Most people will pick out a phantom-like picture of Albert Einstein. But if you see a Hollywood pin-up, you may need a trip to the opticians。
大多数人看到的是阿尔伯特·爱因斯坦的一张诡异照片。如果你看到的是好莱坞女明星，也许你就得去一趟眼镜店了。
At normal viewing distance, healthy eyes should be able to pick up the fine lines on Einstein's face, causing the brain to disregard Marilyn Monroe's image altogether。
在正常的观察距离下，健康的眼睛能够捕捉到爱因斯坦脸上的线条，这让大脑可以完全忽略玛丽莲·梦露的图像。
This classic optical illusion was created several years ago by neuroscientists at the Massachusetts Institute of Technology。
这一视错觉经典图像是麻省理工学院神经系统科学家们几年前制作的。

In a recent video, Asap Science highlighted the process behind the trick, which can also be seen in a still image by anyone if they move closer and then farther away from the screen。
在最近的视频中，YouTube科普大神Asap Science揭露了这个视错觉背后的操作过程，只要观察者调整自己与屏幕的距离，那么每个人都能从一幅静态图片中观察到图片的变化。
‘Depending on how well you're able to focus or pick up contrast, your eye will only pick out details,’ the video explains.

视频中这样解释道：“这都取决于你的聚焦能力和识别对比度的能力，你的眼睛只会关注细节。”
‘Up close, we're generally able to pick up fine details like Einstein's moustache and wrinkles。
“近距离观察时，我们大都能够观察到图片上的细节，比如爱因斯坦脸上的小胡子和皱纹。
‘But as the distance increases, or if your vision is poor and creates a more blurred image in the first place, your ability to pick up details fades away。
“但当观察距离被拉长，或是视力问题让你看到的图像变得模糊时，你观察事物细节的能力就会逐渐消失。
‘Instead you only see general features, like the shape of mouth, nose and hair, and are left seeing Marilyn Monroe. ‘
“这时，我们只能看到大致的容貌特征，比如嘴型、鼻子和发型，因此，我们最终会看到是玛丽莲·梦露的画像。”
The MIT team, led by Dr Aude Oliva, has spent over a decade creating hybrid optical illusions that show how images can be hidden with textures, words and other objects。
由奥德·奥利瓦博士领衔的麻省理工团队经过十年的努力，最终制作出了这些混合视错觉图像，向我们展示了图像是怎样被纹理、文字和其他图案隐藏起来的。
'Marilyn Einstein' was created by superimposing a blurry picture of Marilyn Monroe over a picture of Albert Einstein drawn in fine lines。
这张“玛丽莲·爱因斯坦”混合图像由梦露的模糊照片叠加在爱因斯坦的细线素描上组成。
Features with a high spatial frequency are only visible when viewing them close up, and those with low spatial frequencies are only visible at a distance。
高空间频率的容貌特征只有在近距离的情况下才能看出，而那些低空间频率的图像特征只能在远距离的情况下可见。
Combining pictures of the two produces a single image which changes when the viewer moves closer or farther away from the screen。
当我们把这两种图像叠加在一起时，观察者可以通过调整自己与屏幕的距离，而看到不同的图像。
Dr Oliva's group say these images not only reveal vision problems, but can also highlight how the brain processes information。
奥利瓦博士的团队称，这类图片不仅能暴露视力问题，还显示了我们的大脑是如何处理信息的。
In one study, participants were shown hybrid images for just of 30 milliseconds, and only recognised the low spatial resolution, or blurry, component of the image。
在一项研究中，当参与者只有30毫秒观察混合图像时，他们只能看到低空间分辨率的，或是模糊的局部图像内容。