Pub Date : 2023-09-20DOI: 10.1177/14771535231198564
J. Mardaljevic
This issue focuses on daylight-related research and a camera-based method to measure illuminance. Any form of illumination for occupied spaces – natural or artificial – needs to be considered in terms of both its quantity and its quality. A useful distinction, often made, is to consider quantity in terms of lux received on the task plane and quality in terms of the spectral power distribution of the light. While incomplete, it provided a useful starting point. Both the quantity and quality of illumination received at the eye are now a consideration for the assessment and/or prediction of the non-visual effects of light, for example, for circadian entrainment. The paper ‘Evaluation of sky spectra and sky models in daylighting simulations’ by Inanici et al. delves deeply into the various ways that the spectral component of illumination from sky light can be predicted. This timely study reveals much about the inner workings of these simulations and provides a much needed inter-model comparison. The prevailing qualitative character of illumination can also be inferred from measures of correlated colour temperature (CCT). While CCT has long been used to categorise sources of artificial light, the paper by Villalba et al. describes how to quantify the changes in CCT when direct solar radiation passes through various commonly used window shading materials. Titled ‘The impact of woven shade fabrics on correlated colour temperature and illuminance with daylighting’, the article presents empirical findings for a variety of shading materials. For a basement room where it is not possible have a window to the outside, the potential may exist to ‘collect’ daylight on the roof of the building and ‘transport’ it to the windowless space. One approach, which today has an established market presence, uses highly reflective light-pipes, typically 500 mm or greater in diameter. A promising rival approach uses instead a much thinner conduit made from a fibre-optic bundle, offering the potential for installation in buildings where space constraints may prohibit the use of the much larger light-pipes. Necessarily, the daylight collected on the roof must be concentrated for transport through the fibre-optic. The paper ‘Analysis, evaluation and integration of modular natural illumination system using a rectangular Fresnel lens for high performance’ by Garg et al. describes recent advances which could form the basis of a practical light-transport system based on fibre-optic bundles. Lastly, the paper ‘A joint validation study on camera-aided illuminance measurement’ by Mahlab et al. provides further evidence to support the use of camera-based methods to measure illuminance. As demonstrated in the article, using digital cameras to capture highdynamic range images of scenes has greatly expanded the potential for quantitative lighting analysis in realistic/complex scenes. This edition also offers a timely opportunity to remind potential contributors that the call for papers f
{"title":"Editorial: Daylight and illuminance measurement","authors":"J. Mardaljevic","doi":"10.1177/14771535231198564","DOIUrl":"https://doi.org/10.1177/14771535231198564","url":null,"abstract":"This issue focuses on daylight-related research and a camera-based method to measure illuminance. Any form of illumination for occupied spaces – natural or artificial – needs to be considered in terms of both its quantity and its quality. A useful distinction, often made, is to consider quantity in terms of lux received on the task plane and quality in terms of the spectral power distribution of the light. While incomplete, it provided a useful starting point. Both the quantity and quality of illumination received at the eye are now a consideration for the assessment and/or prediction of the non-visual effects of light, for example, for circadian entrainment. The paper ‘Evaluation of sky spectra and sky models in daylighting simulations’ by Inanici et al. delves deeply into the various ways that the spectral component of illumination from sky light can be predicted. This timely study reveals much about the inner workings of these simulations and provides a much needed inter-model comparison. The prevailing qualitative character of illumination can also be inferred from measures of correlated colour temperature (CCT). While CCT has long been used to categorise sources of artificial light, the paper by Villalba et al. describes how to quantify the changes in CCT when direct solar radiation passes through various commonly used window shading materials. Titled ‘The impact of woven shade fabrics on correlated colour temperature and illuminance with daylighting’, the article presents empirical findings for a variety of shading materials. For a basement room where it is not possible have a window to the outside, the potential may exist to ‘collect’ daylight on the roof of the building and ‘transport’ it to the windowless space. One approach, which today has an established market presence, uses highly reflective light-pipes, typically 500 mm or greater in diameter. A promising rival approach uses instead a much thinner conduit made from a fibre-optic bundle, offering the potential for installation in buildings where space constraints may prohibit the use of the much larger light-pipes. Necessarily, the daylight collected on the roof must be concentrated for transport through the fibre-optic. The paper ‘Analysis, evaluation and integration of modular natural illumination system using a rectangular Fresnel lens for high performance’ by Garg et al. describes recent advances which could form the basis of a practical light-transport system based on fibre-optic bundles. Lastly, the paper ‘A joint validation study on camera-aided illuminance measurement’ by Mahlab et al. provides further evidence to support the use of camera-based methods to measure illuminance. As demonstrated in the article, using digital cameras to capture highdynamic range images of scenes has greatly expanded the potential for quantitative lighting analysis in realistic/complex scenes. This edition also offers a timely opportunity to remind potential contributors that the call for papers f","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"16 1","pages":"501 - 501"},"PeriodicalIF":2.5,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139338426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-15DOI: 10.1177/14771535231194536
E Belloni, C Buratti, L Lunghi, L Martirano
Buildings, urban mobility and public lighting systems are promising areas for cities to reduce energy consumption. In this work, a smart city located in a central region of Italy was investigated and a new street lighting control algorithm was developed. The method is applied to manage the public lighting system of a real case study, where efficient technologies, such as LED lamps and control systems, are already installed. Preliminary on-site measurements of traffic and lighting parameters were carried out in specific streets chosen for the case studies. The analysis was supported with lighting simulations. Based on the results, a Python-based algorithm was developed to apply switching and dimming schedules to decrease the electricity consumption of the streets. A cost/benefit study was carried out and a preliminary analysis of the environmental impact of the proposed strategy is also included. The developed algorithm could be further improved based on other boundary conditions, such as daylighting and weather data.
