Researchers Create Compound Eye Based on Insects

Researchers from Tianjin University in China have developed a newly created biologically inspired compound eye. It will be used to help scientists gain a better understanding of how insects use their compound eyes to sense objects and trajectories extremely fast. The researchers are also looking at how to use it with a camera to create 3D location systems for robots, self-driving cars, and unmanned aerial vehicles. 

The new bio-inspired compound eye was reported in the Optical Society (OSA) journal Optics Letters. It both looks like an insect as well as works like one. The compound eyes of insects consist of hundreds to thousands of ommatidia, or repeating units. Each one of them act as a separate visual receptor. 

Le Song, a member of the research team, spoke on the new project. 

“Imitating the vision system of insects has led us to believe that they might detect the trajectory of an object based on the light intensity coming from that object rather than using precise images like human vision,” Le Song said. “This motion-detection method requires less information, allowing the insect to quickly react to a threat.”

The researchers created 169 microlenses on the surface of the compound eye through a method called single point diamond turning. The microlens had a radius of around 1mm, and this created a component that was about 20mm. It was able to detect objects from a 90-degree field of view. 

One of the issues that researchers run into when creating a compound eye is that image detectors stay flat while the surface of the compound eye is curved. They got around this by placing a light guide between the curved lens and an image detector. By doing this, the team was able to enable the component to receive light from different angles uniformly. 

“This uniform light receiving ability of our bio-inspired compound eye is more similar to biological compound eyes and better imitates the biological mechanism than previous attempts at replicating a compound eye,” said Song.

When it comes to measuring 3D trajectory, the researchers put grids on each eyelet of the compound eye to help detect location. LED light sources where then placed at different distances and directions. The compound eye used an algorithm to calculate the 3D location of the LEDs using the location and intensity of the light. 

The compound eye was able to detect the 3D location of an object very rapidly. The one issue was that when the light sources were far away, the location accuracy became reduced. This could be the reason that most insects are nearsighted. 

“This design allowed us to prove that the compound eye could identify an object's location based on its brightness instead of a complex image process,” said Song. “This highly sensitive mechanism suits the brain processing ability of insects very well and helps them avoid predators.”

The researchers believe that because this new compound eye can detect an object’s 3D location, it could be used for small robots that require fast detection from lightweight systems. This new technology can also help scientists better understand insects. 

The next step for the scientists is to put the localization algorithm into different platforms, like integrated circuits, so that the system can be used in other devices. They also want to be able to mass produce the compound eyes in order to reduce the cost.