Machine vision systems find a wide range of applications, including self-driving cars, object detection, crop monitoring, and smart cameras. This view is often inspired by the view of biological organisms. For example, human and insect vision have inspired terrestrial artificial vision, while fish eyes have given rise to aquatic artificial vision. Although progress is remarkable, current artificial visions suffer from some limitations: they are not suitable for imaging terrestrial and underwater environments, and are limited to a hemispherical field of view (FOV) (180°).
To overcome these problems, a group of researchers from Korea and the United States, including Professor Young Min Song of the Gwangju Institute of Science and Technology in Korea, have now designed a new machine vision system with an ability to omnidirectional imaging, which can work in both aquatic and aquatic environments. terrestrial environments. Their study was made available online on July 12, 2022 and published in Nature Electronics on July 11, 2022.
“Bio-inspired vision research often leads to new development that did not exist before. This in turn enables a deeper understanding of nature and ensures that the developed imaging device is both structurally and functionally effective” , says Professor Song. explaining his motivation behind the study.
The inspiration for the system comes from the fiddler crab (Uca arcuata), a semi-terrestrial crab species with amphibious imaging capability and a 360° FOV. These remarkable features result from the ellipsoidal eye stalk of the fiddler crab’s compound eyes, which enable panoramic imaging, and flat corneas with a graded refractive index profile, which enable amphibious imaging.
Consequently, the researchers developed a vision system consisting of a planar microlens array with a graded refractive index profile that was integrated into a flexible comb-shaped silicon photodiode array and then mounted in a spherical structure. The graded refractive index and flat surface of the micro-lens were optimized to compensate for blurring effects due to changes in the external environment. Simply put, light rays traveling in different media (corresponding to different refractive indices) were made to focus at the same point.
To test the capabilities of their system, the team performed optical simulations and imaging demonstrations in air and water. Amphibious imaging was performed by submerging the device halfway in water. To his satisfaction, the images produced by the system were clear and free of distortions. The team also demonstrated that the system had a panoramic field of view, 300o horizontal and 160o vertical, in both air and water. In addition, the spherical holder was only 2 cm in diameter, making the system compact and portable.
“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,” speculates Professor Song excitedly.
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Materials provided by GIST (Gwangju Institute of Science and Technology). Note: Content can be edited for style and length.