多角度偏振成像仪探测器非均匀性校正研究

Research on Non-uniformity Correction of Detector for Directional Polarimetric Camera

像面非均匀性与镜头、探测器组件、空间杂散光、温漂等多种因素相关,单一方法无法有效区分误差源,需逐一校正,针对偏振成像仪通过积分时间调整的在轨工作模式,研究基于多参量校正补偿的探测器非均匀性校正方法.通过探测器综合测试设备,获取温度、暗电流、曝光时间、光谱响应率等敏感因素数据,经过暗电流、帧转移效应、温度补偿和环境参量的校正,对探测器非均匀性进行多点法校正,消除了像面低频不均衡响应差异和邻域高频差异.实验表明,95%满阱单帧数据像元响应不一致性由1.141%降至0.513%,校正后数据噪声表现为散粒噪声,校正后有良好的动态范围调节能力和线性度,基于多参量的非均匀性校正方法为仪器的定标校正和在轨快速计算提供了数据支撑,为后续偏振遥感仪器提供有效参考.

The image non-uniformity is related to many factors such as lens,detector assembly,spatial stray light,etc.The single correction method can not distinguish the error source effectively.In view of the on orbit working mode of polarization imager based on integral time adjustment,the non-uniformity correction method of detector based on multi parameters is studied.Through the comprehensive test equipment of CCD detector,the datas of sensitive factors such as temperature,dark current,exposure time and specrtal response are obtained.After a seris of preprocessing of the image including removal of darkness signal,removal of smearing effect and temperature conpenstion,the low-frequency unbalanced response difference of the image surface is eliminated,and the high-frequency difference is effectively suppressed.The experimental results show that the photo response non-uniformity of 95%full well single frame data is reduced from 1.141%to 0.513%.After correction,the data noise is shown as shot noise.After correction,the detectorhas good dynamic range adjustment ability and linearity.The nonuniformity correction method based on multi parameters is used to provide data support for calibration correction and on orbit fast calculation of the instrument,and provide effective reference for the following polarization remote sensing instruments.