Future of Engineering

Here's another invention inspired by nature. To be specific, it's the common housefly - Musca domestica's eye that is the muse behind the recently developed fiber optic sensor for robot vision. Although insects are relatively simple organisms compared to vertebrates, they are blessed with a very efficient visual system, which enables them to navigate with great ease and accuracy.



Compound eye of a fly



Let's see what makes insect vision interesting.

Flies possess a visual precision beyond the resolution limit – a property called hyperacuity, which enables them to track and react to situations quickly. Insects have compound eyes that are made up of units called ommatidia.



A detailed diagram of an ommatidium


The housefly's eye contains 4,000 small, simple ommatidia which can be moved at will. Since each ommatidium faces a different direction, the fly is able to see to the front, back, left, right, top and bottom, giving it a 360 degree perspective of the world.

That's not it. Each ommatidium in the eye contains eight photoreceptors. The field of view of each photoreceptor overlaps with up to 90 percent overlap with those next to it.These photoreceptors convert light into ionic current, which then goes into the fly's processing system. The classic theory on insect vision is called the mosaic theory and it suggests that each cell (ommatidia) forms an image of the limited part of the visual field. So, in layman speak, each cell puts together a part of the picture to form the entire object.

So now we know how a house fly views images.It sees the world through thousands of tiny eyes.

The latest development in Robot vision

Now lets see how the researchers from the Naval Air Warfare Center in China Lake, California, and the University of Wyoming were inspired by the fly's vision.

"Unlike conventional image processing systems which are often digital, the fly’s processing system is analog. Digital systems receive data pixel by pixel, and generally require time-consuming, computationally expensive processing. The analog system helps the fly extract edge information much more quickly, and also enables parallel processing. Both these features contribute to the fly’s highly accurate, high-speed vision system.

The researchers designed their sensor to mimic the fly’s overlapping photoreceptors and analog, parallel processing system. The sensor consists of a 1-mm-diameter ball lens that focuses light onto an array of photodetectors, where the field of view overlaps by about 70%. In experiments, the sensor could locate a 1-mm-wide string as the string moved across the field of vision at distances up to 200 mm from the lens, with minimal error. "

Why is this study so interesting?

The study of insect vision is of significant interest to engineers who need inspiration for designing future motion-sensitive smart sensor devices and collision avoidance applications.
The development of this technology can be very helpful in medical, industrial and defence areas.For instance it might be able to provide improvements to unmanned vehicles and industrial inspection robots.

The common housefly, labeled a pest everywhere has revealed the inherent beauty of nature by showing that each and every creature is absolutely unique. All we need is eyes to see and be inspired by it.