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Author Spur, M.; Houel, N.; Tourre, V.
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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ISSN 2194-9034 ISBN Medium
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Notes Approved no
Call Number GFZ @ kyba @ Serial 3105
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Author Kolláth, Z.; Száz, D.; Tong, K.P.; Kolláth, K.
Title The Colour of the Night Sky Type Journal Article
Year 2020 Publication Journal of Imaging Abbreviated Journal J. Imaging
Volume 6 Issue 9 Pages 90
Keywords Skyglow; Natural light; Instrumentation
Abstract The measurement of night sky quality has become an important task in night sky conservation. Modern measurement techniques involve mainly a calibrated digital camera or a spectroradiometer. However, panchromatic devices are still prevalent to this day, even in the absence of determining the spectral information of the night sky. In the case of multispectral measurements, colour information is currently presented in multiple ways. One of the most frequently used metrics is correlated colour temperature (CCT), which is not without its limitation for the purpose of describing especially the colour of natural night sky. Moreover, visually displaying the colour of the night sky in a quantitatively meaningful way has not attracted sufficient attention in the community of astronomy and light pollution research—most photographs of the night sky are post-processed in a way for aesthetic attractiveness rather than accurate representation of the night sky. The spectrum of the natural night sky varies in a wide range depending on solar activity and atmospheric properties. The most noticeable variation in the visible range is the variation of the atomic emission lines, primarily the green oxygen and orange sodium emission. Based on the accepted models of night sky emission, we created a random spectral database which represents the possible range of night sky radiance distribution. We used this spectral database as a learning set, to create a colour transformation between different colour spaces. The spectral sensitivity of some digital cameras is also used to determine an optimal transformation matrix from camera defined coordinates to real colours. The theoretical predictions were extended with actual spectral measurements in order to test the models and check the local constituents of night sky radiance. Here, we present an extended modelling of night sky colour and recommendations of its consistent measurement, as well as methods of visualising the colour of night sky in a consistent way, namely using the false colour enhancement.
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ISSN 2313-433X ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 3120
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Author Strutt, R.J.
Title A photoelectric method of measuring the light of the night sky with studies of the course of variation through the night Type Journal Article
Year 1929 Publication Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character Abbreviated Journal Proc. R. Soc. Lond. A
Volume 124 Issue 794 Pages 395-408
Keywords Instrumentation; Natural Sky Brightness; Airglow
Abstract The investigations already published on the intensity of the night sky have been made by means of visual photometry, using a convenient instrument with a self-contained luminous source of radioactive origin. Nothing could rival this for simplicity and portability; it is always ready and requires no attention. On the other hand visual photometry is not a very satisfactory process even for ordinary light, and with this faint light it is far from giving the desirable degree of accuracy. I have therefore spent much effort in trying to replace it by some photoelectric method of measurement. A satisfactory method has now been evolved, and will be described, together with the results. A preliminary notice of the earlier results was given in a paper written at the request of Prof. S. Chapman, F. R. S., Chairman of the International Committee on Terrestrial and Solar Relationships, the receipt of which was acknowledged by him on June 19, 1928. The relevant passage is:- “Most of the difficulties have been overcome and preliminary observations have been in progress for some months past. I have been able to follow the changes of intensity from hour to hour on clear nights. Some evidence has been found suggesting diurnal periodicity. The observed intensity nearly always increases between nightfall and midnight, beyond which the observations have not usually been carried.”
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0950-1207 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 3124
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Author Wahl, F.; Kantermann, T.; Amft, O.
Title How much Light do you get? Estimating Daily Light Exposure using Smartphones Type Conference Article
Year 2014 Publication Proceedings of the 2014 ACM International Symposium on Wearable Computers Abbreviated Journal Proc. of the 2014 ACM International Symposium on Wearable Computers
Volume n/a Issue n/a Pages 43-46
Keywords Instrumentation; light exposure; context inference, light intensity; light intake; circadian clock; circadian rhythm; mobile sensing
Abstract We present an approach to estimate a persons light exposure using smartphones. We used web-sourced weather reports combined with smartphone light sensor data, time of day, and indoor/outdoor information, to estimate illuminance around the user throughout a day. Since light dominates every human’s circadian rhythm and influences the sleep-wake cycle, we developed a smartphone-based system that does not re- quire additional sensors for illuminance estimation. To evaluate our approach, we conducted a free-living study with 12 users, each carrying a smartphone, a head-mounted light reference sensor, and a wrist-worn light sensing device for six consecutive days. Estimated light values were compared to the head-mounted reference, the wrist-worn device and a mean value estimate. Our results show that illuminance could be estimated at less than 20% error for all study participants, outperforming the wrist-worn device. In 9 out of 12 participants the estimation deviated less than 10% from the reference measurements.
Address ACTLab, Chair of Sensor Technology, University of Passau (florian.wahl@uni-passau.de)
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Publisher (up) ACM Place of Publication Editor
Language English Summary Language English Original Title
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Notes Approved no
Call Number IDA @ john @ Serial 1206
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Author Kolláth, Z.; Cool, A.; Jechow, A.; Kolláth, K.; Száz, D.; Tong, K.P.
Title Introducing the Dark Sky Unit for multi-spectral measurement of the night sky quality with commercial digital cameras Type Journal Article
Year 2020 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer
Volume 253 Issue Pages 107162
Keywords Skyglow; Instrumentation; Measurement; light pollution; Radiometry
Abstract Multi-spectral imaging radiometry of the night sky provides essential information on light pollution (skyglow) and sky quality. However, due to the different spectral sensitivity of the devices used for light pollution measurement, the comparison of different surveys is not always trivial. In addition to the differences between measurement approaches, there is a strong variation in natural sky radiance due to the changes of airglow. Thus, especially at dark locations, the classical measurement methods (such as Sky Quality Meters) fail to provide consistent results. In this paper, we show how to make better use of the multi-spectral capabilities of commercial digital cameras and show their application for airglow analysis. We further recommend a novel sky quality metric the ”Dark Sky Unit”, based on an easily usable and SI traceable unit. This unit is a natural choice for consistent, digital camera-based measurements. We also present our camera system calibration methodology for use with the introduced metrics.
Address ELTE BDPK, Szombathely, Department of Physics, Hungary; zkollath(at)gmail.com
Corporate Author Thesis
Publisher (up) Elsever Place of Publication Elsevier Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4073 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 2998
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