Pub Date : 2022-04-26DOI: 10.1177/14771535221077881
T. Hegemann, J. Balasus, Q. Trinh, A. Herzog, TQ Khanh
Precise determination of the photosynthetic photon flux density (PPFD) is important for illumination in modern horticultural systems. This paper presents two methods to calculate the PPFD of daylight spectra using low cost optic sensors. The first method uses the spectral sensitivity functions of spectral sensors to recreate the quantum sensitivity curve of quantum sensors. Two sets of spectral sensitivity functions are compared. The second method calculates the PPFD based on the calculated correlated colour temperature and a spectral reconstruction using the CIE daylight model. It is demonstrated that all methods offer a useful estimation of the PPFD with correspondingly similar daylight spectra, but the supposedly simpler method, which is based on weighting of the individual channels, is more stable against deviations from the CIE daylight model.
{"title":"Using spectral sensors to determine photosynthetic photon flux density in daylight – A theoretical approach","authors":"T. Hegemann, J. Balasus, Q. Trinh, A. Herzog, TQ Khanh","doi":"10.1177/14771535221077881","DOIUrl":"https://doi.org/10.1177/14771535221077881","url":null,"abstract":"Precise determination of the photosynthetic photon flux density (PPFD) is important for illumination in modern horticultural systems. This paper presents two methods to calculate the PPFD of daylight spectra using low cost optic sensors. The first method uses the spectral sensitivity functions of spectral sensors to recreate the quantum sensitivity curve of quantum sensors. Two sets of spectral sensitivity functions are compared. The second method calculates the PPFD based on the calculated correlated colour temperature and a spectral reconstruction using the CIE daylight model. It is demonstrated that all methods offer a useful estimation of the PPFD with correspondingly similar daylight spectra, but the supposedly simpler method, which is based on weighting of the individual channels, is more stable against deviations from the CIE daylight model.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"65 1 1","pages":"429 - 440"},"PeriodicalIF":2.5,"publicationDate":"2022-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86385226","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 : 2022-04-21DOI: 10.1177/14771535211049816
Y. Akashi, Y. Kuno, K. Murakami, M. Inatani, T. Aoki
In ageing societies, it is necessary to make the visual environment more appropriate for the elderly so that they can maintain visual performance as long as possible. To this end, we aimed at developing guidelines to determine appropriate adaptation luminance and luminance contrast for given letter sizes for the elderly. In this study, we first measured the contrast sensitivities of older participants. Second, we conducted an experiment in which the same participants evaluated the degrees of readability of Japanese sentences with various letter sizes, luminance contrasts and adaptation luminances. Based on the evaluations, we developed a readability model consisting of equal-readability-level contour lines that represent the average of older peoples’ readability scores. From the model, we found we could improve readability by increasing adaptation luminance while the adaptation luminance was lower than 200 cd/m2. However, an increase in luminance contrast became more helpful to improve readability than an increase in adaptation luminance when the adaptation luminance was higher than 200 cd/m2. We also found large individual deviations in readability evaluation among older participants depending on the contrast sensitivity. We divided the participants into three groups based on their contrast sensitivity levels and compared readability models among the three groups.
