They created a dome light cone about 20mm in diameter and sporting 169 microlenses on its surface, each with a radius of about 1mm. The conical structure also integrated of a lot of optical fibre wires, 6μm in diameter, and object image capture was combined with a purposely developed algorithm. Because the fields of view of adjacent microlenses overlap in the same way that ommatidia do for most insects, the compound eye obtained can detect objects from a 90º field of view.
The work was presented in the Optics Letters in a paper titled “Detection of three-dimensional trajectory of object based on curved bionic compound eye”, evaluating together the effect of the illumination intensity, the position of the target’s center, and the non-repeatability and reporting a relative standard uncertainty in 3D positioning at only 8.6%.
“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,” explained Le Song, a member of the research team. “This motion-detection method requires less information, allowing the insect to quickly react to a threat.”
One of the challenges in making an artificial compound eye is that image detectors are flat while the surface of the compound eye is curved. Placing a light guide between the curved lens and an image detector allowed the researchers to overcome this challenge while also enabling 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,” explained Song.