{"title":"A new street lighting control algorithm based on forecasted traffic data for electricity consumption reduction","authors":"E Belloni, C Buratti, L Lunghi, L Martirano","doi":"10.1177/14771535231194536","DOIUrl":"https://doi.org/10.1177/14771535231194536","url":null,"abstract":"Buildings, urban mobility and public lighting systems are promising areas for cities to reduce energy consumption. In this work, a smart city located in a central region of Italy was investigated and a new street lighting control algorithm was developed. The method is applied to manage the public lighting system of a real case study, where efficient technologies, such as LED lamps and control systems, are already installed. Preliminary on-site measurements of traffic and lighting parameters were carried out in specific streets chosen for the case studies. The analysis was supported with lighting simulations. Based on the results, a Python-based algorithm was developed to apply switching and dimming schedules to decrease the electricity consumption of the streets. A cost/benefit study was carried out and a preliminary analysis of the environmental impact of the proposed strategy is also included. The developed algorithm could be further improved based on other boundary conditions, such as daylighting and weather data.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135396542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1177/14771535231175050
James Veitch, P. Blattner
{"title":"Editorial: Special issue on the CIE 2021 Midterm Meeting","authors":"James Veitch, P. Blattner","doi":"10.1177/14771535231175050","DOIUrl":"https://doi.org/10.1177/14771535231175050","url":null,"abstract":"","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"272 1","pages":"343 - 344"},"PeriodicalIF":2.5,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76559844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-20DOI: 10.1177/14771535231167999
Michael P. Royer
It’s been 100 years since Gibson and Tyndall formally proposed the values that were standardized a year later as the CIE spectral luminous efficiency function for photopic vision, V(λ). The 1920s was a decade when several new computing machines were introduced, but before the first introduction of modern electronic computers in the 1940s. Calculations involving the nascent lumen were likely done by hand and were then at the forefront of lighting science. By the 1960s, methods to calculate average horizontal illuminance, such as the zonal cavity method, were available and the subject of scientific research to understand error levels and extend applicability to new situations. With the increasing availability of personal computers in the 1980s and 1990s, new lighting software based on ray tracing models, radiosity models or a combination was introduced to ease the burden of computing lighting quantities, extend computational capabilities to a much wider range of applications and offer rendered images. The performance of lighting calculation software has continued to improve, and in the last several years, it has begun to include better modelling of spectral quantities as well. There’s still room to improve the speed, accuracy and utility of lighting calculations, and the five articles in this issue all relate to this aspect of lighting research. Yoshizawa et al. present a new model for spatial lighting calculations and visualizations, Photon Flow, which focuses on the light field itself rather than surface-bound quantities. Chen et al. propose a grayscale luminance function to determine average luminance and the spatial luminance coefficient. Tsesmelis et al. propose a neural network architecture, DeepLux, for predicting illuminance of indoor scenes in real time. The final two articles focus on spectral power distributions (SPDs). Lokesh et al. present work that also applies neural networks, but their use is to predict changes to SPDs over time. Finally, Royer et al. document a new algorithm for computing large sets of metamers for colour-mixed LED systems. In the coming years, it will be interesting to follow how these methods, and others that are sure to follow, will influence lighting practice and lighting outcomes. Artificial intelligence, machine learning and data science have become key elements of many scientific fields, but the lighting profession – which is not known for rapid change – may have to look outside itself to effectively integrate new metrics, methods, workflows and business models. As Leland Curtis suggests in this issue’s opinion, the future of lighting practice may be very different than what is common today, with a focus on delivering scalable digital technology products instead of projects. I wonder if Gibson and Tyndall, or any of the other researchers whose data contributed to the definition of the lumen, envisioned a future where calculation software could provide realtime, accurate, photorealistic rendering of light in
