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Author Skinner, N., & Bullough, J.
Title Influence of LED Spectral Characteristics on Glare Recovery Type Journal Article
Year 2019 Publication SAE Technical Paper 2019-01-0845 Abbreviated Journal
Volume Issue Pages
Keywords (down) Vision; Lighting; Public Safety
Abstract Headlight glare is a major concern of the driving public. In the past couple of years there have been concerns expressed about the use of light emitting diode (LED) lighting technologies and possible impacts LEDs may have on people, including circadian disruption, retinal hazards, and glare. Under typical use cases, vehicle headlight exposures are insufficient to cause circadian disruption or retinal damage, but can result in disability and discomfort glare, as well as glare recovery. In general, white LEDs used for illumination have greater short-wavelength content than halogen lamps used in many headlights, and short wavelengths have been implicated in visual discomfort from bright lights at night. Previous literature is inconsistent regarding whether the spectral (color) content of a glare source affects the amount of recovery time needed to see objects, following exposure to a bright light such as a vehicle headlight. Warm and cool white LEDs were used as glare sources in the present study. They were energized and exposed to study participants at one of two illuminances (low, high) for either 3 or 6 seconds, after which participants were asked to identify the orientation of a Landolt ring target located on a display screen behind the glare source. Identification times were unaffected by the spectral content of the LED, but were correlated with the “dosage” of light from the glare sources, defined as the product of illuminance and duration. Although cool white LEDs will tend to be judged as creating more discomfort than warm white LEDs, they do not result in longer glare recovery times under the range of conditions used in this study.
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Call Number IDA @ intern @ Serial 2299
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Author Ayuga, C.E.T.; Zamorano, J.
Title LICA AstroCalc, a software to analyze the impact of artificial light: Extracting parameters from the spectra of street and indoor lamps Type Journal Article
Year 2018 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer
Volume 214 Issue Pages 33-38
Keywords (down) Vision; Lighting; Instrumentation
Abstract The night sky spectra of light-polluted areas is the result of the artificial light scattered back from the atmosphere and the reemission of the light after reflections in painted surfaces. This emission comes mainly from street and decorative lamps. We have built an extensive database of lamps spectra covering from UV to near IR and the software needed to analyze them. We describe the LICA-AstroCalc free software that is a user friendly GUI tool to extract information from our database spectra or any other user provided spectrum. The software also includes the complete color database of paints from NCS comprising 1950 types. This helps to evaluate how different colors modify the reflected spectra from different lamps. All spectroscopic measurements have been validated with recommendations from CIELAB and ISO from NCS database.
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ISSN 0022-4073 ISBN Medium
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Notes Approved no
Call Number GFZ @ kyba @ Serial 1882
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Author Bullough, J.D.
Title Spectral sensitivity for extrafoveal discomfort glare Type Journal Article
Year 2009 Publication Journal of Modern Optics Abbreviated Journal Journal of Modern Optics
Volume 56 Issue 13 Pages 1518-1522
Keywords (down) Vision; Lighting
Abstract Previously published evidence suggests that the discomfort glare response to bright lights has greater short-wavelength spectral sensitivity than implied by the photopic luminous efficiency function, V(λ). The present paper summarizes a series of experiments to characterize spectral sensitivity for discomfort glare from nearly monochromatic light sources presented in the near extrafovea (5° and 10° off-axis). The results are consistent with increased participation in the discomfort glare response from short-wavelength cones and greater short-wavelength sensitivity as eccentricity increases. From the results an empirical family of luminous efficiency functions, V DG(λ), for discomfort glare, is derived. Such data could have implications for specifications of roadway lighting, vehicle headlamps or other light sources that might contribute to discomfort glare.
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ISSN 0950-0340 ISBN Medium
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Notes Approved no
Call Number LoNNe @ kyba @ Serial 1759
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Author S Fotios, J Uttley
Title Illuminance required to detect a pavement obstacle of critical size Type Journal Article
Year 2018 Publication Lighting Research & Technology Abbreviated Journal
Volume 50 Issue Pages 390-404
Keywords (down) Vision; Lighting
Abstract This paper investigates the illuminance needed to detect trip hazards for pedestrians walking after dark. In previous work, it was assumed that the critical obstacle height is 25 mm: further review of accident data and foot clearance data suggests instead that 10 mm is the critical height. Eye tracking records suggest a tendency for obstacles to be detected approximately 3.4 m ahead. Interpretation of obstacle detection data suggests horizontal photopic illuminances of up to 0.9 lux are required for peripheral detection of a 10 mm obstacle 3.4 m ahead, according to the scotopic/photopic ratio of the lighting and the age of the observer.
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Call Number LoNNe @ kyba @ Serial 1765
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Author Preciado, O.; Manzano, E.
Title Spectral characteristics of road surfaces and eye transmittance: Effects on energy efficiency of road lighting at mesopic levels Type Journal Article
Year 2017 Publication Lighting Research & Technology Abbreviated Journal Lighting Research & Technology
Volume Issue Pages 147715351771822
Keywords (down) Vision; Lighting
Abstract In 2010, the CIE published a recommended system for mesopic photometry based on visual performance. According to this system, scenes illuminated at mesopic levels with light sources of high S/P ratio, will produce better visual performance than those illuminated with light sources of a lower S/P ratio at equal photopic luminance. However, there could be other factors affected by SPD that, when quantified, could lead to a contradictory final effect. The scope of this paper was to evaluate how road lighting is affected by the spectral road surface reflectance and by the human eye transmittance as people get older. Our results suggest that the benefits of considering the mesopic vision effect for light sources with high S/P ratios are totally counteracted by the other two effects at mesopic luminances between 0.75 cd/m2 and 1.73 cd/m2 for people between 20 and 60 years of age, depending on the light source and the age of observers.
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ISSN 1477-1535 ISBN Medium
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Notes Approved no
Call Number GFZ @ kyba @ Serial 1862
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