{"title":"A readability model of letters with various letter size, luminance contrast and adaptation luminance levels for seniors","authors":"Y. Akashi, Y. Kuno, K. Murakami, M. Inatani, T. Aoki","doi":"10.1177/14771535211049816","DOIUrl":"https://doi.org/10.1177/14771535211049816","url":null,"abstract":"In ageing societies, it is necessary to make the visual environment more appropriate for the elderly so that they can maintain visual performance as long as possible. To this end, we aimed at developing guidelines to determine appropriate adaptation luminance and luminance contrast for given letter sizes for the elderly. In this study, we first measured the contrast sensitivities of older participants. Second, we conducted an experiment in which the same participants evaluated the degrees of readability of Japanese sentences with various letter sizes, luminance contrasts and adaptation luminances. Based on the evaluations, we developed a readability model consisting of equal-readability-level contour lines that represent the average of older peoples’ readability scores. From the model, we found we could improve readability by increasing adaptation luminance while the adaptation luminance was lower than 200 cd/m2. However, an increase in luminance contrast became more helpful to improve readability than an increase in adaptation luminance when the adaptation luminance was higher than 200 cd/m2. We also found large individual deviations in readability evaluation among older participants depending on the contrast sensitivity. We divided the participants into three groups based on their contrast sensitivity levels and compared readability models among the three groups.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"1 1","pages":"475 - 495"},"PeriodicalIF":2.5,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74655039","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 : 2022-04-17DOI: 10.1177/14771535211063624
H. Garg, DS Bisht, K. Sharma, V. Kumar, K. Kaur, N. Garg
Daylighting using natural illumination system (NILS) is gaining popularity due to transition to the renewable and non-conventional energy resources. In the proposed work, optomechanical design, numerical analysis, experimentation and integration of a modular Fresnel lens for NILS to effectively harness the sunlight is discussed. The modular and integrated design delivers uniform light at the receiving area of the daylight transportation system. This modular Fresnel lens is a combination of linear Fresnel lenses designed to offer a moderate concentration ratio to avoid hot spots. The distribution of solar radiation on the focal plane/entry section of the plastic optical fibre bundle (daylight transportation system) is simulated using the ray-trace technique for a lens system with a concentration ratio of 81. The irradiance distributions at the focal plane were found uniform with a radiometric and photometric transmission efficiency of 72.45% and 85.96%, respectively, for the lens element. The overall photometric transmission efficiency of the system with 10 m long plastic/acrylic optical fibre cable was found as 40.97%.
{"title":"Analysis, evaluation and integration of modular natural illumination system using a rectangular Fresnel lens for high performance","authors":"H. Garg, DS Bisht, K. Sharma, V. Kumar, K. Kaur, N. Garg","doi":"10.1177/14771535211063624","DOIUrl":"https://doi.org/10.1177/14771535211063624","url":null,"abstract":"Daylighting using natural illumination system (NILS) is gaining popularity due to transition to the renewable and non-conventional energy resources. In the proposed work, optomechanical design, numerical analysis, experimentation and integration of a modular Fresnel lens for NILS to effectively harness the sunlight is discussed. The modular and integrated design delivers uniform light at the receiving area of the daylight transportation system. This modular Fresnel lens is a combination of linear Fresnel lenses designed to offer a moderate concentration ratio to avoid hot spots. The distribution of solar radiation on the focal plane/entry section of the plastic optical fibre bundle (daylight transportation system) is simulated using the ray-trace technique for a lens system with a concentration ratio of 81. The irradiance distributions at the focal plane were found uniform with a radiometric and photometric transmission efficiency of 72.45% and 85.96%, respectively, for the lens element. The overall photometric transmission efficiency of the system with 10 m long plastic/acrylic optical fibre cable was found as 40.97%.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"14 1","pages":"554 - 570"},"PeriodicalIF":2.5,"publicationDate":"2022-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84293205","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 : 2022-04-11DOI: 10.1177/14771535211059719
C-S Wu, Shih-Kang Lin, C-C Sun, M. Tsai, T.-H. Yang, Y. Yu
In this paper, a bicycle light-emitting diode (LED) headlamp is design for the purpose of meeting the regulation and removing the unwanted reflection of some specific parts. In addition to the optical design of the headlamp, a three-dimensional mask is designed to block the LED light source to remove the specific unwanted light on the front tyre of the bicycle and then reduce the glare effect to the rider. The experimental results show that the 3D mask can effectively eliminate 97.7% of the unwanted light on the wheel of the bicycle and keeps 98.6% of the original illuminance at the A point of the K-mark regulation. The proposed mask approach will be helpful to the design by using LED as a light source.
