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多角度偏振成像仪是一种超广角画幅式的偏振成像传感器,杂散光是影响其辐射偏振测量精度的重要因素之一。为了避免杂散光影响高精度定量参数的反演,需要在实验室对其进行专门的分析、测量和校正。根据多角度偏振成像仪的光学系统特点,将影响仪器的杂光分为局部杂光和全局杂光,重点分析了这两种杂光的成因和表现特性,并以此为基础构建了仪器的杂散光模型,提出了通过分区域照明获取杂光系数矩阵并对待校图像进行分块校正的方法。在未饱和及过饱和两种情况下,通过分矩形区域、分视场二维转动扫描成像的方式,建立了目标区辐射量和其他非目标区杂光量的关系,最终获得11×11区域的杂散光系数矩阵。最后根据实测得到的杂散光系数矩阵对图像进行了校正,结果表明,此校正方法可以消除至少90%的杂散光。
Multi-angle polarimetric imager is an ultra-wide-angle polarizer imaging sensor. Stray light is one of the important factors affecting the measurement accuracy of radiation polarization. In order to avoid stray light from affecting the inversion of high-precision quantitative parameters, it needs special analysis, measurement and correction in the laboratory. According to the characteristics of the optical system of multi-angle polarimetric imager, the stray light affecting the instrument is divided into local stray light and global stray light. The causes and performance characteristics of the two stray light are analyzed emphatically. Based on this, Stray light model, the method of obtaining stray light matrix by subarea illumination and correcting the image to be corrected by block is proposed. Under the condition of not saturated and supersaturated, the relationship between the radiation amount in the target area and the amount of other non-target area stray light is established by dividing the two-dimensional rotational scanning image of the rectangular field and the sub-field of view, and the final 11 × 11 Stray light coefficient matrix. Finally, according to the measured stray light coefficient matrix, the image is corrected. The results show that this method can eliminate at least 90% of the stray light.