Lighting Research & Technology最新文献

{"title":"Evaluation of sky spectra and sky models in daylighting simulations","authors":"M. Inanici, Abboushi, MS SSafranek","doi":"10.1177/14771535221103400","DOIUrl":"https://doi.org/10.1177/14771535221103400","url":null,"abstract":"Sky models in daylight simulations represent the luminance variation across the sky-dome for different locations, dates, times and weather conditions, but skies are typically modelled as colourless. Recent studies explore techniques for incorporating the spectral content of daylighting in simulations. This paper provides an evaluation of the existing spectral sky models in lighting simulation software. The comparisons are made between the available mathematical sky models and naturally occurring skies that were recorded using high dynamic range photography and spectrophotometric measurements. The results show that recently developed sky models present progress compared to colourless sky models, but further research is needed to accurately simulate daylight spectra.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"66 1","pages":"502 - 529"},"PeriodicalIF":2.5,"publicationDate":"2022-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77966929","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}

{"title":"Visibility of the phantom array effect at different LED colour temperatures under high-frequency temporal light modulation","authors":"HR Kang, J. Kim, Sw Park, C-S Lee, H. Pak","doi":"10.1177/14771535221101558","DOIUrl":"https://doi.org/10.1177/14771535221101558","url":null,"abstract":"LEDs are widely used for both general and automotive lighting since their brightness can be easily regulated by controlling their on/off time using methods such as pulse width modulation (PWM). However, lighting control using PWM can cause temporal light artefacts, such as the phantom array effect, which affect human visual perception. In this study, we determined the influence of different colour temperatures on the visibility of the phantom array effect using five LEDs with different spectral distributions (red, green, blue, warm white and cool white) and frequencies of temporal modulation ranging from 1 kHz to 11 kHz. The threshold of the warm white LED was between that of the green and red LEDs, and threshold of the cool white LED was between that of the red and blue LEDs. The experimental results revealed a difference in the threshold frequency of the visibility of the phantom array effect, in accordance with the spectral distribution and the colour temperature of the light source.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"40 1","pages":"36 - 46"},"PeriodicalIF":2.5,"publicationDate":"2022-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76749731","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}

{"title":"Lighting measurement with a 360° panoramic camera: Part 2 – Applications","authors":"H. Li, H. Cai","doi":"10.1177/14771535221101556","DOIUrl":"https://doi.org/10.1177/14771535221101556","url":null,"abstract":"This study developed a 360° field of view (FOV) lighting measurement method with the aid of the Ricoh Theta Z1 panoramic camera. As versatile lighting information from all viewing directions within 360° FOV can be retrieved from a single 360° high dynamic range image, this new method improves the lighting measurement efficiency. Potential unique applications are reported in the present paper as Part 2 of this study. Corresponding lighting information covers a 360° luminance map, a 360° coefficient of variation map of luminance (CVL), a 360° luminance contrast (C1) map or ratio (Cr1) map between any interested target located at the viewing direction and its near background, a 360° luminance contrast (C2) map or ratio (Cr2) map between the same target and the ambient environment and a 360° illuminance map and its single coefficient of variation of illuminance (CVE) value of all illuminances on the illuminance map. All lighting information is measured at the same point with 360° viewing directions to analyse the uniformity and continuity of the lighting environment. An angular distance weighted illuminance calibration is used to correct possible mismatched white balance of the front and rear camera lenses in a scenario with multiple light sources of dramatically different Correlated Colour Temperature (CCTs). All customized camera-control and data treatment programs, including MATLAB code and Python programs, are uploaded to the project GitHub site for online sharing.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"1 1","pages":"712 - 729"},"PeriodicalIF":2.5,"publicationDate":"2022-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82810012","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}

{"title":"Illuminance uniformity in obstructed LED surgical lighting","authors":"H. Zhou, R. Ding, J. Qin, Y. Pan, M. Wang","doi":"10.1177/14771535221104495","DOIUrl":"https://doi.org/10.1177/14771535221104495","url":null,"abstract":"Uniform illumination is key to surgery. According to the standard, the illuminance uniformity is measured with no obstruction, which cannot fully reflect the performance in the working environment. This study aimed to measure the illuminance uniformity with obstruction. Besides, the illuminance attenuation dispersion rate was introduced. The illuminance uniformity test was set up under the IEC Standard, and five different types of luminaires were measured. The appropriate sizes of the light spots were chosen first. Subsequently, the light sources with light field diameters d50 and d10 with or without obstacles were measured, and the illuminance attenuation dispersion rate was calculated. The experimental results showed that the d50/d10 ratio did not appear to be affected by obstructions. There appeared visible deformation of the light spot shape in some products. As we assumed, there were significant differences in the illuminance attenuation dispersion rate among these products. Although d50/d10 ratio did not seem to be affected by the obstructions, the shape of the light spot deformed. The illuminance attenuation dispersion rate may be a key parameter to judge the LED surgical lighting.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"33 1","pages":"819 - 828"},"PeriodicalIF":2.5,"publicationDate":"2022-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75804468","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}