{"title":"Headlamp design with an additional midfield mask for removal of specific illumination including glare","authors":"C-S Wu, Shih-Kang Lin, C-C Sun, M. Tsai, T.-H. Yang, Y. Yu","doi":"10.1177/14771535211059719","DOIUrl":"https://doi.org/10.1177/14771535211059719","url":null,"abstract":"In this paper, a bicycle light-emitting diode (LED) headlamp is design for the purpose of meeting the regulation and removing the unwanted reflection of some specific parts. In addition to the optical design of the headlamp, a three-dimensional mask is designed to block the LED light source to remove the specific unwanted light on the front tyre of the bicycle and then reduce the glare effect to the rider. The experimental results show that the 3D mask can effectively eliminate 97.7% of the unwanted light on the wheel of the bicycle and keeps 98.6% of the original illuminance at the A point of the K-mark regulation. The proposed mask approach will be helpful to the design by using LED as a light source.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"164 1","pages":"497 - 508"},"PeriodicalIF":2.5,"publicationDate":"2022-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88807902","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 : 2022-04-01DOI: 10.1177/14771535221083429
T. Goodman
Listening to the evening news bulletin recently, I was struck how much of the reporting could be directly linked to measurement, and how much we take for granted our ability to quantify all manner of things in a meaningful, consistent and reproducible manner. Of course, much of what we measure is relatively straightforward: counting the number of people in hospital with Covidrelated complications, or recording the warmest New Year’s Day ever in the UK, for example, can both be done without the need for complicated measurement equipment or analysis (although the latter does require good calibration of weather station thermometers). But what about more complex measurements, such as the amount of CO2 in the atmosphere? Reliable and meaningful data in these cases are only possible as a result of international collaborations to collect and process information gathered from a wide range of different sensors, all of which must be linked to a consistent set of measurement units. As our need to understand and quantify the impact of human activity on the environment increases, so too does our need for relevant and reliable systems of measurement. Light and lighting present their own measurement challenges. Those, too, are becoming more complex as our understanding of the impact of optical radiation on human health and wellbeing improves, and our desire to use the energy consumed by lighting more effectively increases. No longer is it enough to know (i.e. measure) the amount of visible light delivered for a given amount of energy. We also need to consider how that light might affect our sleep-wake cycle, our mood, our ability to concentrate and so on. Our understanding of the wide-reaching impact of optical radiation on human biology and behaviour is still in its infancy and there is much that still needs to be investigated. In parallel with better knowledge comes a desire to translate research findings into improved lighting products and practice. And that in turn means we need a measurement framework that not only allows us to collect and analyse information about the relevant properties of “lighting”, but also to communicate and quantify those properties in a meaningful and understandable way. Any such measurement system must also be compliant with the International System of Units (SI), which is essential to enable traceable measurements and the establishment of international standards and guidelines. I hope all those involved in this important area of research will continue to keep the ultimate need for a relevant and reliable measurement system in mind and continue their collaborations to achieve this goal. To quote Lord Kelvin: “When you can measure what you are speaking about, and express it in numbers, you know something about it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science.”
{"title":"Editorial: The measure of light","authors":"T. Goodman","doi":"10.1177/14771535221083429","DOIUrl":"https://doi.org/10.1177/14771535221083429","url":null,"abstract":"Listening to the evening news bulletin recently, I was struck how much of the reporting could be directly linked to measurement, and how much we take for granted our ability to quantify all manner of things in a meaningful, consistent and reproducible manner. Of course, much of what we measure is relatively straightforward: counting the number of people in hospital with Covidrelated complications, or recording the warmest New Year’s Day ever in the UK, for example, can both be done without the need for complicated measurement equipment or analysis (although the latter does require good calibration of weather station thermometers). But what about more complex measurements, such as the amount of CO2 in the atmosphere? Reliable and meaningful data in these cases are only possible as a result of international collaborations to collect and process information gathered from a wide range of different sensors, all of which must be linked to a consistent set of measurement units. As our need to understand and quantify the impact of human activity on the environment increases, so too does our need for relevant and reliable systems of measurement. Light and lighting present their own measurement challenges. Those, too, are becoming more complex as our understanding of the impact of optical radiation on human health and wellbeing improves, and our desire to use the energy consumed by lighting more effectively increases. No longer is it enough to know (i.e. measure) the amount of visible light delivered for a given amount of energy. We also need