion, do you know
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3:24 - 3:30how long you'll have to sit here to watch that movie?
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3:30 - 3:34A day, a week? Actually, a whole year.
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3:34 - 3:38It'll be a very boring movie — (Laughter) —
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3:38 - 3:42of a slow, ordinary bullet in motion.
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3:42 - 3:47And what about some still-life photography?
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3:53 - 3:58You can watch the ripples again washing over the table,
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3:58 - 4:01the tomato and the wall in the back.
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4:01 - 4:05It's like throwing a stone in a pond of water.
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4:07 - 4:11I thought, this is how nature paints a photo,
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4:11 - 4:14one femto frame at a time,
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4:14 - 4:19but of course our eye sees an integral composite.
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4:19 - 4:22But if you look at this tomato one more time,
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4:22 - 4:25you will notice, as the light washes over the tomato,
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4:25 - 4:28it continues to glow. It doesn't become dark.
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4:28 - 4:31Why is that? Because the tomato is actually ripe,
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4:31 - 4:33and the light is bouncing around inside the tomato,
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4:33 - 4:38and it comes out after several trillionths of a second.
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4:38 - 4:40So, in the future, when this femto-camera
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4:40 - 4:42is in your camera phone,
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4:42 - 4:44you might be able to go to a supermarket
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4:44 - 4:48and check if the fruit is ripe without actually touching it.
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4:48 - 4:54So how did my team at MIT create this camera?
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4:54 - 4:55Now, as photographers, you know,
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4:55 - 5:00if you take a short exposure photo, you get very little light,
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5:00 - 5:02but we're going to go a billion times faster
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5:02 - 5:04than your shortest exposure,
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5:04 - 5:05so you're going to get hardly any light.
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5:05 - 5:07So, what we do is we send that bullet,
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5:07 - 5:10those packet of photons, millions of times,
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5:10 - 5:13and record again and again with very clever synchronization,
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5:13 - 5:15and from the gigabytes of data,
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5:15 - 5:17we computationally weave together
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5:17 - 5:21to create those femto-videos I showed you.
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5:21 - 5:23And we can take all that raw data
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5:23 - 5:26and treat it in very interesting ways.
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5:26 - 5:28So, Superman can fly.
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5:28 - 5:30Some other heroes can become invisible,
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5:30 - 5:35but what about a new power for a future superhero:
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5:35 - 5:38to see around corners?
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5:38 - 5:43The idea is that we could shine some light on the door.
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5:43 - 5:45It's going to bounce, go inside the room,
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5:45 - 5:48some of that is going to reflect back on the door,
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5:48 - 5:49and then back to the camera,
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5:49 - 5:53and we could exploit these multiple bounces of light.
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5:53 - 5:55And it's not science fiction. We have actually built it.
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5:55 - 5:57On the left, you see our femto-camera.
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5:57 - 6:00There's a mannequin hidden behind a wall,
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6:00 - 6:03and we're going to bounce light off the door.
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6:03 - 6:05So after our paper was published
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6:05 - 6:07in Nature Communications,
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6:07 - 6:09it was highlighted by Nature.com,
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6:09 - 6:11and they created this animation.
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6:11 - 6:18(Music)
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6:18 - 6:21We're going to fire those bullets of light,
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6:21 - 6:24and they're going to hit this wall,
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6:24 - 6:27and because the packet of the photons,
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6:27 - 6:29they will scatter in all the directions,
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6:29 - 6:32and some of them will reach our hidden mannequin,
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6:32 - 6:34which in turn will again scatter that light,
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6:34 - 6:38and again in turn the door will reflect
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6:38 - 6:40some of that scattered light,
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6:40 - 6:43and a tiny fraction of the photons will actually
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6:43 - 6:45come back to the camera, but most interestingly,
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6:45 - 6:49they will all arrive at a slightly different time slot.
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6:49 - 6:54(Music)
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6:54 - 6:56And because we have a camera that can run so fast,
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6:56 - 6:59our femto-camera, it has some unique abilities.
