Visionary biomimicry: five insects inspiring cutting-edge technology
Biomimicry draws lessons from nature to improve technology. Here are five innovations based on the complex workings of insect eyes.
Biomimicry is a smart way to solve tough problems. Why go to the trouble of thinking up a whole new solution when you can see how living creatures have done it first, using approaches refined over millions of years of evolution?
One area where biomimicry is yielding fascinating results is in the field of optics and machine vision. While our cameras and ways of thinking about sight have largely been informed by the human visual system, cutting-edge research is looking to insects to find new tricks for everything from depth perception to colour analysis. Here are five of the most exciting prospects.
Bees: colour accuracy
The honeybee has three extra eyes on the top of its head. These eyes, known as ocelli, have traditionally been thought to assist in the bee in flight. Research by Australian scientists, however, has shown the eyes play a pivotal role in enabling the bee to accurately assess colour, calibrating for constant changes in ambient light conditions to correctly identify potential food sources.
By mapping the way the ocelli feed information into the key-colour processing areas of the bee brain, where it is integrated with information from the insect’s two main compound eyes, the scientists found a “biologically validated mathematical solution” that could “be readily implemented into artificial systems”. This discovery on colour constancy can be implemented into camera imaging systems to enable more accurate colour interpretation.
Jumping spiders: distance perception
Jumping spiders are masters at judging distances – a necessary skill since their survival depends on leaping on prey. How they judge distance, though, may be unique in the animal kingdom. Humans, for instance, use stereoscopic vision, processing information from two perspectives to assess distance. Other animals bob their heads side to side to exploit an effect called motion parallax. The jumping spider has a capability altogether different, called “image defocusing” by the Japanese scientists who discovered it.
It has a unique retina composed of four tiered photoreceptor layers, each of which focuses different wavelengths of light. The two top layers are sensitive to ultraviolet light and the two deepest layers to green light. Only on the deepest layer, however, does green light focus, with the researchers suggesting the spider gauges depth cues from the amount of defocus in the fuzzy layer. This techhnique may inspire future computer vision and robotic systems.
Flies: field of vision
Flies, like most other insects and some sea creatures, make up for their limited brain power with complex sensory receptors. Their compound eyes consist of hundreds of optical units, known as ommatidia.
The convex hexagonal structure provides nearly 360-degree field of vision – a capability that inspired researchers at Pennsylvania State University in 2014 to create optical sensors and miniature light-emitting devices able to scatter light more uniformly. Using liquid crystals, the Penn State scientists created compound lenses in 2015 able to produce sets of images with different focal lengths, a property that could be used for three-dimensional imaging.
Moth eyes are covered with a water-repellent coating that enables them to see at night while making their eyes among the least reflective surfaces in nature – a useful evolutionary adaptation that minimises their visibility to predators during the nocturnal hours when they are active. The nanostructure of this anti-reflective coating inspired Japanese researchers to replicate it in a film to cover photovoltaic solar cells, improving the efficiency of the cells by reducing the amount of radiation reflected rather than captured.
Extending this idea, a team of scientists in the US and Taiwan have developed a fabrication technique using self-assembled nanospheres to create an anti-reflective film for smartphones and tablets, enabling the screens to be more easily read in bright sunlight. The scientists report their moth-coating reduces surface reflection just 0.23%, compared with the 4.4% reflected by an iPhone.
Dragonflies: visual tracking
Detecting and tracking small objects against complex backgrounds is just one of the capabilities we take for granted but which pose huge challenges for robotics engineers. Human achieve it with neural power; dragonflies, along with other flying insects, manage it despite a brain the size of a grain of rice.
Inspired by the dragonfly’s aerial dexterity, able to chase down prey at speeds up to 60 km/h with a success rate of more than 97%, a team of engineers and neuroscientists at the University of Adelaide developed an algorithm to emulate the insect’s visual tracking. Their “active vision” system works not by trying to keep a target centred in its field of view; instead it locks onto the background and lets the target move against it. The result: performance as good as state-of-the-art target-tracking algorithms but running up to 20 times faster, opening to the path to applications using quite simple processors in bio-inspired autonomous robots.