to consider how that light might affect our sleep-wake cycle, our mood, our ability to concentrate and so on. Our understanding of the wide-reaching impact of optical radiation on human biology and behaviour is still in its infancy and there is much that still needs to be investigated. In parallel with better knowledge comes a desire to translate research findings into improved lighting products and practice. And that in turn means we need a measurement framework that not only allows us to collect and analyse information about the relevant properties of “lighting”, but also to communicate and quantify those properties in a meaningful and understandable way. Any such measurement system must also be compliant with the International System of Units (SI), which is essential to enable traceable measurements and the establishment of international standards and guidelines. I hope all those involved in this important area of research will continue to keep the ultimate need for a relevant and reliable measurement system in mind and continue their collaborations to achieve this goal. To quote Lord Kelvin: “When you can measure what you are speaking about, and express it in numbers, you know something about it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science.”","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"200 1","pages":"99 - 99"},"PeriodicalIF":2.5,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76965545","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 : 2022-04-01DOI: 10.1177/14771535211040973
AK Jägerbrand, D. Gašparovský, CA Bouroussis, L. Schlangen, S. Lau, M. Donners
Research on light pollution and artificial light at night (ALAN) has undergone rapid evolution, expanding from primarily astronomy into new disciplines. A keyword search in Scopus reveals a 466% increase from the number of papers published before 2011 (326) to those published between 2011 and 2020 (1846). Similarly, the number of papers in Lighting Research and Technology on these topics increased during the same period from 4 to 11. It is well known that ALAN can have adverse effects on surroundings in terms of sky glow, light trespass and discomfort glare, degradation of astronomical observations, health impacts and disturbance of ecosystems. Observatories need special curfews and light-protected areas to safeguard their ability to observe the stars. Nature reserves, stargazing locations and areas designated as protected habitats for rare and endangered species need to employ strict principles for design and use of light and lighting to prevent unwanted impacts. Hence, light pollution needs to be adequately addressed and counteracted by the lighting research community. In November 2020, a workshop on obtrusive light, arranged by Divisions 2 and 4 of the International Commission on Illumination (CIE) and the Technical University of Ostrava, convened researchers and professionals from different disciplines to discuss future research directions. In this correspondence we highlight six areas that were deemed important to improve the scientific and metrology basis and update international standards and guidelines to address global concerns with respect to light pollution. 1. Terminology. The CIE International Lighting Vocabulary defines light pollution as the ‘sum total of all adverse effects of artificial light’, whereas obtrusive light is defined as ‘spill light which, because of quantitative or directional attributes, gives rise to annoyance, discomfort, distraction, or a reduction in ability to see essential information such as transport signals’. However, it is unclear (i) whether artificial light must always be considered a pollutant, (ii) whether light pollution only takes place at night, (iii) what the difference is between light pollution and obtrusive light and (iv) whether the current effect-based definitions suffice to describe these terms. A commonly accepted and scientifically more precise terminology should be established to avoid confusion and serve various disciplines.
{"title":"Correspondence: Obtrusive light, light pollution and sky glow: Areas for research, development and standardisation","authors":"AK Jägerbrand, D. Gašparovský, CA Bouroussis, L. Schlangen, S. Lau, M. Donners","doi":"10.1177/14771535211040973","DOIUrl":"https://doi.org/10.1177/14771535211040973","url":null,"abstract":"Research on light pollution and artificial light at night (ALAN) has undergone rapid evolution, expanding from primarily astronomy into new disciplines. A keyword search in Scopus reveals a 466% increase from the number of papers published before 2011 (326) to those published between 2011 and 2020 (1846). Similarly, the number of papers in Lighting Research and Technology on these topics increased during the same period from 4 to 11. It is well known that ALAN can have adverse effects on surroundings in terms of sky glow, light trespass and discomfort glare, degradation of astronomical observations, health impacts and disturbance of ecosystems. Observatories need special curfews and light-protected areas to safeguard their ability to observe the stars. Nature reserves, stargazing locations and areas designated as protected habitats for rare and endangered species need to employ strict principles for design and use of light and lighting to prevent unwanted impacts. Hence, light pollution needs to be adequately addressed and counteracted by the lighting research community. In November 2020, a workshop on obtrusive light, arranged by Divisions 2 and 4 of the International Commission on Illumination (CIE) and the Technical University of Ostrava, convened researchers and professionals from different disciplines to discuss future research directions. In this correspondence we highlight six areas that were deemed important to improve the scientific and metrology basis and update international standards and guidelines to address global concerns with respect to light pollution. 