Researchers at the Gwangju Institute of Science and Technology have developed an amphibious artificial vision system with a panoramic field-of-view capable of imaging both land and underwater environments.
Artificial vision systems are valuable for a large variety of applications, such as self-driving cars, smart cameras, crop monitoring and object detection.
Overcoming limitations in current artificial vision systems
These systems are typically inspired by the vision of biological organisms. For example, the development of terrestrial artificial vision has taken inspiration from human and insect vision. Meanwhile, the aquatic artificial vision has emerged as a result of studying fish eyes. While significant advancements have been made in this field, conventional artificial vision systems have shortcomings. One major limitation is that they are not built to image both land and water environments and are often restricted to a hemispherical (180°) field of view.
In order to conquer these limitations, a team of scientists from Korea and the US, including Professor Young Min Song from Gwangju Institute of Science and Technology in Korea, has created a novel artificial vision system with an omnidirectional imaging ability, which can be capable of imaging both aquatic and terrestrial environments.
The group’s study has been published in Nature Electronics.
“Research in bio-inspired vision often results in a novel development that did not exist before. This, in turn, enables a deeper understanding of nature and ensure that the developed imaging device is both structurally and functionally effective,” explained Professor Song.
Taking inspiration from nature
The motivation behind the team’s system has derived from the fiddler crab (Uca arcuata), a semiterrestrial crab species with amphibious imaging ability and a 360° field of vision. These extraordinary features are a consequence of the ellipsoidal eye stalk of the fiddler crab’s compound eyes, allowing for panoramic imaging and flat corneas with a graded refractive index profile, permitting for amphibious imaging.
Consequently, the team established an artificial vision system comprising an assortment of flat micro-lenses with a graded refractive index profile that was integrated into a flexible comb-shaped silicon photodiode array and then mounted onto a spherical structure. The graded refractive index and the flat surface of the micro-lens were enhanced to counteract the defocusing effects that emerge due to changes in the external environment. This means that light rays travelling in various mediums (corresponding to different refractive indices) were made to focus at the same spot.
Amphibious imaging
In order to examine the abilities of their system, the researchers conducted optical simulations and imaging experiments in air and water. Amphibious imaging was accomplished by immersing the device halfway in the water. Through this, the scientists discovered that the images generated by the system were clear and free of distortions. As well as this, the group demonstrated that the system had a panoramic visual field, 300° horizontally and 160° vertically, in both air and water. Furthermore, the spherical mount was only 2cm in diameter, making this novel system compact and portable.
“Our vision system could pave the way for 360° omnidirectional cameras with applications in virtual or augmented reality or an all-weather vision for autonomous vehicles,” concluded Professor Song.
