基于三目偏振相机的天空偏振模式探测试验装置

Experimental device for detecting the sky polarization mode based on three-lens polarization camera

为提高天空偏振模式探测的稳定性,该文通过分析天空偏振光分布模式和Stokes矢量解析模型,设计了一种基于三目偏振相机的天空偏振模式探测试验装置。该装置克服了传统的天空偏振模式探测装置低效和密封性差的问题,适用于雨天和海面的偏振光探测工作。三目偏振相机的偏振角度为0°、60°、120°,通过求解Stokes矢量解可求出目标观测点处的偏振度(degree of polarization,DOP)和偏振方位角(angle of polarized elevation,AOE),分析了天空偏振模式图中AOE和DOP的分布规律。实验结果表明DOP和AOE关于中性点呈有规律的对称分布,该装置能有效探测天空偏振模式,为偏振导航技术提供有力的技术支持。

[Objective]The detection of sky polarization modes is a crucial step in practical applications of polarization navigation.To mitigate the effects of adverse weather conditions on the polarization image acquisition system and protect the polarization camera lens from damage and contamination,a robust and efficient sky polarization mode detection test device has been developed.This paper designs an experimental device for sky polarization mode detection.This device,based on a three-lens polarization camera and equipped with a polarization information processing system,enables real-time and accurate acquisition of atmospheric polarization patterns.Unaffected by rain or poor weather,this device can be used to detect sky polarization patterns in challenging conditions,such as rainy days or over the ocean surface.[Methods]In this study,the experimental device is designed considering three aspects:external device construction,hardware configuration,and software design.A universal ring plays an important role in the test device,ensuring that regardless of the device tilt,the shooting direction of the three-eye camera remains aligned with the sky vertex,thus guaranteeing stable data acquisition.The device adopts a three-channel polarization imaging method to capture the polarization information of the sky.Each polarization channel comprises a polarization device and an optical imaging lens system.The polarization devices in the three channels are arranged at specific polarization angles to each other,with the optical axis direction of the polarizer set to 0°,60°,and 120°.Therefore,only linearly polarized light from these three directions can enter the charge-coupled device(CCD)camera.By analyzing the distribution pattern of sky-polarized light and applying the Stokes vector analysis model,we designed a host computer for the polarization image processing system.Linear polarization images received by the CCD camera from different directions are input into the polarization image processing system to calculate the sky polarization mode diagram of the target region.[Results]Analysis of the sky polarization mode diagram reveals that the angle of polarized elevation is symmetrically distributed with respect to the solar meridian.The direction of the solar meridian depends on the solar azimuth.The degree of polarization(DOP)presents a regular circular distribution around the neutral point,with the DOP gradually increasing from the neutral point.The distribution of the sky polarization pattern is closely related to the sun’s altitude angle.As the sun’s altitude angle increases from small to large and then decreases,the DOP follows a similar pattern,reaching its minimum value at noon.This suggests that in the morning or evening,when the sun’s altitude angle is small,the DOP is large.Conversely,at noon,when the sun’s altitude angle is at its peak,the DOP is small.[Conclusions]Our experimental results demonstrate that the sky polarization pattern detection test device designed in this study successfully mitigates the influence of complex changes and adverse weather conditions.It not only protects the hardware system of image acquisition but also enhances the stability of the polarization image acquisition system.With its impressive real-time performance and robustness,this device can accurately detect and simulate the sky polarization mode of the local observation point in real time through the upper computer of the sky polarization detection system.The device remains unaffected by uneven terrain and landforms.Its excellent sealing and water-resistance properties further ensure the stability of its measurement outcomes.The device provides substantial technical support for polarization navigation and remote sensing technology in complex environments.