Doc Edgerton inspired us with awe and curiosity with this photo of a bullet piercing through an apple, and exposure just a millionth of a second. But now, 50 years later, we can go a million times faster and see the world not at a million or a billion, but one trillion frames per second.
爱哲顿博士用这张子弹击穿苹果的照片 激起了我们的敬佩和好奇, 这张照片的曝光时间只有一百万分之一秒。 但现在,五十年后,我们可以再快一百万倍, 也就是不仅在一百万分之一秒, 或者十亿分之一秒, 而是在万亿分之一秒见捕捉到世界。
I present to you a new type of photography, femto-photography, a new imaging technique so fast that it can create slow motion videos of light in motion. And with that, we can create cameras that can look around corners, beyond line of sight, or see inside our body without an x-ray, and really challenge what we mean by a camera.
现在我给你展示一种新型照相技术, 叫做飞秒成像, 这是一种技术太快以至于 它能捕捉到光的运动。 所以用这个技术,我们可以制造 能看到光路拐角的照相机, 能看到视野之外 或者不用X光就能透视我们身体的照相机, 这种相机挑战了我们关于照相机的定义。
Now if I take a laser pointer and turn it on and off in one trillionth of a second -- which is several femtoseconds -- I'll create a packet of photons barely a millimeter wide. And that packet of photons, that bullet, will travel at the speed of light, and again, a million times faster than an ordinary bullet. Now, if you take that bullet and take this packet of photons and fire into this bottle, how will those photons shatter into this bottle? How does light look in slow motion?
现在,如果我用一个激光笔, 并且在万亿分之一秒内开关一次—— 也就是几飞秒—— 我就会制造一些光子, 这些光子仅仅是几毫米宽, 并且这些光子,像子弹一样, 会以光速前进, 也就是比子弹速度高一百万倍。 现在,如果你把这个子弹,这些光子 打入这个瓶子里, 这些光子会怎么样撞击瓶子? 光在慢动作下会是什么样?
[Light in Slow Motion ... 10 Billion x Slow]
Now, the whole event --
现在,着整个事情—— (鼓掌)
(Applause)
(鼓掌)
Now remember, the whole event is effectively taking place in less than a nanosecond -- that's how much time it takes for light to travel. But I'm slowing down in this video by a factor of 10 billion, so you can see the light in motion.
现在,请记住,这整个事情 其实是在一纳秒内发生的 ——也就是光走的时间—— 但现在我再把这个录像放慢一百万倍 让你看到运动中的光。
(Laughter)
但可口可乐可没有资助这个实验。 (笑声)
But Coca-Cola did not sponsor this research.
(Laughter)
Now, there's a lot going on in this movie, so let me break this down and show you what's going on. So the pulse enters the bottle, our bullet, with a packet of photons that start traveling through and that start scattering inside. Some of the light leaks, goes on the table, and you start seeing these ripples of waves. Many of the photons eventually reach the cap and then they explode in various directions. As you can see, there's a bubble of air and it's bouncing around inside. Meanwhile, the ripples are traveling on the table, and because of the reflections at the top, you see at the back of the bottle, after several frames, the reflections are focused.
现在,在这里有很多事会发生, 所以让我一件一件的展示。 现在,光束进入瓶子,也就是我们的子弹, 穿过瓶子, 并且在内部散射开来。 一些光流了出来,到了桌子上, 所以你开始看到这些波纹。 许多光子最终到达了瓶盖处 并且向四周散去。 你能看到,这里是一个空气泡, 它在里面反弹。 同时,波纹也到了桌子上, 并且因为在顶部的反射, 你能看到在瓶子底部,几帧之后, 反射汇聚了。
Now, if you take an ordinary bullet and let it go the same distance and slow down the video -- again, by a factor of 10 billion -- do you know how long you'll have to sit here to watch that movie?
现在,如果你用普通的子弹 走同样的路程,平且放慢视频, 同样是一百万倍,你知道 你需要等多久来看到这个全过程吗?
(Laughter)
A day, a week? Actually, a whole year. It'll be a very boring movie --
一天,一周?实际上,是一年。 这当然会很无聊 (笑声)
(Laughter)
of a slow, ordinary bullet in motion.
一个慢的,普通的子弹运动录像。
And what about some still-life photography? You can watch the ripples, again, washing over the table, the tomato and the wall in the back. It's like throwing a stone in a pond of water.
