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Author |
Fiorentin, P.; Boscaro, F. |
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Title |
A method for measuring the light output of video advertising reproduced by LED billboards |
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Journal Article |
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Year |
2019 |
Publication |
Measurement |
Abbreviated Journal |
Measurement |
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Volume |
138 |
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Pages |
25-33 |
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Keywords |
Lighting; Energy; Instrumentation; Planning; Light-emitting diode displays; Photometry; Video recording; Image analysis; CCD image sensors; Luminance; Glare |
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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. |
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Department of Industrial Engineering, University of Padova, Padova, Italy; pietro.fiorentin(at)unipd.it |
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Elsevier |
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English |
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English |
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0263-2241 |
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GFZ @ kyba @ |
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2214 |
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Author |
David, A.; Smet, K.A.G.; Whitehead, L. |
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Title |
Methods for Assessing Quantity and Quality of Illumination |
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Journal Article |
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Year |
2019 |
Publication |
Annual Review of Vision Science |
Abbreviated Journal |
Annu Rev Vis Sci |
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5 |
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Pages |
479-502 |
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Keywords |
Vision; Review; Photometry; Colorimetry |
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Abstract |
Human vision provides useful information about the shape and color of the objects around us. It works well in many, but not all, lighting conditions. Since the advent of human-made light sources, it has been important to understand how illumination affects vision quality, but this has been surprisingly difficult. The widespread introduction of solid-state light emitters has increased the urgency of this problem. Experts still debate how lighting can best enable high-quality vision-a key issue since about one-fifth of global electrical power production is used to make light. Photometry, the measurement of the visual quantity of light, is well established, yet significant uncertainties remain. Colorimetry, the measurement of color, has achieved good reproducibility, but researchers still struggle to understand how illumination can best enable high-quality color vision. Fortunately, in recent years, considerable progress has been made. Here, we summarize the current understanding and discuss key areas for future study. |
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Department of Physics and Astronomy, University of British Columbia, Vancouver BC V6T 1Z1, Canada; email: lorne.whitehead@ubc.ca |
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2374-4642 |
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PMID:31226013 |
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Call Number |
GFZ @ kyba @ |
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2576 |
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Author |
Schnitt, S.; Ruhtz, T.; Fischer, J.; Hölker, F.; Kyba, C.C.M. |
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Title |
Temperature stability of the sky quality meter |
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Journal Article |
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Year |
2013 |
Publication |
Sensors (Basel, Switzerland) |
Abbreviated Journal |
Sensors (Basel) |
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13 |
Issue |
9 |
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12166-12174 |
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Keywords |
*Artifacts; Atmosphere/*analysis; Environmental Monitoring/*instrumentation; Equipment Design; Equipment Failure Analysis; Photometry/*instrumentation; Reproducibility of Results; Sensitivity and Specificity; Temperature; *Transducers; Sky Quality Meter; SQM |
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Abstract |
The stability of radiance measurements taken by the Sky Quality Meter (SQM)was tested under rapidly changing temperature conditions during exposure to a stable light field in the laboratory. The reported radiance was found to be negatively correlated with temperature, but remained within 7% of the initial reported radiance over a temperature range of -15 degrees C to 35 degrees C, and during temperature changes of -33 degrees C/h and +70 degrees C/h.This is smaller than the manufacturer's quoted unit-to-unit systematic uncertainty of 10%,indicating that the temperature compensation of the SQM is adequate under expected outdoor operating conditions. |
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Institute for Space Sciences, Freie Universitat Berlin, Carl-Heinrich-Becker-Weg 6-10, Berlin 12165, Germany. christopher.kyba@wew.fu-berlin.de |
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1424-8220 |
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PMID:24030682; PMCID:PMC3821345 |
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Call Number |
IDA @ john @ |
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194 |
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Author |
Rybnikova, N.A.; Portnov, B.A. |
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Title |
Using light-at-night (LAN) satellite data for identifying clusters of economic activities in Europe |
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Journal Article |
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Year |
2015 |
Publication |
Letters in Spatial and Resource Sciences |
Abbreviated Journal |
Lett. Spatial & Resource Sci. |
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Volume |
8 |
Issue |
3 |
Pages |
307–334 |
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Keywords |
Remote Sensing; Economic activities; Clusters; Satellite photometry; Light-at-night; Europe; Nomenclature of Territorial Units for Statistics; C13; C38; O52; Economics |
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Abstract |
Enterprises organized in clusters are often efficient in stimulating urban development, productivity and profit outflows. Identifying the clusters of economic activities thus becomes an important step in devising regional development policies, aimed at the formation of clusters of economic activities in geographic areas in which this objective is desirable. However, a major problem with the identification of such clusters stems from limited reporting by individual countries and administrative entities on the regional distribution of specific economic activities, especially for small regional subdivisions. In this study, we test a possibility that missing data on geographic concentrations of economic activities in the European NUTS3 regions can be reconstructed using light-at-night satellite measurements, and that such reconstructed data can then be used for cluster identification. The matter is that light-at-night, captured by satellite sensors, is characterized by different intensity, depending on its source—production facilities, services, etc. As a result, light-at-night can become a marker of different types of economic activities, a hypothesis that the present study confirms. In particular, as the present analysis indicates, average light-at-night intensities emitted from NUTS3 regions help to explain up to 94 % variance in the areal density of several types of economic activities, performing especially well for professional, scientific and technical services (R^2=0.742−0.939), public administration (R^2=0.642−0.934), as well as for arts, entertainment and recreation (R^2=0.718−0.934). As a result, clusters of these economic activities can be identified using light-at-night data, thus helping to supplement missing information and assist regional analysis. |
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Department of Natural Resources and Environmental Management, Faculty of Management, University of Haifa, 31805, Mt. Carmel, Israel; Portnov@research.haifa.ac.il |
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Springer |
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English |
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English |
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IDA @ john @ |
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1148 |
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Author |
Bará, S. |
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Title |
Variations on a classical theme: On the formal relationship between magnitudes per square arcsecond and luminance |
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Journal Article |
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Year |
2017 |
Publication |
International Journal of Sustainable Lighting |
Abbreviated Journal |
Intl J of Sustainable Lighting |
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Volume |
19 |
Issue |
2 |
Pages |
77 |
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Keywords |
Instrumentation; skyglow; luminance; magnitude; sky brigthness; photometry |
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Abstract |
The formal link between magnitudes per square arcsecond and luminance is discussed in this paper. Directly related to the human visual system, luminance is defined in terms of the spectral radiance of the source, weighted by the CIE V(l) luminous efficiency function, and scaled by the 683 lm/W luminous efficacy constant. In consequence, any exact and spectrum-independent relationship between luminance and magnitudes per square arcsecond requires that the last ones be measured precisely in the CIE V(l) band. The luminance value corresponding to mVC=0 (zero-point of the CIE V(l) magnitude scale) depends on the reference source chosen for the definition of the magnitude system. Using absolute AB magnitudes, the zero point luminance of the CIE V(l) photometric band is 10.96 x 104 cd·m-2. |
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Departamento de Física Aplicada, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain; salva.bara(at)usc.es |
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English |
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English |
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2586-1247 |
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Call Number |
IDA @ john @ |
Serial |
2162 |
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