Wang, G., Wang, S., Zhang, L., Sun, F., Yan, F., & Yang, X. (2019). A New Light Control Method with Charge Induction of Moving Target. IEEE Sensors Journal, 19(16).
Abstract: Intelligent lamp control system has been widely studied all over the world because of its energy saving and social effect. In this paper, a new intelligent lamp control method based on charge induction for moving target is proposed. The detection model is established with the surface charge induction and verified by a luggage detection experiment. The intelligent lamp control system using the detection method is carried out. The performance of the system demonstrates that the proposed method can detect the moving target at any orientation whatever with or without occlusion and the detection distance can reach more than 3 m for the pedestrian.
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Wilson, T., & Xiong, X. (2020). Intercomparison of the SNPP and NOAA-20 VIIRS DNB High-Gain Stage Using Observations of Bright Stars. IEEE Transactions on Geoscience and Remote Sensing, , 1–8.
Abstract: The Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Suomi-NPP (SNPP) and NOAA-20 (N20) spacecrafts is a multispectral Earth-observing instrument with bands covering wavelengths from visible to long-wave infrared. Among these bands is a panchromatic day/night band (DNB) with a broad spectral response ranging from 500 to 900 nm, and a high dynamic range spanning over seven orders of magnitude, allowing for observations to take place during both daytime and nighttime. The DNB operates at three gain levels, with low- and mid-gain stages and two high-gain stages (HGSs). The HGS is capable of detecting dim city lights during Earth-view observations at night as well as bright stars through the instrument space-view port. Since SNPP and N20 are at opposite points of the same orbit, each VIIRS instrument is able to observe the same stars with the DNB in successive orbits. This will allow us to make a direct comparison of the relative calibration of each instrument using stars over a range of spectral classes. In this article, we develop methodology for accurately identifying target stars in order to make proper comparisons between the DNB HGS of each instrument. We then take observations from multiple stars in order to compute the ratio in the measured irradiance for each instrument as a function of spectral class. For K-type stars, which have the least spectral change over the DNB wavelength range, we measure a calibration bias between the SNPP and N20 DNB HGS of approximately 4%, which is stable over the duration of the N20 mission.
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Schwarting, T., McIntire, J., Oudrari, H., & Xiong, X. (2019). JPSS-1/NOAA-20 VIIRS Day-Night Band Prelaunch Radiometric Calibration and Performance. IEEE Transactions on Geoscience and Remote Sensing, , 1–13.
Abstract: The Visible Infrared Imaging Radiometer Suite (VIIRS) on board the first Joint Polar-Orbiting Satellite System series 1 (JPSS-1) has a panchromatic, three gain stage, day-night band (DNB) capable of imaging the Earth under illumination conditions ranging from reflected moonlight to daytime scenes. The DNB has four charged-coupled devices (CCDs) with 32 different modes of time-delay integration and subpixel aggregation to achieve high SNR in low light conditions while maintaining roughly constant spatial resolution across scan. During the prelaunch testing phase, these 32 different aggregation modes are separately calibrated over a large dynamic range (covering seven orders of magnitude) through a series of radiometric tests designed to generate initial calibration coefficients for the sensor data record (SDR) operational algorithm, assess radiometric performance, and determine compliance with the sensor design requirements. Early in the environmental testing at the Raytheon El Segundo facility, nonlinear behavior was discovered in some DNB edge of scan aggregation modes at low signal levels. In response to this nonlinearity, the test program was altered to characterize the radiometric performance both in the baseline configuration and with a modified aggregation scheme that eliminates the modes used at the end of scan, replacing them with an unaffected adjacent mode and trading off spatial resolution for improved linearity. Presented in this paper is the radiometric performance under both sensor configurations including dynamic range, sensitivity, radiometric uncertainty, and nonlinearity along with a discussion of the potential impact to DNB on-orbit calibration and SDR performance.
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Kocifaj, M., & Bará, S. (2020). Night-time monitoring of the aerosol content of the lower atmosphere by differential photometry of the anthropogenic skyglow. Monthly Notices of the Royal Astronomical Society: Letters, 500(1), L47–L51.
Abstract: Night-time monitoring of the aerosol content of the lower atmosphere is a challenging task, because appropriate reference natural light sources are lacking. Here, we show that the anthropogenic night-sky brightness due to city lights can be successfully used for estimating the aerosol optical depth of arbitrarily thick atmospheric layers. This method requires measuring the zenith night-sky brightness with two detectors located at the limiting layer altitudes. Combined with an estimate of the overall atmospheric optical depth (available from ground-based measurements or specific satellite products), the ratio of these radiances provides a direct estimate of the differential aerosol optical depth of the air column between these two altitudes. These measurements can be made with single-channel low-cost radiance detectors widely used by the light pollution research community.
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Masana, E., Carrasco, J. M., Bará, S., & Ribas, S. J. (2021). A multiband map of the natural night sky brightness including Gaia and Hipparcos integrated starlight. Monthly Notices of the Royal Astronomical Society, 501(4), 5443–5456.
Abstract: The natural night sky brightness is a relevant input for monitoring the light pollution evolution at observatory sites, by subtracting it from the overall sky brightness determined by direct measurements. It is also instrumental for assessing the expected darkness of the pristine night skies. The natural brightness of the night sky is determined by the sum of the spectral radiances coming from astrophysical sources, including zodiacal light, and the atmospheric airglow. The resulting radiance is modified by absorption and scattering before it reaches the observer. Therefore, the natural night sky brightness is a function of the location, time, and atmospheric conditions. We present in this work the GAia Map of the Brightness Of the Natural Sky (GAMBONS), a model to map the natural night brightness of the sky in cloudless and moonless nights. Unlike previous maps, GAMBONS is based on the extra-atmospheric star radiance obtained from the Gaia catalogue. The Gaia-Data Release 2 (DR2) archive compiles astrometric and photometric information for more than 1.6 billion stars up to G = 21 mag. For the brightest stars, not included in Gaia-DR2, we have used the Hipparcos catalogue instead. After adding up to the star radiance the contributions of the diffuse galactic and extragalactic light, zodiacal light and airglow, and taking into account the effects of atmospheric attenuation and scattering, the radiance detected by ground-based observers can be estimated. This methodology can be applied to any photometric band, if appropriate transformations from the Gaia bands are available. In particular, we present the expected sky brightness for V (Johnson), and visual photopic and scotopic passbands.
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