多角度偏振成像仪高精度辐射定标方法

High-Precision Radiometric Calibration of Directional Polarization Camera

开展高精度辐射定标方法研究,对于多角度偏振成像仪实现大气气溶胶粒子分布和微观物理特性探测反演的科学应用至关重要。采用傅里叶级数的分析方法,建立了全视场起偏度的测量模型,消除了参考光源偏振方位角绝对位置引入的测量误差,实现了光学系统偏振特性的准确测量。结合多角度偏振成像仪的辐射与偏振定标模型,开展了光学系统偏振特性的校正方法研究,实现偏振特性引起辐射定标不确定度由8%下降至2.2%以内。利用高精度二维转动平台和大口径积分球辐射源,采用分视场测量方法,校正像元响应非一致性,实现相对辐射校正精度优于0.5%。采用基于标准灯漫反射板的辐亮度量值传递链路,经过各影响因素的分析评测,所有波段辐射定标精度均优于5%。

Radiometric calibration of the directional polarization camera(DPC) with high-precision is very important for quantitative scientific application of acquiring an accurate description of aerosol distributions and microphysical properties. Using Fourier series analysis method, a polarization rate measurement model is established to eliminate the measurement error introduced by the absolute direction in the angle of linear polarization of the reference light source,so that the polarization property is measured with high accuracy. Combining radiometric and polarimetric calibration model of DPC, radiometric calibration uncertainty caused by polarization property decreased from 8.8% to 2.2% after correction. Using an integrating sphere light source with large aperture and high-precision two-dimensional turntable platform, adopting sectional viewing field measurement method, the entire pixels response non-uniformity is measured and corrected, and the precision of relative radiometric calibration coefficient is better than 0.5%. To transfer the spectral radiance value, the standard lamp and diffuse reflection reference board system is introduced. According to analysis and evaluation of various factors, radiometric calibration accuracy of the entire waveband is better than 5%.