西沙群岛岛礁区域WorldView-2影像大气校正

Atmospheric correction of WorldView-2 data for the Xisha Islands and reefs imagery

高空间分辨率WorldView-2多波段影像方法在岛礁遥感监测方面应用潜力很大,但大气校正精度对其定量化应用有着重要影响。文章针对海洋遥感中WorldView-2影像大气校正的问题,改进传统的暗目标校正方法,以清、深海水和岛屿纯浓密植被作为暗目标,对西沙群岛岛礁区域进行应用示范,实现了各波段的大气校正。结果显示,该方法得到的结果无论从光谱形状还是地物反射率值,大气校正前后反射率值与现场实测值都能够较好吻合。

The high-resolution multi-band data of WorldView-2 has a great potential in monitoring islands and underwater reefs using remote sensing technology. The precision of atmospheric correction is an important and necessary procedure for quantitative application of such data. This study illustrates an effective atmospheric correction method of WorldView-2 images for marine applications, which is based on the traditional dark-object subtraction technique. Atmospheric correction was performed by selecting and extracting the deep clear water and dense vegetation of islands, respectively, as dark target pixels. Using the Xisha Islands and reefs as a study area, the WorldView-2 eight-band imagery was applied to calculate aerosol parameters, and the actual surface reflectance was obtained. In order to verify the results, we compared the retrieved reflectance with the original reflectance and field measurement data. The comparison shows that the computed reflectance was close to the situ measurement data in terms of both spectral shape and reflectance value.