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  • - [William] You have seen this eye chart before.

    - [威廉]你以前見過這個眼圖。

  • It's at the DMV, it's at the optometrist,

    是在車管所,是在驗光師那裡。

  • it's in doctor's offices all over the place.

    它是在醫生的辦公室 所有的地方。

  • You probably know that font as the eye chart font.

    你可能知道那個字體是眼圖字體。

  • And, you definitely know that huge E.

    而且,你肯定知道那個巨大的E。

  • This thing is a dead simple tool for testing eyesight

    這東西是測試視力的簡單工具。

  • and it's helped millions of people see better.

    並幫助數百萬人看得更清楚。

  • - But, as simple as it is, there's some very precise math

    - 但是,雖然簡單,但也有一些非常精確的數學知識

  • hidden away in those block letters.

    藏在那些方塊字裡。

  • It doesn't just tell you if you need glasses,

    它不只是告訴你是否需要眼鏡。

  • it tells you something about the fundamental limits

    它告訴你一些關於基本限制

  • of human vision.

    的人類視覺。

  • - And, we wanted to put that math to the test

    - 而且,我們想把這個數學的測試。

  • on a slightly ridiculous scale.

    在一個略顯荒謬的規模。

  • We've got the Coast Guard coming by.

    海岸警衛隊來了。

  • Well, let's back up.

    好吧,我們退後。

  • The eye chart we all know and love was created back

    我們所熟知和喜愛的眼形圖,早在上世紀90年代就被創造出來了。

  • in 1862 by a Dutch ophthalmologist named Herman Snellen.

    1862年,由一位名叫赫爾曼-斯奈倫的荷蘭眼科醫生。

  • His early prototypes used abstract shapes,

    他的早期原型使用了抽象的形狀。

  • but he eventually settled on letters.

    但他最終還是選擇了信。

  • And the designed hasn't changed much since then.

    而且設計的也沒有什麼變化。

  • The chart is designed to measure one very particular aspect

    該圖表的設計是為了衡量一個非常特殊的方面

  • of our eyesight, visual acuity,

    我們的視力,視力。

  • or our ability to see very fine detail.

    或者說我們能夠看到非常精細的細節。

  • It's basically the resolution of the eye.

    基本上就是眼睛的分辨率。

  • Now here resolution isn't measured in pixels,

    現在這裡的分辨率不是以像素來衡量的。

  • it's measured in degrees, like of an angle.

    它是以度來衡量的,就像一個角度。

  • Which is weird, but here's why.

    這很奇怪,但這是為什麼。

  • - [Rachel] Say you're looking at two lights shining

    - 假設你看到的是兩盞燈在閃耀

  • at you from a distance, you can tell them apart

    隔行如隔山,如隔靴搔癢

  • because the light from each source is traveling

    因為每個源頭的光都在傳播

  • through your eye and hitting a different set

    通過你的眼睛和打不同的一組

  • of light sensitive sells, called photoreceptors.

    的光敏感賣點,稱為光感受器。

  • If you move the lights closer together,

    如果你把燈移近一點。

  • they'll start hitting photoreceptors

    他們會開始打擊光感受器。

  • that are closer to each other.

    彼此比較接近的。

  • Especially because, as the light travels through the eye,

    特別是因為,當光線穿過眼睛時。

  • it spreads out a little bit.

    它分散了一點。

  • Eventually, the two lights will blend together

    最終,這兩盞燈會融合在一起

  • and your brain will start to interpret them as one.

    你的大腦會開始把它們解釋為一個整體。

  • That angle, between the two paths of light right

    那個角度,在兩條光路之間的權利。

  • as you lose the ability to pick them apart,

    因為你失去了把它們挑開的能力。

  • that's the resolution limit of your eye.

    那是你眼睛的分辨率極限。

  • For healthy adults, it's on the scale

    對於健康的成年人來說,它的規模

  • of just 1/60 of a degree, also known as one arcminute.

    僅為1/60度,又稱1弧分。

  • - Snellen's eye chart is designed

    - 斯奈倫的眼圖設計

  • with this resolution limit in mind.

    考慮到這個分辨率的限制。

  • Take that little E in the middle.

    就拿中間的那個小E來說吧。

  • It's built on a five by five grid,

    它是建立在一個五乘五的網格上。

  • so that's the black lines and white spaces

    黑線白格

  • are all the same width, about a 16th of an inch.

    都是一樣的寬度,大約16英寸。

  • If you stand 20 feet away and look at that little E,

    如果你站在20英尺外,看著那個小E。

  • each little black bar or space,

    每個小黑條或空間。

  • is exactly one arcminute thick.

    正好是一角分厚。

  • If you can read most of the letters in that row

    如果你能讀懂這一行的大部分字母的話

  • at 20 feet away, you have 20/20 vision.

    在20英尺外,你有20/20的視野。

  • Meaning, at 20 feet, the patterns of white and black

    意思是說,在20英尺處,白色和黑色的花紋

  • are just at the limit of your eye's resolving power.

    只是在你眼睛的解析力的極限。

  • Now, you might be able to read a row or two beneath 20/20,

    現在,你也許能讀懂20/20下面的一兩行字。

  • most adults actually can.

    大多數成年人其實都可以。

  • In fact, 20/20 was never defined as perfect or even average,

    事實上,20/20從來沒有被定義為完美甚至是平均。

  • it's just a baseline to measure everything against.

    它只是一個基線來衡量一切。

  • The row beneath that is the 20/15 line.

    下面那一排是20/15線。

  • That means if you have 20/20 acuity,

    也就是說,如果你有20/20的敏銳度。

  • you'd have to walk forward five feet to see it clearly.