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6:59 - 7:02It has very good time resolution,
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7:02 - 7:06and it can look at the world at the speed of light.
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7:06 - 7:09And this way, we know the distances, of course to the door,
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7:09 - 7:11but also to the hidden objects,
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7:11 - 7:13but we don't know which point corresponds
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7:13 - 7:15to which distance.
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7:15 - 7:18(Music)
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7:18 - 7:22By shining one laser, we can record one raw photo, which,
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7:22 - 7:25you look on the screen, doesn't really make any sense,
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7:25 - 7:27but then we will take a lot of such pictures,
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7:27 - 7:29dozens of such pictures, put them together,
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7:29 - 7:32and try to analyze the multiple bounces of light,
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7:32 - 7:35and from that, can we see the hidden object?
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7:35 - 7:38Can we see it in full 3D?
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7:38 - 7:41So this is our reconstruction. (Music)
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7:41 - 7:44(Music)
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7:44 - 7:53(Music) (Applause)
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7:53 - 7:55Now we have some ways to go before we take this
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7:55 - 7:58outside the lab on the road, but in the future,
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7:58 - 8:01we could create cars that avoid collisions
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8:01 - 8:03with what's around the bend,
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8:03 - 8:07or we can look for survivors in hazardous conditions
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8:07 - 8:12by looking at light reflected through open windows,
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8:12 - 8:14or we can build endoscopes that can see
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8:14 - 8:17deep inside the body around occluders,
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8:17 - 8:19and also for cardioscopes.
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8:19 - 8:22But of course, because of tissue and blood,
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8:22 - 8:24this is quite challenging, so this is really a call
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8:24 - 8:27for scientists to start thinking about femto-photography
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8:27 - 8:30as really a new imaging modality to solve
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8:30 - 8:33the next generation of health imaging problems.
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8:33 - 8:37Now, like Doc Edgerton, a scientist himself,
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8:37 - 8:42science became art, an art of ultra-fast photography,
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8:42 - 8:46and I realized that all the gigabytes of data
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8:46 - 8:48that we're collecting every time
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8:48 - 8:51is not just for scientific imaging, but we can also do
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8:51 - 8:55a new form of computational photography
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8:55 - 8:59with time-lapse and color-coding,
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8:59 - 9:02and we look at those ripples. Remember,
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9:02 - 9:04the time between each of those ripples is only
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9:04 - 9:09a few trillionths of a second.
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9:09 - 9:11But there's also something funny going on here.
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9:11 - 9:13When you look at the ripples under the cap,
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9:13 - 9:17the ripples are moving away from us.
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9:17 - 9:19The ripples should be moving towards us.
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9:19 - 9:21What's going on here?
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9:21 - 9:23It turns out, because we're recording
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9:23 - 9:27nearly at the speed of light,
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9:27 - 9:29we have strange effects,
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9:29 - 9:33and Einstein would have loved to see this picture.
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9:33 - 9:36The order at which events take place in the world
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9:36 - 9:41appear in the camera with sometimes reversed order,
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9:41 - 9:44so by applying the corresponding space and time warp,
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9:44 - 9:48we can correct for this distortion.
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9:48 - 9:53So whether it's for photography around corners,
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9:53 - 9:57or creating the next generation of health imaging,
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9:57 - 10:00or creating new visualizations,
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10:00 - 10:03since our invention, we have open-sourced
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10:03 - 10:07all the data and details on our website, and our hope
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10:07 - 10:14is that the DIY, the creative and the research community
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10:14 - 10:17will show us that we should stop obsessing about
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10:17 - 10:21the megapixels in cameras — (Laughter) —
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10:21 - 10:26and start focusing on the next dimension in imaging.
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10:26 - 10:30It's about time. Thank you. (Applause)
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10:30 - 10:40(Applause)
- Title:
- Imaging at a trillion frames per second
- Speaker:
- Ramesh Raskar
- Description:
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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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Krystian Aparta 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.