新型芯片產生新視力
For decades, scientists and eye doctors have been trying to develop artificial eyes that would return the sense of sight to blind and visually impaired people. And the thought of the "bionic eye" may not be too far fetched. Many companies, such as Optobionics in Wheaton, Ill., have taken the first steps with tiny microchips that can mimic certain parts and function of the human eye; such as the rods and cones, sensors that convert light into electrical impulses at the retina located at the back of the eye. But scientists at the Office of Naval Research in Arlington, Va., believe they are on the path to a chip that could truly mimic the entire nerve system of the retina back of the human eye. At the heart of their potential artificial eye is a well-known chip design called a cellular nonlinear network, or CNN. In the chip, individual computer circuits are connected to each other in a checkerboard array. Each connection can be given a mathematical "weight" that "describes" the relationship of each circuit to each other. When the chip is exposed to image data, each pixel or point of light in the picture is sent to a specific cell in the chip. Mathematical algorithms can then manipulate each connection's weight to produce different resulting images. One set of algorithms could help find the edges of an object in the image. Another set of algorithm could then find corners, while another set define contours. 數十年來，科學家和眼科醫生壹直努力研制人造眼球，以使盲人和視力受損者重見光明。如今，研制這種"仿生眼"的理想可能不久就會夢想成真。如伊利諾州Wheaton的"視力仿生" 等許多公司已經邁出了第壹步，他們研制的微型芯片能夠模擬人眼的某些部分和功能，如模擬眼睛的視桿細胞和視錐細胞，它們是位於人眼內層視網膜上的感光細胞，可以將光轉變為電脈沖訊號。位於弗吉尼亞州阿靈頓市海軍研究所的科學家們認為，他們很快就能研制出壹種可以真正模擬人眼視網膜整個神經系統的芯片。他們即將推出的人造眼球的核心是壹種頗有名氣的芯片，該芯片被稱為"多孔非線性網絡"，簡稱CNN。在此芯片中，單個計算機電路以棋盤陣列相互聯接，將每次聯接做數學"加權"，就可以 "描述"出電路之間的關聯。當芯片接觸到影像數據時，畫面中的像素或光點就被送入芯片中特制的小格內，然後，數學算法能夠操作每次聯接的權數，由此產生各異的影響。壹套算法能有助於影像中某個物體的邊，而另壹套算法可以找到物體的角，其間，還有壹套算法可以定出物體的輪廓。 Larry Cooper, the program manager at Office of Naval Research who specializes in nanoelectronics, says the CNN chip has multiple advantages that make it ideal for use in an artificial retina. For one, the connections between each circuit are parallel, or "non-linear." That means, the calculation for each circuit is happening almost simultaneously and allows for very rapid image processing. "The time it takes a chip to [process a function] is about a microsecond," says Cooper. 海軍研究所的項目經理Larry Cooper是毫微電子學專家，他說，CNN芯片有眾多優點，用於人造視網膜非常理想。優點之壹就是，每條電路之間的聯系是平行或"非線性"的，這就意味著對每條電路的計算幾乎同時進行，使影像處理瞬間完成。Cooper說："該芯片[完成壹個功能]只需壹微秒。
" Another advantage: The chip is an analog processor. Common microprocessors, such as those used in desktop PC are digital; dealing with values of "1" and "0." But the CNN chip can perform its calculations using image values that aren't as exacting; which is the same way our brain processes information. 另壹個優點是：該芯片是壹種模擬處理器。普通的微處理器處理數值"1"或"0"，如臺式個人電腦中所用的微處理器就是數字的，而CNN芯片可以對不很精確的影像值來進行計算，與人類大腦處理信息的方式相同。 Would It Work? 人造眼球能行嗎？ How the CNN chip could be used as an artificial eye, however, is still fairly theoretical, says Frank Werblin, a professor of neurobiology at the University of California at Berkeley. Werblin, who has conducted his own research in CNN chips, says the ideal use would be to create a three-dimensional array where each layer of CNNs would mimic a specific layer of sensors in the human eye. One layer, for example, would be able to pick out edges, while another picks out color. And while the algorithms for doing such CNN calculations are well known, Werblin says the problem is figuring out how to connect it all with the human brain. "You have a million optic nerve fibers leaving your eyes, and each goes to specific part of the brain's cortex," says Werblin. But he says no one knows just how many or exactly which ones are needed to produce an image that could be understood by the brain. 但是加利福尼亞大學伯克萊分校神經生物學教授Frank Werblin說， CNN芯片人造眼球的運用目前還處於理論研究階段。Werblin本人也從事CNN芯片研究，他說理想的應用應該是建立壹種三維的列陣，使每層CNN芯片能分別模擬人眼相應壹層的感光細胞。例如某壹層的CNN芯片能夠辨認出物體的邊緣，而另壹層能辨別出色彩。Werblin說，大家都知道做CNN計算的算法，但問題是要想辦法將所有這壹切與人腦相接。Werblin說："人眼有上百萬根視神經纖維，每壹根都通向大腦皮層某壹特定位置。"他說，但是無人知道需要多少或哪些視神經纖維才能產生人腦所能理解的影像。 And there's still the question of how to connect silicon chips to human nerve cells，a process that's just being tried out with much simpler chips such as Optobionic's artificial light sensors. David McComb, chief information officer with Optobionics, says the company has successfully implanted the microchips into the retinas of six patients under a clinical trial approved by the Food and Drug Administration. However, actual results of how well the chips are working probably won't be released for review by other scientists until later this year. 還有壹個問題就是如何將矽芯片與人的神經細胞相連接，現在研究人員正在用諸如 "視覺仿生"人工光感器等更為簡單的芯片嘗試這壹連接過程。"視覺仿生"公司的首席信息官David McComb說他們已經成功地將這種微芯片植入6位患者的視網膜中，這次臨床試驗得到美國食品和藥物管理局的批準。但是這些植入芯片的真實功效要到今年年底才能公布，供其他科研人員研究。 And according to both Werblin and Cooper, it will still be quite some time before CNN chips could be implanted in humans - if ever. Right now, most CNN chips are just too big - about 1 or 2 square inches ; and require too much power to be embedded in an eye. Still, the potential prospects of ending blindness through artificial eyes grows brighter every day. 據Werblin和Cooper介紹，CNN芯片最終植入人眼還要等相當長的壹段時間。目前大多數CNN芯片太大，約有1或2平方英寸，眼內需存入的電量也太大。盡管如此，靠人造眼球重見光明的前景正日益明朗。 " Couple of years ago, every one thought this was pie-in-the-sky, Star Wars stuff," says Dr. Gerald Chader, an ophthalmologist and chief science officer for the Foundation Fighting Blindness. But with more clinical trials and research, Chader says it's quite possible that some form of chip implants will be helping to improve failing eyes in five to 10 years. "In the last couple of years there has been progress," he says, "We have a great deal of hope that there will be positive outcomes." "抗盲基金會"的首席科學官員和眼科學家Gerald Chader博士說："幾年前，人人都認為靠人造眼球復明簡直是異想天開。"但是隨著越來越多的臨床試驗研究的開展，Chader說，在未來5到10年內，某種形式的芯片植入物很可能有助於改善視力受損病人的狀況。他說："在過去的幾年內，這方面已取得進展，我們對未來的成就寄予很大的希望。