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Author Yuan, X.; Jia, L.; Menenti, M.; Zhou, J.; Chen, Q. url  doi
openurl 
  Title Filtering the NPP-VIIRS Nighttime Light Data for Improved Detection of Settlements in Africa Type Journal Article
  Year 2019 Publication Remote Sensing Abbreviated Journal Remote Sensing  
  Volume 11 Issue 24 Pages 3002  
  Keywords Remote Sensing; Instrumentation  
  Abstract Observing and understanding changes in Africa is a hotspot in global ecological environmental research since the early 1970s. As possible causes of environmental degradation, frequent droughts and human activities attracted wide attention. Remote sensing of nighttime light provides an effective way to map human activities and assess their intensity. To identify settlements more effectively, this study focused on nighttime light in the northern Equatorial Africa and Sahel settlements to propose a new method, namely, the patches filtering method (PFM) to identify nighttime lights related to settlements from the National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite (NPP-VIIRS) monthly nighttime light data by separating signal components induced by biomass burning, thereby generating a new annual image in 2016. The results show that PFM is useful for improving the quality of NPP-VIIRS monthly nighttime light data. Settlement lights were effectively separated from biomass burning lights, in addition to capturing the seasonality of biomass burning. We show that the new 2016 nighttime light image can very effectively identify even small settlements, notwithstanding their fragmentation and unstable power supply. We compared the image with earlier NPP-VIIRS annual nighttime light data from the National Oceanic and Atmospheric Administration (NOAA) National Center for Environmental Information (NCEI) for 2016 and the Sentinel-2 prototype Land Cover 20 m 2016 map of Africa released by the European Space Agency (ESA-S2-AFRICA-LC20). We found that the new annual nighttime light data performed best among the three datasets in capturing settlements, with a high recognition rate of 61.8%, and absolute superiority for settlements of 2.5 square kilometers or less. This shows that the method separates biomass burning signals very effectively, while retaining the relatively stable, although dim, lights of small settlements. The new 2016 annual image demonstrates good performance in identifying human settlements in sparsely populated areas toward a better understanding of human activities.  
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  ISSN 2072-4292 ISBN Medium  
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  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2890  
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Author Coesfeld, J.; Kuester, T.; Kuechly, H.U.; Kyba, C.C.M. url  doi
openurl 
  Title Reducing Variability and Removing Natural Light from Nighttime Satellite Imagery: A Case Study Using the VIIRS DNB Type Journal Article
  Year 2020 Publication Sensors Abbreviated Journal Sensors  
  Volume 20 Issue 11 Pages 3287  
  Keywords Remote Sensing; Instrumentation  
  Abstract Temporal variation of natural light sources such as airglow limits the ability of night light sensors to detect changes in small sources of artificial light (such as villages). This study presents a method for correcting for this effect globally, using the satellite radiance detected from regions without artificial light emissions. We developed a routine to define an approximate grid of locations worldwide that do not have regular light emission. We apply this method with a 5 degree equally spaced global grid (total of 2016 individual locations), using data from the Visible Infrared Imaging Radiometer Suite (VIIRS) Day-Night Band (DNB). This code could easily be adapted for other future global sensors. The correction reduces the standard deviation of data in the Earth Observation Group monthly DNB composites by almost a factor of two. The code and datasets presented here are available under an open license by GFZ Data Services, and are implemented in the Radiance Light Trends web application.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1424-8220 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2988  
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Author Bará, S.; Tapia, C.; Zamorano, J. url  doi
openurl 
  Title Absolute Radiometric Calibration of TESS-W and SQM Night Sky Brightness Sensors Type Journal Article
  Year 2019 Publication Sensors Abbreviated Journal Sensors  
  Volume 19 Issue 6 Pages 1336  
  Keywords Instrumentation; calibration; SQM; TESS; photometer; sky brightness  
  Abstract We develop a general optical model and describe the absolute radiometric calibration of the readings provided by two widely-used night sky brightness sensors based on irradiance-to-frequency conversion. The calibration involves the precise determination of the overall spectral sensitivity of the devices and also the constant G relating the output frequency of the light-to-frequency converter chip to the actual band-weighted and field-of-view averaged spectral radiance incident on the detector (brightness). From these parameters, we show how to define a rigorous astronomical absolute photometric system in which the sensor measurements can be reported in units of magnitudes per square arcsecond with precise physical meaning.  
  Address Departmento Física Aplicada, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain; salva.bara(at)usc.es  
  Corporate Author Thesis  
  Publisher MDPI Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1424-8220 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 2263  
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Author Joachim, L.; Storch, T. url  doi
openurl 
  Title Cloud Detection For Night-Time Panchromatic Visible And Near-Infrared Satellite Imagery Type Journal Article
  Year 2020 Publication ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences Abbreviated Journal ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci.  
  Volume V-2-2020 Issue Pages 853-860  
  Keywords Instrumentation; Remote Sensing  
  Abstract Cloud detection for night-time panchromatic visible and near-infrared (VNIR) satellite imagery is typically performed based on synchronized observations in the thermal infrared (TIR). To be independent of TIR and to improve existing algorithms, we realize and analyze cloud detection based on VNIR only, here NPP/VIIRS/DNB observations. Using Random Forest for classifying cloud vs. clear and focusing on urban areas, we illustrate the importance of features describing a) the scattering by clouds especially over urban areas with their inhomogeneous light emissions and b) the normalized differences between Earth’s surface and cloud albedo especially in presence of Moon illumination. The analyses substantiate the influences of a) the training site and scene selections and b) the consideration of single scene or multi-temporal scene features on the results for the test sites. As test sites, diverse urban areas and the challenging land covers ocean, desert, and snow are considered. Accuracies of up to 85% are achieved for urban test sites.  
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  ISSN 2194-9050 ISBN Medium  
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  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 3064  
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Author Spur, M.; Houel, N.; Tourre, V. url  doi
openurl 
  Title Visualizing Multilayered Geospatial Data In Virtual Reality To Assess Public Lighting Type Journal Article
  Year 2020 Publication ISPRS – International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences Abbreviated Journal Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.  
  Volume Xliii-B4-2020 Issue Pages 623-630  
  Keywords Lighting; Instrumentation; Vision  
  Abstract With the improvement and proliferation of virtual reality devices, their use for research and professional activity is broadening,fostering the advent of the field of immersive analytics, as is their acceptance among consumers. Other than the heightened sense of immersion into visualized data they provide, they also make displays of much larger apparent size and different positioning practical than what would be possible otherwise. Drawing on these benefits, we implemented a development of Multiple and Coordinated Displays (MCVs) for geovisualization that stacks different layers of data above each other, tilted for legibility. In a formal experiment, we evaluated it and two other, comparable MCV methods implemented in VR for their usefulness in analyzing public perception and soliciting public feedback regarding urban street lighting. In that field, the direction has recently been shifting from purely systemic development to a participatory approach, thus our investigation was into how a system like this could facilitate participation that can yield actionable results. Previous analysis of interaction data and usability questionnaires reveals preferences for certain systems depending on user characteristics, with the stack system showing a slight advantage over a grid of layers and especially over temporal multiplexing. We show that regardless of MCV variation, participants were able to analyze and provide feedback on public lighting situations that can directly contribute to urbanist work. The MCV approach further aided in understanding their choices, as eye-tracking allowed us to analyze attention to individual data layers.  
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  Series Volume Series Issue Edition  
  ISSN 2194-9034 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 3105  
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