但一些静物照相又如何呢? 你可以又一次看到波纹在桌子上展开, 背景是西红柿和墙。 这就像在水池里扔一块石头。
I thought: this is how nature paints a photo, one femto frame at a time, but of course our eye sees an integral composite. But if you look at this tomato one more time, you will notice, as the light washes over the tomato, it continues to glow. It doesn't become dark. Why is that? Because the tomato is actually ripe, and the light is bouncing around inside the tomato, and it comes out after several trillionths of a second. So in the future, when this femto-camera is in your camera phone, you might be able to go to a supermarket and check if the fruit is ripe without actually touching it.
我想,这就是自然如何绘制的西红柿, 一飞秒一飞秒, 但当然我们眼睛看到的是整体的结合。 但如果你在看一下这个西红柿, 你就会注意到,当光在西红柿上走过时, 它一直在闪耀。它并没有变暗。 为什么?因为西红柿熟了, 并且光在西红柿内部反射, 在几万亿分之一秒后出来。 所以,在未来,当飞米成像相机 在你的手机里的时候, 你就可以去超市,
(Laughter)
不用摸就能检查一下水果是否熟了。
So how did my team at MIT create this camera? Now, as photographers, you know, if you take a short exposure photo, you get very little light. But we're going to go a billion times faster than your shortest exposure, so you're going to get hardly any light. So what we do is we send that bullet -- that packet of photons -- millions of times, and record again and again with very clever synchronization, and from the gigabytes of data, we computationally weave together to create those femto-videos I showed you.
那么,我在麻省理工学院的团队是怎么做出这个相机的呢? 现在,作为摄影师,你知道, 如果你想要短时曝光,你只有一点点光, 但我们需要比最短的曝光时间 快一百万倍, 所以你几乎得不到任何光。 所以,我们做的是, 把这些光子送进去,并重复百万多次, 每次都以极好的同步录像, 然后从几个GB的数据中, 我们“编织”起来一幅图, 而这幅图就是你们之前看到的。
And we can take all that raw data and treat it in very interesting ways. So, Superman can fly. Some other heroes can become invisible. But what about a new power for a future superhero: To see around corners. The idea is that we could shine some light on the door, it's going to bounce, go inside the room, some of that is going to reflect back on the door, and then back to the camera. And we could exploit these multiple bounces of light.
并且我们把所有的原始数据到算进去时, 进行很有趣的处理。 现在,超人能飞。 一些其他英雄能隐身, 但想象一个未来的超人: 他能看到拐角后面的东西。 这原理是我们可以把一些光打到门上, 这些光会反射进入房间, 一些会返回到门上, 然后进入照相机, 这样我们就可以利用这些光的反射。
And it's not science fiction. We have actually built it. On the left, you see our femto-camera. There's a mannequin hidden behind a wall, and we're going to bounce light off the door.
这可不是科幻片。我们真正的做出来了。 在左边,你看到了我们的飞秒成像相机。 在墙后面有一个人体模型, 我们将进行光反射。
So after our paper was published in Nature Communications, it was highlighted by Nature.com, and they created this animation.
所以,在我们的论文发表 在《自然》上后, 它被推荐到自然的官网上,
(Music)
然后他们创造了这个动画。
[A laser pulse is fired]
(音乐)
(Music)
我们将要发射这些光子弹,
Ramesh Raskar: We're going to fire those bullets of light, and they're going to hit this wall, and because of the packet of the photons, they will scatter in all the directions, and some of them will reach our hidden mannequin, which in turn will again scatter that light, and again in turn, the door will reflect some of that scattered light. And a tiny fraction of the photons will actually come back to the camera, but most interestingly, they will all arrive at a slightly different time slot.
它们将要撞击这个墙, 并且因为这束光 会散射到各个方向, 一些会最终打到我们的隐藏的假人上, 并且会继续散射, 知道这个门也会反射 一些光, 而一部分光会最终 返回到相机里,但最有趣的是, 他们会在略微不同的时间到达。
(Music)
(音乐)
And because we have a camera that can run so fast -- our femto-camera -- it has some unique abilities. It has very good time resolution, and it can look at the world at the speed of light. And this way, we know the distances, of course to the door, but also to the hidden objects, but we don't know which point corresponds to which distance.
