Pub Date : 2022-10-26DOI: 10.1177/14771535221088803
L. Xia, N. Xiao, X. Liu, T. Zhang, R. Xu, F. Li
The cubic illumination metre has been taken as the most thorough and practical tool for the field measurement of vector illuminance so far. However, uncertainty in the measurement of scalar illuminance has influenced its reliability. This study determined how the errors of the existing approaches were generated using illustrations and simulations based on the illuminance solid concept. Following the error analysis of the existing approaches, potential alternative solutions for improving its accuracy were proposed. This study can help pave the way for developing more accurate vector illuminance-based metrics in natural lighting environments using a cubic metre.
{"title":"Determining scalar illuminance from cubic illuminance data. Part 1: Error tracing","authors":"L. Xia, N. Xiao, X. Liu, T. Zhang, R. Xu, F. Li","doi":"10.1177/14771535221088803","DOIUrl":"https://doi.org/10.1177/14771535221088803","url":null,"abstract":"The cubic illumination metre has been taken as the most thorough and practical tool for the field measurement of vector illuminance so far. However, uncertainty in the measurement of scalar illuminance has influenced its reliability. This study determined how the errors of the existing approaches were generated using illustrations and simulations based on the illuminance solid concept. Following the error analysis of the existing approaches, potential alternative solutions for improving its accuracy were proposed. This study can help pave the way for developing more accurate vector illuminance-based metrics in natural lighting environments using a cubic metre.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2022-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84256740","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 : 2022-09-29DOI: 10.1177/14771535221126413
P. Boyce, Hm Brandston, C. Cuttle
Indoor lighting standards were first introduced as a means to ensure the efficient performance of visual tasks in workplaces. Their scope soon expanded to cover a wider range of applications as well as visual discomfort. They thus became a means to eliminate bad lighting, and in this they have been successful. However, now they are often seen as a restriction on the freedom of lighting practitioners to develop alternative designs. This is partly because standards have been issued for applications where there are no critical visual tasks, and partly because the conventional design procedure ensuring compliance with standards assumes a regular array of luminaires. Three steps are proposed for overcoming this problem. The first is to separate lighting recommendations into standards and guidance. Standards should be legally enforceable and devoted to eliminating bad lighting. Promotion of good lighting should be achieved by applications-specific guidance documents. The second is to change the metric used in standards from task illuminance to ambient illuminance, from lighting the task to lighting the space. The third is to change the design method used from the lumen method to the lighting design objectives procedure.
{"title":"Indoor lighting standards and their role in lighting practice","authors":"P. Boyce, Hm Brandston, C. Cuttle","doi":"10.1177/14771535221126413","DOIUrl":"https://doi.org/10.1177/14771535221126413","url":null,"abstract":"Indoor lighting standards were first introduced as a means to ensure the efficient performance of visual tasks in workplaces. Their scope soon expanded to cover a wider range of applications as well as visual discomfort. They thus became a means to eliminate bad lighting, and in this they have been successful. However, now they are often seen as a restriction on the freedom of lighting practitioners to develop alternative designs. This is partly because standards have been issued for applications where there are no critical visual tasks, and partly because the conventional design procedure ensuring compliance with standards assumes a regular array of luminaires. Three steps are proposed for overcoming this problem. The first is to separate lighting recommendations into standards and guidance. Standards should be legally enforceable and devoted to eliminating bad lighting. Promotion of good lighting should be achieved by applications-specific guidance documents. The second is to change the metric used in standards from task illuminance to ambient illuminance, from lighting the task to lighting the space. The third is to change the design method used from the lumen method to the lighting design objectives procedure.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80915359","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 : 2022-09-28DOI: 10.1177/14771535221123230
P. Chen, A. Wang, L. Wang, Y. Wu, J. Yu
The evaluation of the spatial luminance coefficient, Feu, and average luminance, Lav, can improve the lighting quality from both subjective and objective aspects. In the design survey, the determination of these indicators relies on the manual sampling of the luminance of measurement points, which is time-consuming and labour-intensive. This article proposes a grayscale−luminance converting polynomial function, and a method for the determination of Feu and Lav from digital images via the function. The acceptability index, Nallow, is created as the key parameter of the polynomial function, which reduces the number of required measurement points to 9. Taking visual comfort as the criterion, three types of low-contrast working conditions with different luminance distributions – namely an actual scene, simulated scenes and experimental scenes – were set, the luminance ratios of which were less than 100 and the luminance of which was less than 1000 cd/m2. To minimise the error to within 10%, the piecewise function of Nallow determined by the luminance ratio was constructed, which is obtained via the data verification and correction of 20 working conditions. The experimental results of a test scene demonstrate that the accuracies of Feu and Lav produced by the proposed polynomial function were better than those produced by an exponential function.
