Sep. 23, 2003 A University at Buffalo optical engineer has created a silicon chip that mimics the structure and functionality of an octopus retina.
Called the o-retina, the chip one day may give sight to autonomous robots used in space and undersea exploration or could be used in hazardous environments, like a nuclear reactor or underground pipe, says creator Albert H. Titus, Ph.D., assistant professor of electrical engineering in the UB School of Engineering and Applied Sciences.
Titus's o-retina chip sees the world very much like an octopus -- using brightness, size, orientation and shape to distinguish objects. Like the octopus, the chip cannot distinguish between diagonally oriented, horizontally mirrored images, such as the letter "X." Future implementations of the chip will include polarization sensitivity -- the ability to see polarized light, particularly underwater -- an important aspect of the octopus visual system.
Research on the optical systems of the octopus and other animals provides important clues for the design of artificial vision systems, according to Titus, a leading researcher in the field of optoelectronics. He chose to mimic the octopus retina because it has a simple, yet elegant, visual system that is relatively easy to simulate.
"Different animals have different visual structures with different properties for how they see the world," Titus says. "If we want to develop a chip that can see far distances, we should mimic the visual system of an eagle. If we want to develop a chip for seeing primarily in the desert, we should mimic the eyes of zebras or lions."
Titus's goal is to build a complete artificial vision system capable of performing multiple visual functions. His chips use analog circuitry, which require far less operational power than digital circuitry. Low power consumption makes the chips ideal for use in autonomous robots or other exploration devices that would have long run times, Titus explains.
Titus also is developing an artificial visual system that has a novel approach for performing depth perception. And he has designed a silicon retina chip that mimics edge detection -- a form of data compression performed by biological eyes.
This chip will identify objects by processing visual information from the edges of an image rather than the whole picture. Edge information usually is sufficient for detecting and tracking objects, Titus says.
"Edge detection is a basic level process of what the retina does," he adds. "The retina reduces the amount of visual information we take in and extracts the most useful information.
"The challenge is understanding how the brain uses this information to process and reconstitute the image, then can we implement this process on a chip."
His current work on the o-retina chip and depth perception systems is funded by the National Science Foundation. The optical edge detection chip was described in the August issue of Optical Engineering.
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