Nighttime images taken with DSLR cameras from the International Space Station (ISS) can provide valuable information on the spatial and temporal variation of artificial nighttime lighting on Earth. In particular, this is the only source of historical and current visible multispectral data across the world (DMSP/OLS and SNPP/VIIRS-DNB data are panchromatic and multispectral in the infrared but not at visible wavelengths). The ISS images require substantial processing and proper calibration to exploit intensities and ratios from the RGB channels. Here we describe the different calibration steps, addressing in turn Decodification, Linearity correction (ISO dependent), Flat field/Vignetting, Spectral characterization of the channels, Astrometric calibration/georeferencing, Photometric calibration (stars)/Radiometric correction (settings correction - by exposure time, ISO, lens transmittance, etc) and Transmittance correction (window transmittance, atmospheric correction). We provide an example of the application of this processing method to an image of Spain.

使用国际空间站 (ISS) 的数码单反相机拍摄的夜间图像可以提供有关地球上人工夜间照明的空间和时间变化的宝贵信息。特别是，这是世界范围内历史和当前可见多光谱数据的唯一来源（DMSP/OLS 和 SNPP/VIIRS-DNB 数据是全色和多光谱红外数据，但不是可见光波长）。ISS 图像需要大量处理和适当的校准，以利用来自 RGB 通道的强度和比率。在这里，我们描述了不同的校准步骤，依次解决了解码、线性校正（取决于 ISO）、平场/渐晕、通道的光谱特性、天文校准/地理参考、光度校准（星星）/辐射校正（设置校正 - 通过曝光时间、ISO、镜头透光率等）和透光率校正（窗口透光率、大气校正）。我们提供了将此处理方法应用于西班牙图像的示例。