Animation basics: The optical illusion of motion - TED-Ed · TED-Ed
揭秘动画如何通过连续画面制造运动感，了解视觉暂留现象及其在电影和动画中的应用，适合练习科技与文化类词汇。
Take a series of still, sequential images.
拍摄一系列连续的、静止的图像。
Let's look at them one by one.
我们逐一来看它们吧。
Faster.
更快。
Now, let's remove the gaps, go faster still.
现在，让我们消除那些“间隙”（即不必要的停顿或间隔），让动作变得更加流畅、更快。
Wait for it ...
等着瞧吧……
Bam!
砰！
Motion!
请开始动议吧！
Why is that?
为什么会这样呢？
Intellectually, we know we're just looking at a series of still images, but when we see them change fast enough,
从理智上讲，我们知道自己看到的只是一系列静止的图像；然而当这些图像变化得足够快时……
they produce the optical illusion of appearing as a single, persistent image that's gradually changing form and position.
它们会产生一种视觉错觉：看起来像是一个单一的、持续存在的图像，而这个图像的形状和位置正在逐渐发生变化。
This effect is the basis for all motion picture technology, from our LED screens of today to their 20th-century cathode ray forebearers,
这种效应是所有电影技术的基础——无论是我们如今使用的 LED 屏幕，还是 20 世纪早期的阴极射线显示器。
from cinematic film projection to the novelty toy,
从电影放映技术到新型玩具，
even, it's been suggested, all the way back to the Stone Age when humans began painting on cave walls.
甚至有人认为，这种现象可以追溯到石器时代——那时人类就开始在洞穴墙壁上绘画了。
This phenomenon of perceiving apparent motion in successive images is due to a characteristic of human perception historically referred to as "persistence of vision."
这种现象——即在连续的图像中感知到明显的运动——其实是由于人类视觉系统的一种特性所导致的。这种特性在历史上被称为“视觉暂留效应”（即人们能够在图像消失后的一段时间内继续感知到该图像的存在）。
The term is attributed to the English-Swiss physicist Peter Mark Roget,
这一术语归功于英瑞物理学家彼得·马克·罗杰（Peter Mark Roget）。
who, in the early 19th century, used it to describe a particular defect of the eye
在19世纪初，人们用这个词来描述眼睛的一种特定缺陷。
that resulted in a moving object appearing to be still when it reached a certain speed.
这种现象导致一个运动中的物体在达到一定速度时看起来仿佛静止不动了。
Not long after, the term was applied to describe the opposite, the apparent motion of still images, by Belgian physicist Joseph Plateau,
不久之后，比利时物理学家约瑟夫·普拉托（Joseph Plateau）将这一术语用于描述相反的现象，即静止图像所呈现的“运动”效果。
inventor of the phenakistoscope.
菲纳基斯托斯科普（Phenakistoscope）的发明者。
He defined persistence of vision as the result of successive afterimages, which were retained and then combined in the retina,
他将“视觉暂留”现象定义为：由于一系列连续的残像在视网膜上被保留下来并最终结合在一起而产生的现象。
making us believe that what we were seeing is a single object in motion.
这让我们误以为所看到的是一个正在运动的整体（即一个单一的物体）。
This explanation was widely accepted in the decades to follow and up through the turn of the 20th century,
这一解释在随后几十年里被广泛接受，并一直延续到20世纪初。
when some began to question what was physiologically going on.
当一些人开始质疑身体内部究竟发生了哪些生理变化时……
In 1912, German psychologist Max Wertheimer outlined the basic primary stages of apparent motion using simple optical illusions.
1912年，德国心理学家马克斯·韦特海默通过简单的视错觉现象，阐述了“表观运动”（即人们所感知到的物体运动）的基本形成过程。
These experiments led him to conclude the phenomenon was due to processes which lie behind the retina.
这些实验使他得出结论：这种现象是由视网膜背后发生的某些生理过程所导致的。
In 1915, Hugo Münsterberg, a German-American pioneer in applied psychology,
1915年，雨果·闵斯特伯格（Hugo Münsterberg）——这位德裔美国应用心理学的先驱——
also suggested that the apparent motion of successive images is not due to their being retained in the eye,
还指出：连续图像所呈现的“运动效果”并非由于这些图像被眼睛“保留”下来（即图像在视觉系统中持续存在）。
but is superadded by the action of the mind.
但是这种特性是后天通过思维活动才被赋予的（即是由人类的意识或行为所决定的）。
In the century to follow, experiments by physiologists have pretty much confirmed their conclusions.
在接下来的一个世纪里，生理学家们的实验基本上证实了他们的结论。
As it relates to the illusion of motion pictures, persistence of vision has less to do with vision itself than how it's interpreted in the brain.
就电影中的运动错觉而言，“视觉暂留效应”（即观众在电影结束后仍能感觉到物体在继续移动的现象）与其说与视觉本身有关，不如说与大脑对视觉信息的解读方式有关。
Research has shown that different aspects of what the eye sees,
研究表明，眼睛所看到的内容包含多个不同的方面。
like form, color, depth, and motion, are transmitted to different areas of the visual cortex via different pathways from the retina.
诸如形状、颜色、明暗程度以及运动感等信息，都是通过视网膜上的不同神经通路传递到视觉皮层的不同区域的。
It's the continuous interaction of various computations in the visual cortex that stitch those different aspects together and culminate in the perception.
正是视觉皮层中各种计算过程之间的持续互动，将这些不同的信息片段串联起来，最终形成了我们的感知体验。
Our brains are constantly working, synchronizing what we see, hear, smell, and touch into meaningful experience in the moment-to-moment flow of the present.
我们的大脑一直在不停地运转，将我们所看到、听到、闻到和感受到的一切信息整合成有意义的体验，从而帮助我们在当下的生活中顺利地应对各种情况。
So, in order to create the illusion of motion in successive images,
因此，为了在连续的图像中创造出运动的错觉，
we need to get the timing of our intervals close to the speed at which our brains process the present.
我们需要将各个时间间隔的间隔长度调整得尽可能接近我们大脑处理当前信息时的速度。
So, how fast is the present happening according to our brains?
那么，根据我们大脑的认知方式，现在这个时刻（即“当下”）究竟发生得有多快呢？
Well, we can get an idea by measuring how fast the images need to be changing for the illusion to work.
嗯，我们可以通过测量图像需要以多快的速度变化才能产生这种视觉错觉来了解其中的原理。
Let's see if we can figure it out by repeating our experiment.
让我们通过重复实验来看看是否能够弄清楚这个问题。
Here's the sequence presented at a rate of one frame per two seconds with one second of black in between.
以下是视频的播放顺序：每两秒显示一帧画面，帧与帧之间会插入一秒钟的黑色背景。