|
|
Fiorentin, P., & Boscaro, F. (2019). A method for measuring the light output of video advertising reproduced by LED billboards. Measurement, 138, 25–33.
Abstract: Improving knowledge of the light output of digital billboards is important to better assess their effect on driver distraction when they are installed along roads. In this work the emission of an LED based billboard is measured when playing advertising video-clips. In particular the average and the maximum values of the luminance are evaluated. The same video-clips are also analyzed when shown on an LCD monitor, aiming at separating the variability of the videos and of the playing device. The results allow to evaluate an utilization factor of the billboard: the videos have an average luminance around 11% and a peak luminance of 35% of the maximum luminance obtainable from the billboard. The power consumption of the billboard is measured, aside the photometric analysis. The luminance of the device are found linearly dependent on both the power and the effective current absorbed by the device from the grid, with a discrepancy within 6%. It could be a useful information for billboard manufacturers to qualify their product when they do not own photometric instruments.
|
|
|
|
Cinzano, P., & Falchi, F. (2003). A portable wide-field instrument for mapping night sky brightness automatically. Mem. S.A. It., 74(2), 458–459.
Abstract: We present a portable automatic instrument for monitoring night sky brightness and atmospherical transparency in astronomical photometrical bands. Main requirements were: fast and automatic coverage of the entire sky, lightness, transportability and quick set-up in order to take measurements from more sites in the same night, easily available commercial components and software to be reproduced by any interested institution, included amateurs astronomers groups.
|
|
|
|
Kyba, C. C. M., Ruhtz, T., Fischer, J., & Hölker, F. (2012). Red is the new black: how the colour of urban skyglow varies with cloud cover. Monthly Notices of the Royal Astronomical Society, 425(1), 701–708.
Abstract: The development of street lamps based on solid-state lighting technology is likely to introduce a major change in the colour of urban skyglow (one form of light pollution). We demonstrate the need for long-term monitoring of this trend by reviewing the influences it is likely to have on disparate fields. We describe a prototype detector which is able to monitor these changes, and could be produced at a cost low enough to allow extremely widespread use. Using the detector, we observed the differences in skyglow radiance in red, green and blue channels. We find that clouds increase the radiance of red light by a factor of 17.6, which is much larger than that for blue (7.1). We also find that the gradual decrease in sky radiance observed on clear nights in Berlin appears to be most pronounced at longer wavelengths.
|
|
|
|
Bará, S. (2017). Characterizing the zenithal night sky brightness in large territories: how many samples per square kilometre are needed? Monthly Notices of the Royal Astronomical Society, 473(3), 4164–4173.
Abstract: A recurring question arises when trying to characterize, by means of measurements or theoretical calculations, the zenithal night sky brightness throughout a large territory: how many samples per square kilometre are needed? The optimum sampling distance should allow reconstructing, with sufficient accuracy, the continuous zenithal brightness map across the whole region, whilst at the same time avoiding unnecessary and redundant oversampling. This paper attempts to provide some tentative answers to this issue, using two complementary tools: the luminance structure function and the Nyquist–Shannon spatial sampling theorem. The analysis of several regions of the world, based on the data from the New world atlas of artificial night sky brightness, suggests that, as a rule of thumb, about one measurement per square kilometre could be sufficient for determining the zenithal night sky brightness of artificial origin at any point in a region to within ±0.1 magV arcsec–2 (in the root-mean-square sense) of its true value in the Johnson–Cousins V band. The exact reconstruction of the zenithal night sky brightness maps from samples taken at the Nyquist rate seems to be considerably more demanding.
|
|
|
|
Gaston, K. J. (2013). Sustainability: A green light for efficiency. Nature, 497(7451), 560–561.
|
|
