HKUST bioinspired compound eye set to enhance robot vision

14 Aug 2024

Lens-free pinhole structure gives wide field of view and motion-tracking capabilities.

A project at the Hong Kong University of Science and Technology (HKUST) has demonstrated an artificial compound eye that the team believes could revolutionize robot vision.

Described in Science Robotics, the new system "is not only more cost-effective, but demonstrates a sensitivity at least twice that of existing market products in small areas," said the project.

HKUST took inspiration from the natural world, adding its device to the list of breakthroughs recently made in vision systems modeled on a variety of eyes from the animal kingdom.

Previous examples have seen the optics of insects and animals applied to applications in cancer treatment, multispectral object detection and other fields where novel imaging capabilities are valuable.

The compound eyes of insects hold particular appeal, as they can feature wide field of view and motion-tracking ability, a desirable combination for industrial applications and responsive robot vision systems.

But integrating compound eye systems into autonomous platforms like robots or drones has been challenging. These systems often suffer from issues related to complexity and stability during deformation and geometry constraints, as well as potential mismatches between optical and detector components, according to HKUST.

"Previous attempts that transferred a microlens array onto a curved surface have suffered from complications during the transfer process," noted the project in its published paper.

"As an alternative approach, HKUST developed a lens-free compound eye by combining a three-dimensionally printed honeycomb optical structure with a hemispherical, all-solid-state, high-density perovskite nanowire photodetector array."

A huge boost for robotics applications

In this design the hemispherical array imager can feature a high pixel density to enlarge the imaging field. while the 3D-printed lens-free pinhole array can have a customizable layout to regulate incident light and eliminate the blind area between neighboring ommatidia - the individual units within an insect’s compound eye.

In trials the combination of good angular selectivity, a wide field of view, wide spectrum response in monocular and binocular configurations and dynamic motion tracking capability allowed the pinhole compound eye not only to locate targets accurately but also to track a moving quadruped robot in real time, after the imager was incorporated onto a drone.

This kind of tracking exercise and the following of moving targets indicate that the new compound eye could be particularly valuable for advanced robotic vision systems, commented HKUST. If the team can further miniaturize the device size and increase the number of ommatidia it features, then enhanced imaging resolution and response speed could then be exploited in a number of robot vision scenarios.

"This compound eye design is simple, light and cheap," commented Zhiyong Fan from HKUST. "Although it won’t fully replace traditional cameras, it could be a huge boost in certain robotics applications, such as in a swarm of drones flying in close formation."

HKUST video