{"title":"Grayscale−luminance converting polynomial function for digital images to determine Feu and Lav in a low-contrast artificial lit space","authors":"P. Chen, A. Wang, L. Wang, Y. Wu, J. Yu","doi":"10.1177/14771535221123230","DOIUrl":"https://doi.org/10.1177/14771535221123230","url":null,"abstract":"The evaluation of the spatial luminance coefficient, Feu, and average luminance, Lav, can improve the lighting quality from both subjective and objective aspects. In the design survey, the determination of these indicators relies on the manual sampling of the luminance of measurement points, which is time-consuming and labour-intensive. This article proposes a grayscale−luminance converting polynomial function, and a method for the determination of Feu and Lav from digital images via the function. The acceptability index, Nallow, is created as the key parameter of the polynomial function, which reduces the number of required measurement points to 9. Taking visual comfort as the criterion, three types of low-contrast working conditions with different luminance distributions – namely an actual scene, simulated scenes and experimental scenes – were set, the luminance ratios of which were less than 100 and the luminance of which was less than 1000 cd/m2. To minimise the error to within 10%, the piecewise function of Nallow determined by the luminance ratio was constructed, which is obtained via the data verification and correction of 20 working conditions. The experimental results of a test scene demonstrate that the accuracies of Feu and Lav produced by the proposed polynomial function were better than those produced by an exponential function.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77650272","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 : 2022-09-28DOI: 10.1177/14771535221120350
L. Schlangen, S. Belgers, R. Cuijpers, B. Zandi, I. Heynderickx
{"title":"Correspondence: Designing and specifying light for melatonin suppression, non-visual responses and integrative lighting solutions – establishing a proper bright day, dim night metrology","authors":"L. Schlangen, S. Belgers, R. Cuijpers, B. Zandi, I. Heynderickx","doi":"10.1177/14771535221120350","DOIUrl":"https://doi.org/10.1177/14771535221120350","url":null,"abstract":"","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89606036","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 : 2022-09-22DOI: 10.1177/14771535221124082
M. Tanaka, S. Amari, T. Horiuchi
Although a physical gloss exists as a physically measurable index, people can also perceive a perceptual gloss on object surfaces. However, the physical gloss does not always match the perceptual gloss. Because the physical gloss is calculated based only on the specular gloss and does not reflect other physical features that affect the perceptual gloss. Thus, we analysed the relationships between physical features and perceptual gloss by measuring many physical properties of object surfaces, including their physical gloss. We prepared 127 flat objects comprising three materials: paper, resin and metal plating. The perceptual gloss was visually evaluated for observation angles of 20°, 60° and 85° using a magnitude estimation method. Multiple measurements were conducted to obtain physical features such as the gloss unit (GU), haze, distinctness of image and high dynamic range luminance. We then constructed prediction models for the perceptual gloss using these physical features and multiple regression analyses. By combining these multiple physical quantities and using the GU in the power scale, the prediction accuracy was improved. By the optimal power index (0.33 for physical gloss in the common prediction model, independent of the observation angle), we found that human gloss perception may be related to brightness perception.
{"title":"Prediction model for perceptual gloss by physical measurement of flat objects","authors":"M. Tanaka, S. Amari, T. Horiuchi","doi":"10.1177/14771535221124082","DOIUrl":"https://doi.org/10.1177/14771535221124082","url":null,"abstract":"Although a physical gloss exists as a physically measurable index, people can also perceive a perceptual gloss on object surfaces. However, the physical gloss does not always match the perceptual gloss. Because the physical gloss is calculated based only on the specular gloss and does not reflect other physical features that affect the perceptual gloss. Thus, we analysed the relationships between physical features and perceptual gloss by measuring many physical properties of object surfaces, including their physical gloss. We prepared 127 flat objects comprising three materials: paper, resin and metal plating. The perceptual gloss was visually evaluated for observation angles of 20°, 60° and 85° using a magnitude estimation method. Multiple measurements were conducted to obtain physical features such as the gloss unit (GU), haze, distinctness of image and high dynamic range luminance. We then constructed prediction models for the perceptual gloss using these physical features and multiple regression analyses. By combining these multiple physical quantities and using the GU in the power scale, the prediction accuracy was improved. By the optimal power index (0.33 for physical gloss in the common prediction model, independent of the observation angle), we found that human gloss perception may be related to brightness perception.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2022-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88176708","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 : 2022-09-19DOI: 10.1177/14771535221122937
Arthur A. Webb, IP Terenetskaya, M. Holick, A. van Dijk, Rl L. McKenzie, R. Lucas, A. Young, PA Philipsen, F. D. de Gruijl
In 2006, CIE published a technical report on an action spectrum for the production of previtamin D3 in human skin. CIE procedure is to publish guidelines (e.g., an action spectrum) and let the community test them before moving to define a standard. The CIE previtamin D3 action spectrum has been in use for 15 years, and challenged on several occasions; a number of alternative action spectra have been suggested. To date (2021) no alternative action spectrum has shown clear advantages over the CIE version when tested against experimental outcomes. Thus, the CIE action spectrum remains widely used, but not fully accepted as best representing the photobiology in human skin leading to synthesis of vitamin D. We report on a CIE workshop designed to address the challenges to the CIE action spectrum, and explore alternative action spectra. The workshop concluded that the CIE action spectrum probably requires amendment, with several candidates for consideration in determining any changes. However, until there is a clear alternative, the CIE action spectrum should remain in use whilst ensuring full spectral information about sources of ultraviolet radiation. Thus, results are comparable between studies and can be recalculated to an updated action spectrum if necessary.
