Novel robust skylight compass method based on full-sky polarization imaging under harsh conditions

Abstract

A novel method based on Pulse Coupled Neural Network(PCNN) algorithm for the highly accurate and robust compass information calculation from the polarized skylight imaging is proposed,which showed good accuracy and reliability especially under cloudy weather,surrounding shielding and moon light. The degree of polarization (DOP) combined with the angle of polarization (AOP), calculated from the full sky polarization image, were used for the compass information caculation. Due to the high sensitivity to the environments, DOP was used to judge the destruction of polarized information using the PCNN algorithm. Only areas with high accuracy of AOP were kept after the DOP PCNN filtering, thereby greatly increasing the compass accuracy and robustness. From the experimental results, it was shown that the compass accuracy was 0.1805° under clear weather. This method was also proven to be applicable under conditions of shielding by clouds, trees and buildings, with a compass accuracy better than 1°. With weak polarization information sources, such as moonlight, this method was shown experimentally to have an accuracy of 0.878°.

Orienting to polarized light at night—matching lunar skylight to performance in a nocturnal beetle

“…On all moonlit nights, the highest degree of polarization was measured in a band at approximately 90 deg from the moon (Fig. 2), mimicking that of the sunlit sky (Berry et al, 2004;Horváth et al, 2014), as found for previous studies of the polarization of lunar skylight (Gál et al, 2001;Kyba et al, 2011;Barta et al, 2014;Tang et al, 2016). Although the serial-imaging protocol we employed can lead to the accumulation of motion artefacts, particularly during long exposures, these effects appeared to be limited, for the most part, to a small number of bright stars ( Fig.…”

Orienting to Polarized Light at Night—Matching Lunar Skylight to Performance in a Nocturnal Beetle

“…On all moonlit nights the highest degree of polarization was measured in a band at approximately 90° from the moon (Fig. 2), mimicking that of the sunlit sky (Berry et al ., 2004; Horváth et al ., 2014), as found for previous studies of the polarization of lunar skylight (Gál et al ., 2001; Kyba et al ., 2011; Barta et al ., 2014; Tang et al ., 2016). Although the serial-imaging protocol we employed can lead to the accumulation of motion artefacts, particularly during long exposures, these effects appeared to be limited, for the most part, to a small number of bright stars (Fig.…”

Aerosol-induced changes in sky polarization pattern: potential hint on applications in polarimetric remote sensing

“…Pomozi, Horvath, and Wehner (2001) revealed that under clear sky conditions, there are also a certain distribution of sky polarization, which could be utilized by insects. Tang et al (2016) developed a new full-sky polarization imaging sensor, which could get relatively high accuracy of angle of polarization (AOP) under harsh condition. Zhang et al (2015) found a new way to simulate the sky polarization signal obtained by compound eyes of Cataglyphis and validated it through navigation experiments.…”