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Author (up) Bouroussis, C.A.; Topalis, F.V.
Title The effect of the spectral response of measurement instruments in the assessment of night sky brightness Type Journal Article
Year 2018 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer
Volume 216 Issue Pages 56-69
Keywords Skyglow; Instrumentation
Abstract This paper deals with the errors and uncertainties in skyglow measurements caused by the variation of sky's spectrum. It considers the theoretical spectral response of common instruments that are used for light pollution assessment. Various types of light sources were used in this investigation. This study calculates the spectral mismatch errors and the corresponding correction factors for each combination of instrument and light source. The calculation method is described and the results are presented in multiple figures. Calculated data show a big variation in potential errors that can be introduced when comparing readings of diverse instruments without considering the sky spectrum variation. This makes the spectral data of the sky a mandatory input to the dark sky assessment. Useful conclusions, related to instruments with better or worse behaviour, are derived from the calculations. The paper also includes suggestions on how to conduct multi-instrument measurements with or without spectral data.
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Series Volume Series Issue Edition
ISSN 0022-4073 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 1908
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Author (up) Burggraaff, O., Schmidt, N., Zamorano, J., Pauly, K., Pascual, S., Tapia, C., Spyrakos, E., & Snik, F.
Title Standardized spectral and radiometric calibration of consumer cameras Type Journal Article
Year 2019 Publication Optical Express Abbreviated Journal
Volume 27 Issue 14 Pages 19075-19101
Keywords Instrumentation
Abstract Consumer cameras, particularly onboard smartphones and UAVs, are now commonly used as scientific instruments. However, their data processing pipelines are not optimized for quantitative radiometry and their calibration is more complex than that of scientific cameras. The lack of a standardized calibration methodology limits the interoperability between devices and, in the ever-changing market, ultimately the lifespan of projects using them. We present a standardized methodology and database (SPECTACLE) for spectral and radiometric calibrations of consumer cameras, including linearity, bias variations, read-out noise, dark current, ISO speed and gain, flat-field, and RGB spectral response. This includes golden standard ground-truth methods and do-it-yourself methods suitable for non-experts. Applying this methodology to seven popular cameras, we found high linearity in RAW but not JPEG data, inter-pixel gain variations >400% correlated with large-scale bias and read-out noise patterns, non-trivial ISO speed normalization functions, flat-field correction factors varying by up to 2.79 over the field of view, and both similarities and differences in spectral response. Moreover, these results differed wildly between camera models, highlighting the importance of standardization and a centralized database.
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Notes Approved no
Call Number IDA @ intern @ Serial 2652
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Author (up) Chen, H.; Xiong, X.; Geng, X.; Twedt, K.
Title Stray-light correction and prediction for Suomi National Polar-orbiting Partnership visible infrared imaging radiometer suite day-night band Type Journal Article
Year 2019 Publication Journal of Applied Remote Sensing Abbreviated Journal J. Appl. Rem. Sens.
Volume 13 Issue 02 Pages 1
Keywords Instrumentation; Remote Sensing
Abstract The Suomi National Polar-orbiting Partnership visible infrared imaging radiometer suite instrument has successfully operated since its launch in October 2011. Stray-light contamination is much larger than prelaunch expectations, and it causes a major decrease in quality of the day-night band night imagery when the spacecraft is crossing the Northern or Southern day-night terminators. The stray light can be operationally estimated using Earth-view data that are measured over dark surfaces during the new moon each month. More than 7 years of nighttime images have demonstrated that the stray-light contamination mainly depends on the Earth–Sun–spacecraft geometry, so its intensity is generally estimated as a function of the satellite zenith angle. In practice, stray-light contamination is also detector- and scan-angle-dependent. Previous methods of stray-light prediction generally rely on using the known stray light level from the same month in the previous year, when the Earth–Sun–spacecraft geometries had been similar. We propose a new method to predict stray-light contamination. The Kullback–Leibler similarity metric is used as a method to combine data from multiple years with appropriate adjustments for degradation and geometry drifts in order to calculate a fused stray-light contamination correction. The new method provides an improved prediction of stray-light contamination compared to the existing methods and may be considered for future use in the real-time NASA Level-1B products.
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ISSN 1931-3195 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2517
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Author (up) Choi, T.; Shao, X.; Cao, C.; Weng, F.
Title Radiometric Stability Monitoring of the Suomi NPP Visible Infrared Imaging Radiometer Suite (VIIRS) Reflective Solar Bands Using the Moon Type Journal Article
Year 2016 Publication Remote Sensing Abbreviated Journal Remote Sensing
Volume 8 Issue 1 Pages 15
Keywords Instrumentation
Abstract The Suomi NPP (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) performs the scheduled lunar roll maneuver on a monthly basis. The lunar calibration coefficients and lunar F-factor are calculated by taking the ratio of the lunar observed radiance to the simulated radiance from the Miller and Turner (MT) lunar model. The lunar F-factor is also validated against that derived from the VIIRS Solar Diffuser (SD). The MT model-based lunar F-factors in general agree with SD F-factors. The Lunar Band Ratio (LBR) is also derived from two channel lunar radiances and is implemented in the National Oceanic and Atmospheric Administration (NOAA) Integrated Calibration and Validation System (ICVS) to monitor the VIIRS long-term radiometric performance. The lunar radiances at pixels are summed for each of the VIIRS Reflective Solar Bands (RSBs) and normalized by the reference band M11 which has the most stable SD-based calibration coefficient. LBRs agree with the SD based F-factor ratios within one percent. Based on analysis with these two independent lunar calibration methods, SD-based and LBR-based calibrations show a lifetime consistency. Thus, it is recommended that LBR be used for both VIIRS radiometric calibration and lifetime stability monitoring.
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ISSN 2072-4292 ISBN Medium
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Notes Approved no
Call Number LoNNe @ kyba @ Serial 1384
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Author (up) Cinzano, P.
Title Night Sky Photometry with Sky Quality Meter Type Journal Article
Year 2005 Publication Technical Report 9, ISTIL. V1.4. Abbreviated Journal
Volume Issue Pages
Keywords Instrumentation; light pollution; night sky brightness; photometry; instruments; calibration
Abstract Sky Quality Meter, a low cost and pocket size night sky brightness photometer, opens to the general public the possibility to quantify the quality of the night sky. Expecting a large diffusion of measurements taken with this instrument, I tested and characterized it. I analyzed with synthetic photometry and laboratory measurements the relationship between the SQM photometrical system and the main systems used in light pollution studies. I evaluated the conversion factors to Johnson’s B and V bands, CIE photopic and CIE scotopic responses for typical spectra and the spectral mismatch correction factors when specific filters are added.
Address Dipartimento di Astronomia, Vicolo dell’Osservatorio 2, I-35100 Padova, Italy; cinzano(at)lplab.it
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Publisher ISTIL Place of Publication Editor
Language English Summary Language English Original Title
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Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial 473
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