基于FLAASH模型的Worldview3大气校正

Atmospheric correction of Worldview3 image based on FLAASH model

随着遥感技术的发展,遥感应用已由定性发展至定量阶段,而大气校正是定量遥感研究中不可或缺的重要环节。Worldview3是全球最高空间分辨率的商业多光谱遥感卫星,相较于传统的多光谱遥感数据,该数据在定量遥感方面具有更大的潜力。利用ENVI软件的FLAASH模块对Worldview3进行大气校正,并以新疆罗布泊无人区为例,利用该地区典型地物盐碱地和闪长岩的ASD实测光谱数据对Worldview3大气校正前后的数据进行了评价。首先,将Worldview3的DN值转化为辐射亮度和表观反射率,并利用FLAASH模块对其进行大气校正;然后,计算了研究区典型地物(盐碱地、闪长岩)的辐射亮度、表观反射率值,并把实测的盐碱地和闪长岩的波谱数据重采样到Worldview3相应波段;最后对结果进行了定性分析和定量比较。研究表明,采用FLAASH模块对Worldview3数据进行大气校正方法切实可行、有效,典型地物——盐碱地、闪长岩的实测波谱和大气校正后获得反射波谱吻合程度较高,相关系数最高达到0.80。

With the development of remote sensing technology,the remote sensing has been developed from qualitative application to quantitative application,and atmospheric correction is an important part of quantitative remote sensing research.In this study,the authors used the FLAASH model of ENVI software to conduct atmospheric correction for Worldview3,a satellite image with high spatial resolution and high spectral resolution,and then evaluated the method.Worldview3 data and ASD measurement spectral data of typical ground objects(saline-alkali land and diorite)in Lop Nur were obtained.Firstly,the DN value of Worldview3 was converted into radiation brightness and apparent reflectance,and the atmosphere correction of Worldview3 image was carried out by using FLAASH model.The radiation brightness,apparent reflectance and FLAASH atmospheric corrected reflectance of two typical ground objects(saline-alkali land and diorite)in the study area were comparatively studied,and the measured reflection spectra of saline-alkali and diorite by ASD were also compared after resampling to the response band of Worldview3 by Gaussian filtering function.The results show that it is effective to apply FLAASH model to atmospheric correction of Worldview3 data,and the two methods can obtain high coincidence degree of reflection spectrum,with the correlation coefficient reaching 0.8.