A view of a microwave scan of the Duke logo taken through a wallbefore and after distortions have been removed. By taking into account thetypes of distortions typically created by flat, uniform walls, the newalgorithm allows for better scans without needing to know what the wall is madeof beforehand.
新算法已經摒棄微波透過牆壁前後扭曲變形對比來掃描Duke標識的方法。新的算法納入平坦、均勻的牆壁產生的各類扭曲變形類型，讓掃描更方便，無需事先知道牆壁的構成。
Researchers at Duke University have devised a way to see throughwalls using a narrow band of microwave frequencies without any advanceknowledge of what the walls are made out of. Besides having obviousapplications in the realm of security, the approach could lead to inexpensivedevices to help construction workers easily locate conduits, pipes and wires.
杜克大學的研究人員已經設計出一種方法，通過使用窄頻帶的微波頻率來觀察牆壁，而不需要事先知道牆壁是由什麼構成的。除了在安全領域有明顯的應用之外，這種方法還可以製造便宜的設備，幫助建築工人輕鬆定位水管，氣管和電線。
The study was published in the journal Optica on Dec. 5,2017.
"Most technologies that can see through walls use a broad rangeof frequencies, which makes them expensive," said Daniel Marks, associateresearch professor of electrical and computer engineering at Duke. "Theyalso don't have very good resolution. So while they might be fine for seeing aperson moving on the other side of a wall, they're terrible for finding thinconduits or wires."
該研究於2017年12月5日在Optica雜誌上發表。
杜克大學電氣與計算機工程副教授丹尼爾·馬克斯（Daniel Marks）表示：「大多數可以透視牆壁的技術需要的頻率範圍很廣，這使得它們很昂貴。 「他們也沒有很好的解決辦法，所以雖然看到一個人在牆的另一邊移動可能沒問題，但是找到細導管或者電線還是很難的。」
Current approaches also typically rely on knowing what material thewall is made out of before trying to see through it. This allows the softwareto predict how the wall will affect the scanning waves so that it can separatethe echoes and distortions from the solid objects being sought.
目前的方法通常還依賴於在試圖穿透牆壁之前知道牆壁是由什麼材料製成的。這使得軟體可以預測牆壁將如何影響掃描波，以便它可以從所尋求的固體物體中分離回波和扭曲。
In the new paper, Marks and his colleagues David R. Smith, the JamesB. Duke Professor of Electrical and Computer Engineering, and Okan Yurduseven,a postdoctoral researcher in electrical and computer engineering at Duke, takeadvantage of a wall's symmetry instead.
在這篇新論文中，Marks和他的同事杜克大學James B電氣和計算機工程教授David R. Smith和電子和計算機工程博士後Okan Yurduseven利用了牆的對稱性。
Because walls are generally flat and uniform in all directions, theydistort waves in a symmetrical fashion. The newly described technology usesthis symmetry to its advantage.
由於牆體大致平坦且各方向均勻，所以它們以對稱的方式扭曲波。描述中的新技術利用了這種對稱性。
"We wrote an algorithm that separates the data into parts—onethat shows circular symmetry and another that doesn't," explained Yurduseven."The data that doesn't have any symmetry is what we're trying tosee."
Yurduseven解釋說：「我們編寫了一種將數據分成若干部分的算法，一種顯示圓對稱，另一種不顯示。 「沒有任何對稱性的數據就是我們想要看到的。」
The technique uses only a single frequency to scan because it cutsdown on the number of interference patterns created by the wall andsingle-frequency emitters are much less expensive than broadband emitters.Sticking to a narrow range also means that a future device would be easier toclear with the Federal Communications Commission (FCC), as it would be easy toavoid interfering with microwave frequencies dedicated to othertechnologies, such as Wifi, cellular phone service and Bluetooth.
該技術僅使用單一頻率進行掃描，因為它減少了由牆壁產生的幹擾圖案的數量，而且單頻發射器比寬帶發射器便宜得多。利用狹窄的頻率範圍還意味著未來的設備將更容易通過聯邦通信委員會（FCC）批轉，因為這將容易避免幹擾專用於其他技術的微波頻率，諸如Wifi，蜂窩電話服務和藍牙。
The researchers built a prototype device to see how well it wouldwork. In their laboratory, they constructed a couple of different kindsof walls and then placedobjects behind them that a worker might want to find, like studs, electricalconduits, wires and junction boxes.
研究人員構建了一個原型設備，以了解它將如何工作。在他們的實驗室裡，他們建造了幾個不同類型的牆壁，並在牆壁後面放上工人可能想要發現的物體，例如立柱，電線管，電線和接線盒。
Looking at the raw data after scanning through gypsum plasterboard,it's difficult to make out anything other than a metal junction box, which is 4inches wide and 2 inches thick. But after analyzing the data and removing thesymmetrical patterns, the pictures clear considerably, and each individualcomponent is easily recognized.
通過掃描石膏板得到的原始數據，除了能發現4英寸寬，2英寸厚金屬接線盒外，很男透視任何其他東西。但是，在分析數據並消除對稱圖案之後，圖片清晰了，並且每個單獨的組件都容易識別。
"We envision combining this technique with a machine visionsystem that someone could move over a wall to see what's inside," saidMarks. "We think the technology has the price point and sensitivity tomake an impact on the market."
Marks表示：「我們設想將這種技術與機器視覺系統結合起來，讓人們可以在牆上移動，看看牆裡面是什麼。 「我們認為這種技術具有價格優勢及敏感性，會對市場產生影響。」
科技詞彙
Material 材料
Microwave 微波
Distortion 扭曲、變形
Flat 平的
Uniform 一致的
Algorithm 算法
Beforehand 事先
Narrow 窄的
Frequency 頻率
Conduit 導管、水管
Pipe 管道、氣管
Echo 回聲
Symmetry 對稱
Interference 幹擾
Prototype 原型
Laboratory 實驗室
Stud 立柱
Gypsum 石膏
Plasterboard 石膏板
互動問答
本期：迷你數獨
每個謎題都由一個在不同位置給與提示數字的4x4或6x6網格組成。遊戲的目的是將空方格填上數字1到4（對於4x4大小的謎題）或者1到6（對於6x6的謎題），使得每一行，每一列以及每一個宮都沒有重複的數字出現。
本期難度：Diabolical
（答案見下期）
註：數獨是一種源自 18 世紀末的瑞士數學家歐拉所創造的拉丁方塊遊戲。傳數獨源起於拉丁方陣（ Latin Square ）， 1970 年代在美國發展，改名為數字拼圖（ Number Place ）、之後流傳至日本並發揚光大，以數學智力遊戲智力拼圖遊戲發表。在 1984 年一本遊戲雜誌《パズル通信ニコリ》正式把它命名為數獨，意思是「在每一格只有一個數字」。後來一位前任香港高等法院的紐西蘭籍法官高樂德（ Wayne Gould ）在 1997 年 3 月到日本東京旅遊時，無意中發現了。他首先在英國的《泰晤士報》上發表，不久其他報紙也發表，很快便風靡全英國，之後他用了 6 年時間編寫了電腦程式，並將它放在網站上，使這個遊戲很快在全世界流行