A
New Chip Design May Lead to New Sight
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新型芯片产生新视力
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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. |
数十年来，科学家和眼科医生一直努力研制人造眼球，以使盲人和视力受损者重见光明。如今，研制这种"仿生眼"的理想可能不久就会梦想成真。如伊利诺州Wheaton的"视力仿生"
等许多公司已经迈出了第一步，他们研制的微型芯片能够模拟人眼的某些部分和功能，如模拟眼睛的视杆细胞和视锥细胞，它们是位于人眼内层视网膜上的感光细胞，可以将光转变为电脉冲讯号。位于弗吉尼亚州阿灵顿市海军研究所的科学家们认为，他们很快就能研制出一种可以真正模拟人眼视网膜整个神经系统的芯片。他们即将推出的人造眼球的核心是一种颇有名气的芯片，该芯片被称为"多孔非线性网络"，简称CNN。在此芯片中，单个计算机电路以棋盘阵列相互联接，将每次联接做数学"加权"，就可以
"描述"出电路之间的关联。当芯片接触到影像数据时，画面中的像素或光点就被送入芯片中特制的小格内，然后，数学算法能够操作每次联接的权数，由此产生各异的影响。一套算法能有助于影像中某个物体的边，而另一套算法可以找到物体的角，其间，还有一套算法可以定出物体的轮廓。 |
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. |
海军研究所的项目经理Larry
Cooper是毫微电子学专家，他说，CNN芯片有众多优点，用于人造视网膜非常理想。优点之一就是，每条电路之间的联系是平行或"非线性"的，这就意味着对每条电路的计算几乎同时进行，使影像处理瞬间完成。Cooper说："该芯片[完成一个功能]只需一微秒。" |
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. |
另一个优点是：该芯片是一种模拟处理器。普通的微处理器处理数值"1"或"0"，如台式个人电脑中所用的微处理器就是数字的，而CNN芯片可以对不很精确的影像值来进行计算，与人类大脑处理信息的方式相同。 |
Would
It Work? |
人造眼球能行吗？ |
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. |
但是加利福尼亚大学伯克莱分校神经生物学教授Frank
Werblin说，
CNN芯片人造眼球的运用目前还处于理论研究阶段。Werblin本人也从事CNN芯片研究，他说理想的应用应该是建立一种三维的列阵，使每层CNN芯片能分别模拟人眼相应一层的感光细胞。例如某一层的CNN芯片能够辨认出物体的边缘，而另一层能辨别出色彩。Werblin说，大家都知道做CNN计算的算法，但问题是要想办法将所有这一切与人脑相接。Werblin说："人眼有上百万根视神经纤维，每一根都通向大脑皮层某一特定位置。"他说，但是无人知道需要多少或哪些视神经纤维才能产生人脑所能理解的影像。 |
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. |
还有一个问题就是如何将硅芯片与人的神经细胞相连接，现在研究人员正在用诸如
"视觉仿生"人工光感器等更为简单的芯片尝试这一连接过程。"视觉仿生"公司的首席信息官David
McComb说他们已经成功地将这种微芯片植入6位患者的视网膜中，这次临床试验得到美国食品和药物管理局的批准。但是这些植入芯片的真实功效要到今年年底才能公布，供其他科研人员研究。 |
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. |
据Werblin和Cooper介绍，CNN芯片最终植入人眼还要等相当长的一段时间。目前大多数CNN芯片太大，约有1或2平方英寸，眼内需存入的电量也太大。尽管如此，靠人造眼球重见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." |
"抗盲基金会"的首席科学官员和眼科学家Gerald
Chader博士说："几年前，人人都认为靠人造眼球复明简直是异想天开。"但是随着越来越多的临床试验研究的开展，Chader说，在未来5到10年内，某种形式的芯片植入物很可能有助于改善视力受损病人的状况。他说："在过去的几年内，这方面已取得进展，我们对未来的成就寄予很大的希望。 |
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