{"title":"Previtamin D action spectrum: Challenging CIE towards a standard","authors":"Arthur A. Webb, IP Terenetskaya, M. Holick, A. van Dijk, Rl L. McKenzie, R. Lucas, A. Young, PA Philipsen, F. D. de Gruijl","doi":"10.1177/14771535221122937","DOIUrl":"https://doi.org/10.1177/14771535221122937","url":null,"abstract":"In 2006, CIE published a technical report on an action spectrum for the production of previtamin D3 in human skin. CIE procedure is to publish guidelines (e.g., an action spectrum) and let the community test them before moving to define a standard. The CIE previtamin D3 action spectrum has been in use for 15 years, and challenged on several occasions; a number of alternative action spectra have been suggested. To date (2021) no alternative action spectrum has shown clear advantages over the CIE version when tested against experimental outcomes. Thus, the CIE action spectrum remains widely used, but not fully accepted as best representing the photobiology in human skin leading to synthesis of vitamin D. We report on a CIE workshop designed to address the challenges to the CIE action spectrum, and explore alternative action spectra. The workshop concluded that the CIE action spectrum probably requires amendment, with several candidates for consideration in determining any changes. However, until there is a clear alternative, the CIE action spectrum should remain in use whilst ensuring full spectral information about sources of ultraviolet radiation. Thus, results are comparable between studies and can be recalculated to an updated action spectrum if necessary.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83528945","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 : 2022-09-13DOI: 10.1177/14771535221111652
D. Baxter, D. Durmus, M. Royer
Multi-primary tunable LED lighting systems can generate a vast number of spectral outputs, with the exact number depending on the resolution of the control signal and number of LED primaries. Computing all combinations to identify optimal spectral power distributions (SPDs) with a specified chromaticity would require a tremendous amount of time and computational power. Here, an enumeration reduction (ER) algorithm is described to reduce the computation time by defining a bounding pyramid in the three-dimensional tristimulus space that maps to the circumscribed square of the target region in the chromaticity diagram. This method enables computing only the necessary amount of tristimulus values (and resulting chromaticity coordinates) for SPDs that fall into a user-defined target chromaticity area, reducing computation time by avoiding the need to generate each combination and calculate its chromaticity coordinates. The results show that the proposed ER algorithm can greatly reduce the time – up to 922 times in a series of tests – to determine a set of metamers compared to a full enumeration computation.
{"title":"Enumeration reduction algorithm for the characterization of multi-primary LED systems","authors":"D. Baxter, D. Durmus, M. Royer","doi":"10.1177/14771535221111652","DOIUrl":"https://doi.org/10.1177/14771535221111652","url":null,"abstract":"Multi-primary tunable LED lighting systems can generate a vast number of spectral outputs, with the exact number depending on the resolution of the control signal and number of LED primaries. Computing all combinations to identify optimal spectral power distributions (SPDs) with a specified chromaticity would require a tremendous amount of time and computational power. Here, an enumeration reduction (ER) algorithm is described to reduce the computation time by defining a bounding pyramid in the three-dimensional tristimulus space that maps to the circumscribed square of the target region in the chromaticity diagram. This method enables computing only the necessary amount of tristimulus values (and resulting chromaticity coordinates) for SPDs that fall into a user-defined target chromaticity area, reducing computation time by avoiding the need to generate each combination and calculate its chromaticity coordinates. The results show that the proposed ER algorithm can greatly reduce the time – up to 922 times in a series of tests – to determine a set of metamers compared to a full enumeration computation.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2022-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79270348","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 : 2022-09-10DOI: 10.1177/14771535221123237
KI Fostervold, DE Eilertsen
The discovery of intrinsically photosensitive retinal ganglion cells in the eye and their interaction with melatonin has shown that light has significant effects beyond vision. The present study compared the effect of an integrative lighting system, providing low-intensity melanopic illuminance with the effect of an ordinary, qualitatively equivalent, electric lighting system. The study utilised a 2 × 7 randomised mixed experimental design. The sample consisted of 13 women and 11 men. Salivary melatonin secretion and subjectively perceived sleepiness in the evening were measured every half hour during 3 hours of light exposure. The chronobiologic typology (stability and amplitude) and trait-like negative and positive affect were measured once and analysed as covariates. The results showed a general increasing linear effect for both melatonin and sleepiness. A significant nonlinear effect of time was present in the group exposed to integrative lighting, indicating delayed melatonin secretion. The findings were stable across all levels of the examined covariates. These results confirm that the integrative lighting system produces effects beyond vision under otherwise ordinary lighting conditions. Furthermore, the results corroborate research suggesting that melatonin secretion and sleepiness may not be directly linked. The integrative lighting system provides new opportunities to develop indoor electric lighting resembling daylight.