1. Terminology. The CIE International Lighting Vocabulary defines light pollution as the ‘sum total of all adverse effects of artificial light’, whereas obtrusive light is defined as ‘spill light which, because of quantitative or directional attributes, gives rise to annoyance, discomfort, distraction, or a reduction in ability to see essential information such as transport signals’. However, it is unclear (i) whether artificial light must always be considered a pollutant, (ii) whether light pollution only takes place at night, (iii) what the difference is between light pollution and obtrusive light and (iv) whether the current effect-based definitions suffice to describe these terms. A commonly accepted and scientifically more precise terminology should be established to avoid confusion and serve various disciplines.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"47 1","pages":"191 - 194"},"PeriodicalIF":2.5,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88028553","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 : 2022-04-01DOI: 10.1177/14771535221083430
R. Najjar
Many of us take sharp vision for granted. Yet, for images to be perceived clearly, the developing eye undergoes emmetropization, a visually-guided process whereby ocular growth is controlled and harmonised with the focal power of the eye to minimise refractive error and maximise visual acuity. Flaws in emmetropization can lead to refractive errors and blurred vision. Myopia, or near-sightedness, is a refractive error characterised by the blurred vision of objects when viewed at a distance. It is commonly due to excessive ocular axial growth leading to images being focussed in front of the retina. Myopia is more than an inconvenience that can be corrected by spectacles or contact lenses, it’s a highly prevalent sightthreatening disease that is projected to affect 50% of the world population by 2050, becoming the leading cause of irreversible blindness. Genetics play a part, but cannot explain the rapid increase in global myopia prevalence over the recent decades. The visual environment affects emmetropization and myopia development. For instance, increased time outdoors has been shown to be protective against myopia in children. The exact mechanisms underlying the antimyopiagenic effect of time outdoors are not fully understood, but could be due to a variety of synergetic factors such as reduction in accommodative fatigue, increase in spatial frequency in outdoor sceneries, and changes in the intensity and spectral features of light/sunlight, which lack in artificial lighting. While epidemiological studies highlight associations between myopia prevention and high intensity light experienced outdoors, substantial evidence in various animal models support a protective role of high intensity light against experimental myopia, through increases in retinal dopamine and changes in other ocular neuromodulators. These findings prompted the development of outdoor programs for myopia prevention. Nevertheless, increasing time outdoors is challenging, particularly during school years, given the cultural commitment to educational success in many parts of the world. Passive exposure to higher levels of light indoors (e.g., ∼500 lx of fluorescent light in classrooms) was also successful in lowering myopia onset. Taken together these findings suggest that increasing the intensity of the lighting environment, even intermittently, may be effective in preventing or delaying the onset of myopia. Emmetropization is also dependent on the spectral content of the lighting environment, with protective effects against myopia attributable to either short or long wavelength visible light, depending on the animal model. Today, the optimal intensity and spectral composition of light for emmetropization remains unidentified in humans, yet epidemiological and experimental studies provide evidence to suggest that the tailoring of architectural lighting at homes or schools, in a synergetic manner with other environmental features, may one day offer a passive, cost-effective and sa
{"title":"Opinion: Tailoring the lighting environment for a healthier ocular growth","authors":"R. Najjar","doi":"10.1177/14771535221083430","DOIUrl":"https://doi.org/10.1177/14771535221083430","url":null,"abstract":"Many of us take sharp vision for granted. Yet, for images to be perceived clearly, the developing eye undergoes emmetropization, a visually-guided process whereby ocular growth is controlled and harmonised with the focal power of the eye to minimise refractive error and maximise visual acuity. Flaws in emmetropization can lead to refractive errors and blurred vision. Myopia, or near-sightedness, is a refractive error characterised by the blurred vision of objects when viewed at a distance. It is commonly due to excessive ocular axial growth leading to images being focussed in front of the retina. Myopia is more than an inconvenience that can be corrected by spectacles or contact lenses, it’s a highly prevalent sightthreatening disease that is projected to affect 50% of the world population by 2050, becoming the leading cause of irreversible blindness. Genetics play a part, but cannot explain the rapid increase in global myopia prevalence over the recent decades. The visual environment affects emmetropization and myopia development. For instance, increased time outdoors has been shown to be protective against myopia in children. The exact mechanisms underlying the antimyopiagenic effect of time outdoors are not fully understood, but could be due to a variety of synergetic factors such as reduction in accommodative fatigue, increase in spatial frequency in outdoor sceneries, and changes in the intensity and spectral features of light/sunlight, which