Evaluation of nighttime imaging limits of visible near-infrared Earth observation platforms

摘要

A subset of the existing NASA and NOAA families of Earth observation imaging platforms currently on orbit (Landsat 7, Advanced Land Imager (ALI), and the Defense Meteorological Satellite Program Operational Line Scanner) have a primary mission of imaging the Earth's landforms during the daylight hours. All three systems are capable of nighttime imaging operations, however this capability of Landsat and ALI is not frequently utilized due to lack of utility in the resulting data products. Many researchers have published science results on focused problems such as volcanic eruptions, wildfires, and urban settlement mapping. In this work we present a first-principles based radiometric framework for quantifying the capability of such imaging platforms for detecting the presence of boats in open waters taking into consideration the interaction between the boat and water surfaces. The low-level radiometric modeling is performed using both the DIRSIG software tool and MODTRAN, in conjunction with freely available boat geometric models, incandescent lamp spectra, and a randomly rough sea surface geometry. The resulting performance metric represents the minimum wattage of one or more incandescent illuminants that might be detected above the system noise floor for a variety of imaging geometries.