基于高阶统计特征的FY-2气象卫星全视场杂散光估计

在分析FY 2VISSR杂散光成因的基础上,对其中的主要部分,即折镜直接反射形成杂散光的物理过程进行了建模。提取了特定区域目标的高阶统计特征,通过对地球圆盘外区域杂散光特征的学习,得出了系统杂散光作用矩阵A的总体最小二乘解,并将其推广到地球圆盘区域内,得到了在该模型下对全视场杂散光的有效估计。分析结果表明:对于红外和水汽通道而言,地球圆盘区域外的杂散光反演误差均值小于1bit,可见光通道反演出的杂散光日变化相对稳定,且各通道去除杂散光后图像的目视效果有了很大的改观。该估计方法有望在近期进入FY 2B及其后续卫星的业务运行中。

Full-field-of-view stray light estimation for FY-2 meteorological satellite based on the high-order statistical eigenvalues

Based on the analysis for the principle of the stray light of the FY-2 meteorological satellite, the main component of the stray light, generated from the folding mirror direct reflections, is physically modeled. By learning the pre-known knowledge of the stray light outside of the earth region as well as extracting the high-order statistical eigenvalues of the designated objective areas, the stray light function matrix A can be calculated using the total least squares (TLS) method, which is applied to the inside of the earth region, and the full-field-of-view (FFOV) stray light estimation can be produced efficiently in the end. It is shown that the mean restoration errors of the stray light outside of the earth region of the IR and WV channels are less than 1 bit, while the daily trend of the restored stray light of the VIS channel is relative stabilization, and the stray-light-free images of all channels are better in sight. The estimation method will be used in the operations of the FY-2 and its subsequences in the near future.