天空散射光偏振成像噪声建模与分析

Noise modeling and analysis of polarization imaging for scattered skylight

仿生偏振导航是近年来兴起的一种新原理导航方式,对天空光进行成像可以获得更为丰富的天空散射光的偏振信息以及分布特征,有利于提高偏振导航传感器的精度和抗干扰能力。根据现有的Stokes参量测量偏振光的原理以及成像装置的噪声模型,对基于Stokes参量法的偏振角度测量噪声进行了建模,并根据模型进行了仿真分析。仿真结果表明:提高相机的信噪比(SNR)能够显著提高偏振成像的质量,当相机的SNR大于44 d B时,天空偏振角度的测量标准差将优于1°/像素;得到了0°,60°,120°和0°,45°,90°检偏器分布模式下对不同偏振角度的入射光测量噪声的统计分布特征。尽管0°,60°,120°的检偏器布置方案相对于0°,45°,90°的检偏器布置方案有着更大的计算复杂度,但在使用相同信噪比相机的情况下,该布置方案的噪声更小。该结论将对天空偏振光成像装置的构建及其误差分析与补偿技术提供参考。

Bio-inspired polarization navigation is a new navigation method. More polarization information and distribution pattern will be gathered through imaging the scattered skylight and it will enhance the precision and anti-interference ability of polarization navigation sensors. The measurement noise of the polarization angle based on Stokes parameters is modeled and the simulation is conducted according to the principle of the polarization measurement of Stroke parameters and the noise model of imaging cameras. The result shows that to enhance the signal-to-noise ratio of cameras will enhance the quality of the polarization imaging significantly. The deviation of the measurement of the polarization angle will better than 1° per pixel when the signal-to-noise ratio is higher than44 d B. The statistical distribution characteristics for different polarization angle incident lights is obtained under the condition that the analyzers is arranged as 0,60°,120° and 0,45°,90°. The measurement noise of the analyzers arrangement of 0,60°,120° is less using the same signal-to-noise ratio cameras though the computational complexity of the arrangement of 0,60°,120°is more complex than the arrangement of 0,45°,90°. The conclusion will be the reference for the construction of the polarization imaging facilities for polarized skylight,its error analysis and compensation technology.