de Meester Jasper, Storch Tobias
German Aerospace Center (DLR), Earth Observation Center (EOC), Münchener Str. 20, 82234 Weßling, Germany.
Sensors (Basel). 2020 Jun 10;20(11):3313. doi: 10.3390/s20113313.
Contrary to its daytime counterpart, nighttime visible and near infrared (VIS/NIR) satellite imagery is limited in both spectral and spatial resolution. Nevertheless, the relevance of such systems is unquestioned with applications to, e.g., examine urban areas, derive light pollution, and estimate energy consumption. To determine optimal spectral bands together with required radiometric and spatial resolution, at-sensor radiances are simulated based on combinations of lamp spectra with typical luminances according to lighting standards, surface reflectances, and radiative transfers for the consideration of atmospheric effects. Various band combinations are evaluated for their ability to differentiate between lighting types and to estimate the important lighting parameters: efficacy to produce visible light, percentage of emissions attributable to the blue part of the spectrum, and assessment of the perceived color of radiation sources. The selected bands are located in the green, blue, yellow-orange, near infrared, and red parts of the spectrum and include one panchromatic band. However, these nighttime bands tailored to artificial light emissions differ significantly from the typical daytime bands focusing on surface reflectances. Compared to existing or proposed nighttime or daytime satellites, the recommended characteristics improve, e.g., classification of lighting types by >10%. The simulations illustrate the feasible improvements in nocturnal VIS/NIR remote sensing which will lead to advanced applications.
与白天的情况相反,夜间可见光和近红外(VIS/NIR)卫星图像在光谱和空间分辨率方面都受到限制。然而,此类系统在诸如检查城市区域、推导光污染以及估计能源消耗等应用中的相关性是毋庸置疑的。为了确定最佳光谱波段以及所需的辐射分辨率和空间分辨率,根据照明标准、表面反射率以及考虑大气效应的辐射传输,基于灯谱与典型亮度的组合来模拟传感器处的辐亮度。评估各种波段组合区分照明类型以及估计重要照明参数的能力:产生可见光的效能、光谱蓝色部分的排放百分比以及对辐射源感知颜色的评估。所选波段位于光谱的绿色、蓝色、黄橙色、近红外和红色部分,并且包括一个全色波段。然而,这些针对人造光排放量身定制的夜间波段与专注于表面反射率的典型白天波段有显著差异。与现有的或提议的夜间或白天卫星相比,推荐的特性例如照明类型的分类提高了10%以上。这些模拟说明了夜间VIS/NIR遥感的可行改进,这将带来先进的应用。