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Author Jung, B.; Inanici, M.
Title Measuring circadian lighting through high dynamic range photography Type Journal Article
Year 2018 Publication Lighting Research & Technology Abbreviated Journal (up) Lighting Research & Technology
Volume in press Issue Pages in press
Keywords Instrumentation; Human Health
Abstract The human ocular system functions in a dual manner. While the most well-known function is to facilitate vision, a growing body of research demonstrates its role in resetting the internal body clock to synchronize with the 24-hour daily cycle. Most research on circadian rhythms is performed in controlled laboratory environments. Little is known about the variability of circadian light within the built and natural environments. Currently, very few specialized devices measure the circadian light, and they are not accessible to many researchers and practitioners. In this paper, tristimulus colour calibration procedures for high dynamic range photography are developed to measure circadian lighting. Camera colour accuracy is evaluated through CIE trichromatic (XYZ) measurements; and the results demonstrate a strong linear relationship between the camera recordings and a scientific-grade colorimeter. Therefore, it is possible to correct for the colour aberrations and use high dynamic range photographs to measure both photopic and circadian lighting values. Spectrophotometric measurements are collected to validate the methodology. Results demonstrate that measurements from high dynamic range photographs can correspond to the physical quantity of circadian luminance with reasonable precision and repeatability. Circadian data collected in built environments can be utilized to study the impact of design decisions on human circadian entrainment and to create guidelines and metrics for designing circadian friendly environments.
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ISSN 1477-1535 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 1979
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Author Laurìa, A.; Secchi, S.; Vessella, L.
Title Visual wayfinding for partially sighted pedestrians – The use of luminance contrast in outdoor pavings Type Journal Article
Year 2018 Publication Lighting Research & Technology Abbreviated Journal (up) Lighting Research & Technology
Volume in press Issue Pages in press
Keywords Lighting
Abstract An increase in the number of partially sighted people is one of the effects of population ageing. These people have great difficulties in gathering wayfinding information to move independently in an unfamiliar environment. Guide paths based on the luminance contrast between a strip and surrounding surfaces can be an effective device for mitigating these difficulties, but information provided by the scientific literature on guide paths cannot be usefully applied to the naturally coloured paving materials most commonly found in pedestrian urban spaces. This paper presents a simplified method for measuring the luminance contrast between a guide strip and its background using combinations of naturally coloured paving materials.
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Series Volume Series Issue Edition
ISSN 1477-1535 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 1980
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Author Davidovic, M.; Djokic, L.; Cabarkapa, A.; Kostic, M.
Title Warm white versus neutral white LED street lighting: Pedestrians' impressions Type Journal Article
Year 2018 Publication Lighting Research & Technology Abbreviated Journal (up) Lighting Research & Technology
Volume in press Issue Pages 147715351880429
Keywords Psychology; Security
Abstract The subjective impressions of pedestrians are necessary in order to decide on the appropriate colour of light to be used for street lighting. Therefore, a pilot project aimed to compare subjective evaluations of the sidewalk illumination under two street lighting installations, realised by LEDs of 3000 K (warm white) and 4000 K (neutral white), was recently conducted in Belgrade. Both installations had comparable sidewalk illuminances as well as other relevant photometric parameters. The evaluation was done through a questionnaire. A group of 139 (61 male and 78 female) respondents, all of them university students, was asked to grade both lighting installations for the sidewalk light intensity, the appearance of human faces, the colour of light and the colour rendering as well as the overall impression. According to the median values, the 3000 K LED installation was considered better than the 4000 K installation for all aspects assessed as well as the overall impression. Although the survey results convincingly showed a preference for 3000 K LEDs for this comparison, additional research is needed using a more representative sample of people and a wider range of locations before a definite conclusion can be reached.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1477-1535 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2045
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Author Fotios, S.; Monteiro, A.L.; Uttley, J.
Title Evaluation of pedestrian reassurance gained by higher illuminances in residential streets using the day–dark approach Type Journal Article
Year 2018 Publication Lighting Research & Technology Abbreviated Journal (up) Lighting Research & Technology
Volume in press Issue Pages
Keywords Vision; Psychology; Security
Abstract A field study was conducted to investigate how changes in the illuminance affect pedestrian reassurance when walking after dark in an urban location. The field study was conducted in daytime and after dark in order to employ the day–dark approach to analysis of optimal lighting. The results suggest that minimum illuminance is a better predictor of reassurance than is mean illuminance. For a day–dark difference of 0.5 units on a 6-point response scale, the results suggest a minimum horizontal illuminance of approximately 2.0 lux.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1477-1535 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2159
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Author Huang, Z.; Liu, Q.; Westland, S.; Pointer, M.; Luo, M.R.; Xiao, K.
Title Light dominates colour preference when correlated colour temperature differs Type Journal Article
Year 2018 Publication Lighting Research & Technology Abbreviated Journal (up) Lighting Research & Technology
Volume 50 Issue 7 Pages 995-1012
Keywords Vision; Lighting
Abstract Colour preference for lighting is generally influenced by three kinds of contextual factors, the light, the object and the observer. In this study, a series of psychophysical experiments were conducted to investigate and compare the effect of certain factors on colour preference, including spectral power distribution of light, lighting application, observers’ personal colour preference, regional cultural difference and gender difference. LED lights with different correlated colour temperatures were used to illuminate a wide selection of objects. Participant response was quantified by a 7-point rating method or a 5-level ranking method. It was found that the preferred illumination for different objects exhibited a similar trend and that the influence of light was significantly stronger than that of other factors. Therefore, we conclude that the light itself (rather than, e.g. the objects that are viewed) is the most crucial factor for predicting which light, among several candidates with different correlated colour temperatures, an observer will prefer. In addition, some of the gamut-based colour quality metrics correlated well with the participants’ response, which corroborates the view that colour preference is strongly influenced by colour saturation. The familiarity of the object affects the ratings for each experiment while the colour of the objects also influences colour preference.
Address School of Printing and Packaging, Wuhan University, Luoyu Road 129, Wuhan, China; liuqiang(at)whu.edu.cn
Corporate Author Thesis
Publisher SAGE Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1477-1535 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 2256
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