而且因为我们有一个可以运行如此之快的相机, 也就是我们的飞秒相机,这个相机就有一些特别的能力。 它有很好的时间分辨率, 并且可以以光速捕捉世界。 所以这样,我们不仅知道相机到门的距离, 同时知道到隐藏物品的距离, 但我们不知道哪个点
(Music)
对应哪个距离。
By shining one laser, we can record one raw photo, which, if you look on the screen, doesn't really make any sense. But then we will take a lot of such pictures, dozens of such pictures, put them together, and try to analyze the multiple bounces of light, and from that, can we see the hidden object? Can we see it in full 3D?
(音乐) 通过用激光,我们能记录一个原始的照片, 也就是你们在屏幕上看到的这个,好像没什么意义, 但然后我们会拍很多照片, 很多很多,放到一起, 然后分析光的反射, 现在我们能看到那个隐藏的物体了吗? 我们能立体的看懂吗?
So this is our reconstruction.
这就是我们的模型重建。 (音乐)
(Music)
(音乐)
(Applause)
(音乐) (掌声)
Now, we have some ways to go before we take this outside the lab on the road, but in the future, we could create cars that avoid collisions with what's around the bend. Or we can look for survivors in hazardous conditions by looking at light reflected through open windows. Or we can build endoscopes that can see deep inside the body around occluders, and also for cardioscopes. But of course, because of tissue and blood, this is quite challenging, so this is really a call for scientists to start thinking about femto-photography as really a new imaging modality to solve the next generation of health-imaging problems.
现在我们在把他们应用到生活中 还有一些路要走, 但在未来,我们可以把这个技术放到车里, 这样车就能防止碰撞,因为他们能看到拐角, 或者我们可以搜寻幸存者, 因为我们能看到在窗户上反射的光, 或者我们可以建造透视仪, 来看到身体里的情况, 我们甚至可以透视心脏。 但当然,由于各种组织和血液的干扰, 这回相当困难, 所以我们呼吁科学家来真正重视飞秒成像, 把这个技术作为一种 解决下一代健康问题的新模型。
Now, like Doc Edgerton, a scientist himself, science became art -- an art of ultra-fast photography. And I realized that all the gigabytes of data that we're collecting every time, are not just for scientific imaging. But we can also do a new form of computational photography, with time-lapse and color coding. And we look at those ripples. Remember: The time between each of those ripples is only a few trillionths of a second.
现在,就像爱哲顿博士,一个科学家, 科学变成了艺术,一种高速摄影艺术, 而且我意识到我们每次 收集到的大量资料 不仅是科学成像, 而且还是一种新的计算性摄影, 这种技术蕴含了时间延迟和彩色编码, 我们看这些波纹。 记住,这些波纹之间的时间 仅仅是几个万亿分之一秒。
But there's also something funny going on here. When you look at the ripples under the cap, the ripples are moving away from us. The ripples should be moving towards us. What's going on here?
但有些有趣的事正在发生, 当你看到这些盖子下的波纹时, 他们正在离我们远去。 但这些波纹应该向我们移动。 发生了什么?
It turns out, because we're recording nearly at the speed of light, we have strange effects, and Einstein would have loved to see this picture.
结果是,因为我们在以接近光速 来录这些东西, 我们有一些奇怪的现象,
(Laughter)
爱因斯坦会相当高兴看到这些图片。
The order at which events take place in the world appears in the camera sometimes in reversed order. So by applying the corresponding space and time warp, we can correct for this distortion.
事件发生的顺序 在相机里有时候被反转了, 所以通过对应时间和空间的扭曲, 我们可以修正这个扭曲。
So whether it's for photography around corners, or creating the next generation of health imaging, or creating new visualizations, since our invention, we have open-sourced all the data and details on our website, and our hope is that the DIY, the creative and the research communities will show us that we should stop obsessing about the megapixels in cameras --
所以不管是看到拐角, 还是为下一代制造健康影像, 还是增加新的可视化, 自从我们的发明, 我们就已经把所有的资料和细节放到了我们的网上, 并且我们希望,这个DIY,这个创意的研究团体, 可以告诉我们
(Laughter)
我们不应该再迷上高像素——(笑声)——
and start focusing on the next dimension in imaging. It's about time.
而开始关注成像技术的另一个维度。 时间差不多了。谢谢。 (掌声)
Thank you.
(Applause)
(掌声)