{"title":"Editorial: The next generation of lighting calculations","authors":"Michael P. Royer","doi":"10.1177/14771535231167999","DOIUrl":"https://doi.org/10.1177/14771535231167999","url":null,"abstract":"It’s been 100 years since Gibson and Tyndall formally proposed the values that were standardized a year later as the CIE spectral luminous efficiency function for photopic vision, V(λ). The 1920s was a decade when several new computing machines were introduced, but before the first introduction of modern electronic computers in the 1940s. Calculations involving the nascent lumen were likely done by hand and were then at the forefront of lighting science. By the 1960s, methods to calculate average horizontal illuminance, such as the zonal cavity method, were available and the subject of scientific research to understand error levels and extend applicability to new situations. With the increasing availability of personal computers in the 1980s and 1990s, new lighting software based on ray tracing models, radiosity models or a combination was introduced to ease the burden of computing lighting quantities, extend computational capabilities to a much wider range of applications and offer rendered images. The performance of lighting calculation software has continued to improve, and in the last several years, it has begun to include better modelling of spectral quantities as well. There’s still room to improve the speed, accuracy and utility of lighting calculations, and the five articles in this issue all relate to this aspect of lighting research. Yoshizawa et al. present a new model for spatial lighting calculations and visualizations, Photon Flow, which focuses on the light field itself rather than surface-bound quantities. Chen et al. propose a grayscale luminance function to determine average luminance and the spatial luminance coefficient. Tsesmelis et al. propose a neural network architecture, DeepLux, for predicting illuminance of indoor scenes in real time. The final two articles focus on spectral power distributions (SPDs). Lokesh et al. present work that also applies neural networks, but their use is to predict changes to SPDs over time. Finally, Royer et al. document a new algorithm for computing large sets of metamers for colour-mixed LED systems. In the coming years, it will be interesting to follow how these methods, and others that are sure to follow, will influence lighting practice and lighting outcomes. Artificial intelligence, machine learning and data science have become key elements of many scientific fields, but the lighting profession – which is not known for rapid change – may have to look outside itself to effectively integrate new metrics, methods, workflows and business models. As Leland Curtis suggests in this issue’s opinion, the future of lighting practice may be very different than what is common today, with a focus on delivering scalable digital technology products instead of projects. I wonder if Gibson and Tyndall, or any of the other researchers whose data contributed to the definition of the lumen, envisioned a future where calculation software could provide realtime, accurate, photorealistic rendering of light in ","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"68 1","pages":"239 - 240"},"PeriodicalIF":2.5,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86125188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-20DOI: 10.1177/14771535231168000
Leland Curtis
{"title":"Opinion: From Projects to Products","authors":"Leland Curtis","doi":"10.1177/14771535231168000","DOIUrl":"https://doi.org/10.1177/14771535231168000","url":null,"abstract":"","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"83 1","pages":"241 - 241"},"PeriodicalIF":2.5,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83989676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-15DOI: 10.1177/14771535231158528
U. Krüger, A. Ferrero, A. Thorseth, V. Mantela, A. Sperling
The general V ( λ ) mismatch index f 1 ′ specifies the mismatch between the relative spectral responsivity of a photometer, and the spectral luminous efficiency function for photopic vision, V ( λ ). A short review of its historical development explains the reasons for the current definition and which adjustments may be helpful in the future. The properties of the current definition are described in detail. It is very likely that photometers will be calibrated with a white light-emitting diode (LED) light source as the reference in the future. This might involve the need for a more appropriate definition of the general V ( λ ) mismatch index, either by using a different normalisation in f 1 ′ for the relative spectral responsivity of the photometer or by introducing a different type of function for assessing the mismatch. On the other hand, the measurement of coloured LEDs is also becoming increasingly important. So, is a single general mismatch index for white and coloured light sources sufficient?