{"title":"Implementing integrative lighting in conventional office luminaires: Effects on melatonin secretion and sleepiness","authors":"KI Fostervold, DE Eilertsen","doi":"10.1177/14771535221123237","DOIUrl":"https://doi.org/10.1177/14771535221123237","url":null,"abstract":"The discovery of intrinsically photosensitive retinal ganglion cells in the eye and their interaction with melatonin has shown that light has significant effects beyond vision. The present study compared the effect of an integrative lighting system, providing low-intensity melanopic illuminance with the effect of an ordinary, qualitatively equivalent, electric lighting system. The study utilised a 2 × 7 randomised mixed experimental design. The sample consisted of 13 women and 11 men. Salivary melatonin secretion and subjectively perceived sleepiness in the evening were measured every half hour during 3 hours of light exposure. The chronobiologic typology (stability and amplitude) and trait-like negative and positive affect were measured once and analysed as covariates. The results showed a general increasing linear effect for both melatonin and sleepiness. A significant nonlinear effect of time was present in the group exposed to integrative lighting, indicating delayed melatonin secretion. The findings were stable across all levels of the examined covariates. These results confirm that the integrative lighting system produces effects beyond vision under otherwise ordinary lighting conditions. Furthermore, the results corroborate research suggesting that melatonin secretion and sleepiness may not be directly linked. The integrative lighting system provides new opportunities to develop indoor electric lighting resembling daylight.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2022-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77981688","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 : 2022-09-02DOI: 10.1177/14771535211061044
C. Cuttle
The author has previously proposed a novel spreadsheet-based lighting design objectives procedure (LiDOs) that enables practitioners to reconcile interacting LiDOs relating to the spatial distribution of illumination within a space, and this procedure has been successfully adopted by several lighting design practices. This paper proposes that the procedure is developed into an extended computer-based lighting design tool (LiDOs2) that includes LiDOs relating to spectral and temporal illumination distributions, as well as spatial distribution. This would enable regulators to specify limiting values for basic indoor lighting objectives such as perceived adequacy of illumination while at the same time guiding practitioners to incorporate LiDOs that address characteristics of lighting chosen to suit specific applications. The LiDOs2 procedure would be capable of generating holistic lighting performance specifications that would enable practitioners to conduct informed searches for light sources and luminaires, and to determine layouts and control circuits with confidence that the specified combination of LiDOs would be achieved.
{"title":"Extending the lighting design objectives procedure for holistic lighting solutions","authors":"C. Cuttle","doi":"10.1177/14771535211061044","DOIUrl":"https://doi.org/10.1177/14771535211061044","url":null,"abstract":"The author has previously proposed a novel spreadsheet-based lighting design objectives procedure (LiDOs) that enables practitioners to reconcile interacting LiDOs relating to the spatial distribution of illumination within a space, and this procedure has been successfully adopted by several lighting design practices. This paper proposes that the procedure is developed into an extended computer-based lighting design tool (LiDOs2) that includes LiDOs relating to spectral and temporal illumination distributions, as well as spatial distribution. This would enable regulators to specify limiting values for basic indoor lighting objectives such as perceived adequacy of illumination while at the same time guiding practitioners to incorporate LiDOs that address characteristics of lighting chosen to suit specific applications. The LiDOs2 procedure would be capable of generating holistic lighting performance specifications that would enable practitioners to conduct informed searches for light sources and luminaires, and to determine layouts and control circuits with confidence that the specified combination of LiDOs would be achieved.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84571515","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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