Improved Models of Imaging of Skylight Polarization Through a Fisheye Lens

Abstract

Researchers have found that some animals can use the skylight polarization pattern for navigation. It is also expected to use the skylight polarization pattern for human navigating in the near future. However, the challenge is that the need for a more accurate and efficient model of the imaging of skylight polarization is always felt. In this paper, three improved models of imaging of skylight polarization are proposed. The proposed models utilize the analysis of the distribution of the skylight polarization pattern after the polarization imaging system. Given that the skylight polarization pattern after the polarization imaging system is distorted, the focus of this paper is on the degree of distortion of the skylight polarization pattern in these imaging models. Experiments in clear weather conditions demonstrate that the proposed model operates close to the actual acquired skylight polarization pattern.

Design and calibration model of a bioinspired attitude and heading reference system based on compound eye polarization compass

“…The camera-based polarization sensor has the features of large visual fields, and better environmental adaptability. In the last decade, there are abundant studies on the camera-based polarization sensor design [18] and the methods of obtaining compass information [19,20]. For example, a novel polarization sensor integrated with three cameras is designed.…”

“…k 9 = ±1 can be determined by the initial polarization vector measured by the m 9 . Measurement Model: on the basis of the principle that the dot product is invariant under rotation, both the angles between the Sun vector and the gravity vector in n-frame and b-frame are the same, the measurement can be obtained as: According to (20), the measurement model can be expressed as:…”

“…,m 9 , as shown in (6). Subsequently, both Z real shown in (20) and Ĉb m 9 obtained in step (a) are utilized to establish the calibration measurement model II, as given by (21). Finally, UKF is used to estimate the γi 1 , γi 2 , γi 3 as well.…”

Sensor Modeling and Calibration Method Based on Extinction Ratio Error for Camera-Based Polarization Navigation Sensor

“…The azimuth of polarization (AOP) of the sensor can reach up to 0.3256° accuracy [ 24 , 25 ]. Sun et al proposed three improved models of imaging and analyzed different polarization pattern distortion degrees of these imaging models [ 26 ]. Zhao et al proposed a polarization imaging algorithm containing a pattern recognition algorithm and one orientation measurement algorithm to reduce the computational load.…”

“…As such, the light intensity of the two orthogonal channels could be unified with the aid of extinction ratio coefficient. Unlike the existing polarization sensor model [ 26 , 28 , 29 ], a model with extinction ratio parameter was considered as a fine structure model. Moreover, the effect of extinction ratio error on the sensor was carefully analyzed.…”