{"title":"General V(λ) mismatch index: History, current state and new ideas","authors":"U. Krüger, A. Ferrero, A. Thorseth, V. Mantela, A. Sperling","doi":"10.1177/14771535231158528","DOIUrl":"https://doi.org/10.1177/14771535231158528","url":null,"abstract":"The general V ( λ ) mismatch index f 1 ′ specifies the mismatch between the relative spectral responsivity of a photometer, and the spectral luminous efficiency function for photopic vision, V ( λ ). A short review of its historical development explains the reasons for the current definition and which adjustments may be helpful in the future. The properties of the current definition are described in detail. It is very likely that photometers will be calibrated with a white light-emitting diode (LED) light source as the reference in the future. This might involve the need for a more appropriate definition of the general V ( λ ) mismatch index, either by using a different normalisation in f 1 ′ for the relative spectral responsivity of the photometer or by introducing a different type of function for assessing the mismatch. On the other hand, the measurement of coloured LEDs is also becoming increasingly important. So, is a single general mismatch index for white and coloured light sources sufficient?","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"35 1","pages":"420 - 432"},"PeriodicalIF":2.5,"publicationDate":"2023-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79718937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-02DOI: 10.1177/14771535231168015
P. Thorns
{"title":"Book review: Lidija Djokic and M. iomir Kostic (2022), Urban Lighting: From Basics to Applications","authors":"P. Thorns","doi":"10.1177/14771535231168015","DOIUrl":"https://doi.org/10.1177/14771535231168015","url":null,"abstract":"","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"1 1","pages":"339 - 339"},"PeriodicalIF":2.5,"publicationDate":"2023-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85568946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.1177/14771535221100261
L. Qin, D. Yang, Ying-Na Weng, AS Leon, Xuefei Shi
This study presents the results of a driving experiment study on spatiotemporal characteristics of drivers’ fixation when entering a tunnel portal with different driving speeds. The study was performed during the daytime in a relatively long tunnel. Six experienced drivers were recruited to participate in the driving experiment. Experimental data of pupil area and fixation point position (from 200 m before the tunnel to the tunnel portal) were collected by non-intrusive eye-tracking equipment for three predetermined vehicle speeds (40 km/h, 60 km/h and 80 km/h). Fixation maps (color-coded maps showing distributed data) were created from fixation point position data to quantify visual behaviour changes. The results demonstrated that vehicle speed has a significant impact on pupil area and fixation zones. Fixation area and average pupil area had a significant negative correlation with vehicle speed during the daytime. Moreover, drivers concentrated more on the tunnel entrance portal, front road pavement and car control wheeling. The results revealed that the relationship between pupil area and vehicle speed fitted an exponential function. Limitations and future directions of the study are also discussed.
{"title":"Tunnel safety: A pilot study investigating drivers’ fixation characteristics when approaching tunnel entrance at different driving speeds","authors":"L. Qin, D. Yang, Ying-Na Weng, AS Leon, Xuefei Shi","doi":"10.1177/14771535221100261","DOIUrl":"https://doi.org/10.1177/14771535221100261","url":null,"abstract":"This study presents the results of a driving experiment study on spatiotemporal characteristics of drivers’ fixation when entering a tunnel portal with different driving speeds. The study was performed during the daytime in a relatively long tunnel. Six experienced drivers were recruited to participate in the driving experiment. Experimental data of pupil area and fixation point position (from 200 m before the tunnel to the tunnel portal) were collected by non-intrusive eye-tracking equipment for three predetermined vehicle speeds (40 km/h, 60 km/h and 80 km/h). Fixation maps (color-coded maps showing distributed data) were created from fixation point position data to quantify visual behaviour changes. The results demonstrated that vehicle speed has a significant impact on pupil area and fixation zones. Fixation area and average pupil area had a significant negative correlation with vehicle speed during the daytime. Moreover, drivers concentrated more on the tunnel entrance portal, front road pavement and car control wheeling. The results revealed that the relationship between pupil area and vehicle speed fitted an exponential function. Limitations and future directions of the study are also discussed.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"64 1","pages":"155 - 169"},"PeriodicalIF":2.5,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84421637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-31DOI: 10.1177/14771535231168492
{"title":"Corrigendum to Four minutes might not be enough for color temperature of light to affect subjective sleepiness, mental effort, and light ratings","authors":"","doi":"10.1177/14771535231168492","DOIUrl":"https://doi.org/10.1177/14771535231168492","url":null,"abstract":"","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"5 1","pages":"340 - 340"},"PeriodicalIF":2.5,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81657866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-20DOI: 10.1177/14771535231153780
{"title":"Opinion: Development of lighting research in China","authors":"","doi":"10.1177/14771535231153780","DOIUrl":"https://doi.org/10.1177/14771535231153780","url":null,"abstract":"","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"75 1","pages":"104 - 104"},"PeriodicalIF":2.5,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91344417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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