Cephalopod eye camera for high contrast imaging under vertically uneven light environments

Abstract

The development of high-performance imaging systems for surveillance, navigation, and monitoring under constantly changing light environments has been a challenging goal. Balancing the uneven light distribution, improving the contrast for object detection, and achieving high visual acuity in target region are key considerations to build such high-quality imaging devices. The cephalopod vision has evolved for high contrast underwater imaging owing to optical properties of wide field of view and polarization recognition. In particular, the eye of cuttlefish exhibits irregular ocular structure, which is specialized for high quality imaging in shallow water through various optical characteristics such as light balancing by a W-shaped pupil, low optical aberrations by a spherical lens and a curved retina, and high-contrast by an unusual photoreceptor cell distribution and polarization-sensitive microvilli on the retina. Here, we report an artificial vision consisting of a W-shaped aperture, a single ball lens, and a cylindrical silicon photodiode array with a designed pixel distribution and a flexible polarizing filter inspired by the cephalopod vision, especially the cuttlefish. The W-shape aperture and ball lens compensates vertically uneven light environment by reducing intense light incident from the upper side. Further, the cylindrical silicon photodiode array with the belt-like pixel distribution and the polarization imaging feature enables high-acuity in target visual region and high-contrast imaging by filtering the polarized light noise. The cuttlefish-eye-inspired artificial camera is expected to create new opportunities in electronics and mobile robotics encountered constantly changing light environments such as vision systems for autonomous vehicles and drones.