FY-3气象卫星MERSI数据快速预处理的IDL实现

作为新型卫星数据源,FY\|3/MERSI(风云三号中分辨率光谱成像仪)影像的快速预处理方法与模块目前较少见。采用基于三角网的几何校正算法,根据研究区Shapefile文件和FY\|3/MERSI自带定位数据提取处理区域,实现对应区域全部20个通道几何校正,并利用后向映射重采样输出各通道图像纠正后像元点DN值,随后进行辐射定标、太阳高度角订正等预处理。该系列过程用IDL编写相关程序实现了用户界面化交互操作。运行结果表明:设计的算法流程占用内存小,计算速度快。对于一个面积约45万km²的区域,所有通道处理耗时仅450 s,且校正后影像质量和精度均较好。相较于相同区域借助ENVI软件下地理位置查找表法(GLT)仅实现单通道几何校正耗时超30 min,本文开发的模块大大提高了FY\|3/MERSI数据处理效率,为其在城市热环境、积雪等领域的应用做好准备工作。

Fast Pre-processing of MERSI Data on FY-3 Meteorological Satellite Using IDL

As a source of new satellite data,Medium Resolution Spectral Imager(MERSI) on board the second Generation Polar-Orbiting Meteorological Satellite of China(FY-3) is not only featured with its finer surface-observing ability,but also its multi-channel and huge amount,which takes too much time and frequent I/O operation to correct by Commercial RS software.This paper proposes a flowchart to fast pre-process FY-3/MERSI data,the key steps of that are,according to the study area’s shapefile and FY-3/MERSI self-positioning data,the corresponding region images of all 20 channels are georeferenced using geometric correction algorithm based on triangular network,followed by radiometric calibration,solar elevation angle revision,and so on.The series of procedures are implemented based on IDL program,and realize module interface for user interaction.Test results show that the algorithms in this module take less memory and improve the efficiency of FY-3/MERSI data processing greatly,for an area of about 450 000 km2,it takes only 450 s for all channels,significantly faster than using geographic lookup table(GLT) algorithm in ENVI software to achieve geometric correction,which takes over 30 min for only one channel.Besides,the quality and geographic accuracy of the corrected images are better.The development of this module greatly enhances FY-3/MERSI data processing efficiency,and it completes the prerequisite work for FY-3/MERSI application in thermal environment,snow and other various fields.