帧转移面阵CCD相机对高亮目标成像时产生的帧转移模糊效应是影响偏振测量精度的关键因素,开展帧转移模糊效应的测量和校正方法研究对提高星载偏振相机高精度定量化应用水平具有重要意义。以GF-5卫星多角度偏振成像仪(DPC)为例,介绍了帧转移模糊效应的产生机理及特点,提出了将帧转移模糊效应分为与光照条件无关的响应差异型帧转移模糊效应和与光照条件有关的拖影型帧转移模糊效应。结合DPC在轨成像时帧转移模糊效应的特点,分别提出了基于矩阵与暗行法的拖影型帧转移模糊效应校正模型和基于暗电流通道的响应差异型帧转移模糊效应校正模型。最后利用积分球验证了响应差异型和拖影型两种类型帧转移模糊效应的最优校正顺序及校正方法的可行性,同时采用太阳光对DPC在轨运行时的帧转移模糊效应校正精度进行验证。实验结果表明,所提方法将DPC帧转移模糊效应对高反射云及太阳耀斑等高亮目标的偏振测量精度的影响由7.28%降至0.43%,满足DPC偏振测量精度优于2%的定标要求。

The frame-transfer blurring effect is a key factor that affects the precision of polarization measurement accuracy of highlight-target imaging via a frame-transfer array CCD camera. To improve the precision of spaceborne polarization cameras, it is of great significance to carry out studies on the measurement and correction method of the frame-transfer blurring effect. Considering the GF-5 satellite directional polarization camera (DPC) as an example, this paper investigates the generation mechanism and features of the frame-transfer blurring effect. The frame-transfer blurring effect is divided into the response-difference type, which is unrelated to the light conditions, and the smear type, which depends on the light conditions. To correct the features of the frame-transfer blurring effect in on-orbit imaging by the DPC, two correction models are proposed: the correction model of smear frame-transfer blurring effect based on the matrix and dark line methods, and the correction model of response-difference frame-transfer blurring effect based on the dark current channel. Finally, the optimal correction sequence and the feasibility of correction by the response-difference and smear frame-transfer blurring effects are verified by an integrating sphere. Additionally, the correction accuracy of the frame-transfer blurring effect in the DPC on orbit is verified using sunlight. Experimental results show that the proposed method reduces the influence of the frame-transfer blurring effect in the DPC on the polarization measurement accuracy of highlight targets, such as high reflective cloud and solar flare, from 7.28% to 0.43%, satisfying the calibration requirement that the DPC polarization measurement accuracy is <2%.