To effectively navigate real-world environments, robots typically analyze images collected by imaging devices embedded in their bodies. To improve the performance of robots, engineers are thus trying to develop different types of high-performance cameras, sensors and artificial vision systems.
Many artificial vision systems developed so far draw inspiration from the eyes of humans, animals, insects and fish. These systems have different features and characteristics, depending on the environment in which they are designed to operate.
Most existing sensors and cameras are designed to operate either on land (i.e. in terrestrial environments) or in water (i.e. in aquatic environments). On the other hand, craft-inspired artificial vision systems that can operate in both terrestrial and aquatic environments remain rare.
Researchers at the Institute of Basic Science (IBS), Seoul National University, Gwangju Institute of Science, Massachusetts Institute of Technology (MIT) and the University of Texas at Austin recently created a new vision system inspired by crabs, which it can work both on land and in water. This amphibious system, presented in a paper published in Nature Electronicsallows robots to gain a 360° panoramic view of their environment so they can detect obstacles and navigate environments more efficiently.
“Previous work (including our group’s research) on wide-field-of-view (FoV) cameras has always been at less than 180°, which is not enough for ‘full’ panoramic vision and was not suitable for changing external environments,” he said Young. Min Song, one of the researchers who conducted the study, said Tech Xplore. “We wanted to develop a 360° FoV camera that could image in both air and water.”
Display setting for the crab eye camera. Credit: Lee et al.
The artificial vision system developed by this team of researchers draws inspiration from the eyes of fiddler crabs. This unique species, also known as calling crabs, can get a full bird’s-eye view of its surroundings without having to move its eyes and body. To artificially reproduce the crab’s eyes, Min and his colleagues used a flat camera lens.
“If you use a conventional curved lens for imaging, its focal point changes when you submerge the lens in water,” Song explained. “On the other hand, if you use a flat-surface lens, you can see a clear image regardless of the ambient conditions. The crab that lives in the intertidal area has this kind of flat surface of its lens, and we just imitated that crab-lens. “
To create their sophisticated vision system, the researchers integrated an array of planar microlenses with a graded refractive index and an array of flexible comb-shaped silicon photodiodes into a spherical structure. The microlenses they used can maintain their focal length regardless of changes in the external refractive index between air and water.
“As far as we know, it’s the first time we’ve demonstrated amphibious and panoramic vision systems globally,” Song said. “Our vision system could pave the way for 360° omnidirectional cameras with applications in virtual or augmented reality or all-weather vision for autonomous vehicles.”
Song and his colleagues tested their system in a series of visual simulations and visual demonstrations, taking into account the characteristics of both land and water environments. So far, they have found that it has achieved promising results, so it could soon be tested and applied to many different hybrid and amphibious robots.
“In our next studies we will conduct further engineering to achieve higher resolution and superior imaging performance,” Song added. “In addition, we are still interested in developing a new type of camera with unique imaging features inspired by the eyes of other animals.”
Fiddler Crab eye view inspires researchers to develop new artificial vision More information: Mincheol Lee et al, An amphibian artificial vision system with a panoramic field of view, Nature Electronics (2022). DOI: 10.1038/s41928-022-00789-9
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Reference: A Crab-Inspired Artificial Vision System for Both Terrestrial and Aquatic Environments (2022, August 2) Retrieved August 2, 2022, from
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