lack in artificial lighting. While epidemiological studies highlight associations between myopia prevention and high intensity light experienced outdoors, substantial evidence in various animal models support a protective role of high intensity light against experimental myopia, through increases in retinal dopamine and changes in other ocular neuromodulators. These findings prompted the development of outdoor programs for myopia prevention. Nevertheless, increasing time outdoors is challenging, particularly during school years, given the cultural commitment to educational success in many parts of the world. Passive exposure to higher levels of light indoors (e.g., ∼500 lx of fluorescent light in classrooms) was also successful in lowering myopia onset. Taken together these findings suggest that increasing the intensity of the lighting environment, even intermittently, may be effective in preventing or delaying the onset of myopia. Emmetropization is also dependent on the spectral content of the lighting environment, with protective effects against myopia attributable to either short or long wavelength visible light, depending on the animal model. Today, the optimal intensity and spectral composition of light for emmetropization remains unidentified in humans, yet epidemiological and experimental studies provide evidence to suggest that the tailoring of architectural lighting at homes or schools, in a synergetic manner with other environmental features, may one day offer a passive, cost-effective and sa","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"4 1","pages":"100 - 100"},"PeriodicalIF":2.5,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75553726","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 : 2022-03-01DOI: 10.1177/14771535211053960
P. Zhang, M. Li, Y. Huang, Q. Dai
Cuttle has proposed to use mean room surface exitance (MRSE) as a measure of spatial brightness for interior lighting design. One problem hindering the adoption of MRSE is the lack of a practical field-measurement method with verified accuracy. Although Cuttle suggested that MRSE can be estimated by measuring the illuminance caused by indirect light from a position that takes up an overall view of the room, no evidence was provided and that approach was later proved to be inaccurate. This paper presents a newly developed approach for measuring MRSE in a conventional cuboid space, simply by placing an illuminance meter at specific locations, recording the illuminance values caused by indirect light and calculating the weighted average of those values. The weighting parameters can be determined based on the geometry of the space. Furthermore, the rationality of such an MRSE-measurement method is provided, and its accuracy is verified by using Radiance lighting simulation, which suggests an error of less than 10%. Our proposed method shows that measuring MRSE in the field is feasible.
{"title":"A practical method for field measurement of mean room surface exitance","authors":"P. Zhang, M. Li, Y. Huang, Q. Dai","doi":"10.1177/14771535211053960","DOIUrl":"https://doi.org/10.1177/14771535211053960","url":null,"abstract":"Cuttle has proposed to use mean room surface exitance (MRSE) as a measure of spatial brightness for interior lighting design. One problem hindering the adoption of MRSE is the lack of a practical field-measurement method with verified accuracy. Although Cuttle suggested that MRSE can be estimated by measuring the illuminance caused by indirect light from a position that takes up an overall view of the room, no evidence was provided and that approach was later proved to be inaccurate. This paper presents a newly developed approach for measuring MRSE in a conventional cuboid space, simply by placing an illuminance meter at specific locations, recording the illuminance values caused by indirect light and calculating the weighted average of those values. The weighting parameters can be determined based on the geometry of the space. Furthermore, the rationality of such an MRSE-measurement method is provided, and its accuracy is verified by using Radiance lighting simulation, which suggests an error of less than 10%. Our proposed method shows that measuring MRSE in the field is feasible.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"40 1","pages":"674 - 689"},"PeriodicalIF":2.5,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88076523","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 : 2022-02-25DOI: 10.1177/14771535211058202
C. Yu, E. Eisemann, S. Pont
Chromatic properties of the effective light in a space are hard to predict, measure and visualise. This is due to complex interactions between materials and illuminants. Here, we describe, measure and visualise the effects of inter-reflections on the structure of the physical light field for diffusely scattering scenes. The spectral properties of inter-reflections vary as a function of the number of bounces they went through. Via a computational model, these spectral variations were found to be systematic and correspond with brightness, saturation and hue shifts. We extended our light-field methods to measure and understand these spectral effects on the first-order properties of light fields, the light density and light vector. We tested the model via a set of computer renderings and cubic spectral illuminance measurements in mock-up rooms under different furnishing scenarios for two types of illuminants. The predicted spectral variations were confirmed and indeed varied systematically within the resulting light field, spatially and directionally. Inter-reflections predominantly affect the light density spectrum and have less impact on the light vector spectrum. It is important to consider these differential effects for their consequences on the colour rendering of 3-dimensional objects and people.