    你得往前走5英尺才能看清楚。

  • - All in all, with corrective lenses,

    - 總而言之,帶著矯正鏡。

  • there isn't actually a huge range

    其實範圍並不大

  • in acuity from one person to another.

    在敏銳度上從一個人到另一個人。

  • Partly, because we have similar densities

    部分原因是我們的密度相似

  • of photoreceptors in our eyes.

    我們眼睛裡的光感受器的。

  • It's like we're all taking photos

    好像我們都在拍照一樣。

  • with the same camera sensor.

    具有相同的相機傳感器。

  • Compare that with other animals like eagles,

    與老鷹等其他動物相比。

  • which have a very different optical setup than we do,

    它有一個非常不同的光學設置與我們做。

  • including many more photoreceptors.

    包括更多的光感受器。

  • Their eyes are camera sensors optimized

    他們的眼睛是經過優化的相機傳感器

  • for spotting rabbits from midair.

    用於從半空中發現兔子。

  • - Whatever your resolution limit is,

    - 不管你的分辨率極限是多少。

  • you can use it to calculate your own acuity

    你可以用它來計算你自己的敏銳度。

  • at different distances.

    在不同的距離。

  • Based on the Snellen chart, Rachel's acuity

    根據Snellen圖表,Rachel的敏銳度為:

  • is a bit better than 20/20, which makes

    比20/20好一點,這就使得。

  • her maximum resolution just under one arcminute.

    她的最大分辨率只有不到一弧分。

  • So, let's have a little fun with that.

    所以,讓我們來玩一玩吧。

  • All we're gonna do is plant you in front

    我們要做的就是把你安插在...

  • of this window right here, and we're gonna

    這個窗口的權利在這裡,而我們要去

  • go out there and show you some very large E's,

    去那裡給你看一些非常大的E的。

  • and all you have to do is tell us if you can identify the E.

    而你要做的就是告訴我們,如果你能識別E。

  • We'll start small, that pier

    我們從小事做起,那個碼頭

  • is about 1500 feet away from us.

    距離我們大約1500英尺。

  • Since Rachel's acuity is a little better

    因為Rachel的敏銳度更好一些

  • than one arcminute, she should comfortable see an E

    比一弧分,她應該舒適地看到一個E。

  • if it's about 25 inches across.

    如果它是大約25英寸寬。

  • Hello?

    喂?

  • - [Rachel] Hi.

    - [雷切爾]嗨。

  • - Hi, I'm going to show you an E,

    - 嗨,我要給你看一個E。

  • and you tell me if it's facing the right way,

    你告訴我它的方向是否正確。

  • if it's backwards.

    如果是倒退。

  • - Okay.

    - 好吧,我知道了

  • - [William] Okay, ready?

    - [威廉]好了,準備好了嗎?

  • Which way is the E facing?

    E朝哪邊?

  • - The open part of the E is facing towards the sky.

    - E的開放部分是朝向天空的。

  • - [William] Perfect.

    - [威廉]完美。

  • Now for the big finish.

    現在是大結局。

  • Treasure Island out there in the bay,

    金銀島在海灣裡。

  • is about two miles away, so to pull off the same eye exam,

    是大約兩英里的距離,所以要拉開同樣的眼睛檢查。

  • we're gonna need a much bigger E, like 15 feet tall.

    我們需要一個更大的E,像15英尺高。

  • Here we go, alright, gently, gently.

    我們走吧,好吧,輕輕地,輕輕地。

  • Oh wind's catching it.

    哦,風把它抓住了。

  • Did you see it?

    你看到了嗎?

  • - I see an E, and it's pointed to the right.

    - 我看到一個E,而且是指向右邊。

  • - [William] Tentative pointed to the right.

    - [威廉]坦坦蕩蕩地指著右邊。

  • That is correct.

    這是正確的。

  • - (laughs) The last thing to mention here

    - (笑)這裡最後要提到的是

  • is that acuity is important but it's not the be all end all,

    敏銳度是重要的,但它不是所有的一切。

  • your ability to sense movement, color, contrast,

    你對運動、色彩、對比的感知能力。

  • depth, all of that factors into successful eyesight.

    深度,所有這些因素都是成功的視力。

  • So acuity is just one tool of many

    所以敏銳度只是眾多工具中的一種

  • to help you make sense of the world.

    來幫助你理解這個世界。

  • - Now we've got the Coast Guard coming by.

    - 現在,我們已經得到了海岸警衛隊的到來。

  • We are happy to be here testing the Coast Guard

    我們很高興能在這裡測試海岸警衛隊。

  • on their visual acuity.

    對他們的視力。

  • Okay, I think we're done.

    好了,我想我們已經完成了。

  • Hey everyone, thank you so much for watching.

    大家好,非常感謝大家的觀看。

  • This is part of the brand new Verge Science YouTube channel.

    這是全新的Verge Science YouTube頻道的一部分。

  • We're putting a video out every week on this channel,

    我們每週都會在這個頻道上放一段視頻。

  • so if this is the type of thing you're looking for,

    所以如果你要找的是這種類型的東西。

  • hit the SUBSCRIBE button and come back every week.

    點擊訂閱按鈕,每週回來。

  • And, let us know in the comments

    而且,讓我們在評論中知道

  • what kind of thing you wanna see,

    你想看到什麼樣的東西。

  • because we're gonna be doing a lot more.

    因為我們會做得更多。

- [William] You have seen this eye chart before.

- [威廉]你以前見過這個眼圖。

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B1 中級 中文 美國腔 分辨率 感受器 視力 眼睛 警衛隊 威廉

Testing the limits of human vision

  • 633 40
    Samuel 發佈於 2018 年 06 月 20 日
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