Abstract:

A major difference between insect vision and that of humans or standard computer vision systems is that insects are sensitive to the polarisation pattern of skylight, and also to the near-UV range of the electromagnetic spectrum. In this paper, we describe a bio-inspired imaging system that allows us to assess to what extent these features could potentially be used for autonomous robot navigation. We first establish that a low-resolution omnidirectional system incorporating a near-UV camera and a linear polariser - a simulacrum of the dorsal rim area of the insect compound eye - can resolve the clear sky natural polarisation pattern with sufficient accuracy to allow its use as a navigational tool. We then extend the bio-mimicry by incorporating an additional RGB camera, allowing us to utilise the full range of the insect's visual spectrum. This enables us to capture and investigate the visual cues insects are employing for flight control and navigation, and paves the way for incorporating a similar system in an autonomous mobile robot. Additionally, we present a robust method for estimating sun position based on the polarisation pattern and thus confirm the utility of the system as a sky compass.