{"title":"Effects of inter-reflections on the chromatic structure of the light field","authors":"C. Yu, E. Eisemann, S. Pont","doi":"10.1177/14771535211058202","DOIUrl":"https://doi.org/10.1177/14771535211058202","url":null,"abstract":"Chromatic properties of the effective light in a space are hard to predict, measure and visualise. This is due to complex interactions between materials and illuminants. Here, we describe, measure and visualise the effects of inter-reflections on the structure of the physical light field for diffusely scattering scenes. The spectral properties of inter-reflections vary as a function of the number of bounces they went through. Via a computational model, these spectral variations were found to be systematic and correspond with brightness, saturation and hue shifts. We extended our light-field methods to measure and understand these spectral effects on the first-order properties of light fields, the light density and light vector. We tested the model via a set of computer renderings and cubic spectral illuminance measurements in mock-up rooms under different furnishing scenarios for two types of illuminants. The predicted spectral variations were confirmed and indeed varied systematically within the resulting light field, spatially and directionally. Inter-reflections predominantly affect the light density spectrum and have less impact on the light vector spectrum. It is important to consider these differential effects for their consequences on the colour rendering of 3-dimensional objects and people.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"52 1","pages":"218 - 236"},"PeriodicalIF":2.5,"publicationDate":"2022-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90893346","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 : 2022-02-01DOI: 10.1177/14771535211038292
Y. He, X. Zhang, L. Quan, D. Shi, Y. Zhang
This study presents a novel model to estimate the sky luminance distribution (SLD) using the information method based on the research results of the SLD and atmospheric optics theory. The ant colony system of complex optimisation heuristic algorithms is used to analyse and optimise the influencing factors of sky luminance. The SLD using the information method is universal and is not related to geographical, latitudinal or climatic conditions. First, a simple and clear sky classification method is proposed. Then, a model framework is constructed. Using the ant colony system, the effects of the sky luminance elements are analysed and optimised, and numerical expressions for the coefficients of the relative luminance distribution are obtained. Finally, the proposed model is compared with other sky models (Perez’s model, the Commission Internationale de l’Eclairage model and Igawa’s all-sky model). The results show that the proposed model offers significant advantages for generating a universal SLD. Moreover, the information method SLD model can significantly enrich the coverage of the reference sky, and it avoids the shortcomings of existing sky models.
{"title":"Sky luminance distribution model based on the information method and ant colony system","authors":"Y. He, X. Zhang, L. Quan, D. Shi, Y. Zhang","doi":"10.1177/14771535211038292","DOIUrl":"https://doi.org/10.1177/14771535211038292","url":null,"abstract":"This study presents a novel model to estimate the sky luminance distribution (SLD) using the information method based on the research results of the SLD and atmospheric optics theory. The ant colony system of complex optimisation heuristic algorithms is used to analyse and optimise the influencing factors of sky luminance. The SLD using the information method is universal and is not related to geographical, latitudinal or climatic conditions. First, a simple and clear sky classification method is proposed. Then, a model framework is constructed. Using the ant colony system, the effects of the sky luminance elements are analysed and optimised, and numerical expressions for the coefficients of the relative luminance distribution are obtained. Finally, the proposed model is compared with other sky models (Perez’s model, the Commission Internationale de l’Eclairage model and Igawa’s all-sky model). The results show that the proposed model offers significant advantages for generating a universal SLD. Moreover, the information method SLD model can significantly enrich the coverage of the reference sky, and it avoids the shortcomings of existing sky models.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"10 1","pages":"413 - 428"},"PeriodicalIF":2.5,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87591936","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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