{"title":"Pre-bedtime activities and light-emitting screen use in university students and their relationships with self-reported sleep duration and quality","authors":"LM Huiberts, AL Opperhuizen, L. Schlangen","doi":"10.1177/14771535221074725","DOIUrl":"https://doi.org/10.1177/14771535221074725","url":null,"abstract":"In a three-day field study among 61 university students, we collected data on self-reported light-emitting screen activities (watching TV/series and using social media) and other behaviours (physical activity and food intake) during the 2 hours before bedtime and examined interrelations with self-reported sleep duration and quality. Students spent on average 19 minutes on screens using social media and 29 minutes watching TV/series before going to bed. Linear mixed model analyses revealed that a 10-minute increase in pre-bedtime social media use was associated with a significant decrease in sleep duration of 7 minutes, while 10 extra minutes of watching TV/series tended to increase sleep duration by 3 minutes. Physical activity and food intake before bedtime, and total screen time in bed were not significantly related to sleep duration. Subjective sleep quality was not significantly correlated with any of the investigated pre-sleep activities. In line with previous research, these findings suggest that the influence of pre-bedtime light-emitting screen use on sleep duration might be (partly) attributable to differences in screen activities. Discriminating between various types of screen activities is important when researching and developing recommendations for pre-bedtime behavioural strategies that are supportive for sleep, (school) performance and health.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"59 1","pages":"595 - 608"},"PeriodicalIF":2.5,"publicationDate":"2022-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78727660","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}

{"title":"Editorial: Outside-in and inside-out","authors":"J. Mardaljevic","doi":"10.1177/14771535221106508","DOIUrl":"https://doi.org/10.1177/14771535221106508","url":null,"abstract":"","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"35 1","pages":"309 - 309"},"PeriodicalIF":2.5,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77564661","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}

{"title":"Opinion: How do we define ‘healthy’ lighting?","authors":"Tm Brown, KP Wright","doi":"10.1177/14771535221107759","DOIUrl":"https://doi.org/10.1177/14771535221107759","url":null,"abstract":"Increased awareness about how the light to which we are exposed throughout the day influences our health, performance and well-being has sparked interest in practical solutions to optimise lighting design and practice to promote and maintain human health. What has been lacking until now, however, is an agreed definition as to what an appropriate daily pattern of light exposure should entail to inform these goals. It has long been known that light is a key regulator of our internal circadian clock, hormone levels, sleep and other aspects of physiology and cognitive function (so-called non-visual responses to light). These adaptations evolved to allow us to tune cycles of rest, activity, energy intake and associated body functions to the availability of natural light. However, our patterns of light exposure are now increasingly at odds with the natural solar cycle. Hence our dimmer days (due to reduced exposure to daylight) and brighter nights (due to ready access to electric light sources) can disrupt the normal functioning of these biological control mechanisms and contribute to acute and longer-term impacts on health and performance. The obvious solution is to make days brighter and evenings/nights dimmer, but how bright or dim? This has proved a particularly challenging problem because it does not just require agreeing a set of numbers but also identifying an appropriate way of measuring ‘brightness’ in the context of the light-sensing machinery that regulates such responses. Significant progress here became possible due to a new international standard for metrology (CIE S 026/E:2018) based around the properties of intrinsically photosensitive retinal ganglion cells (ipRGCs) known to mediate non-visual responses. The ipRGCs possess their own photopigment, melanopsin, which is maximally sensitive in a part of the spectrum (~490 nm in vivo) distinct from the cone photoreceptors whose properties underlie established photometric units. Since ipRGCs can also convey signals from rods and cones, however, there has been uncertainty as to the relative contribution of melanopsin versus these other signals. Accordingly, the new standard has formalised approaches for quantifying light separately for each of the photoreceptors that may contribute to ipRGC responses, and thereby has facilitated numerous retrospective evaluations of historical data and informed new hypothesis-driven investigations designed to address the existing uncertainty. These advances have now enabled the first expert scientific consensus, quantitative, recommendations for daytime, evening and night-time light exposure to best support physiology, sleep and wakefulness.1 The recommendations derive from an international group of leading specialists in the non-visual effects of light and associated metrology, informed by detailed evaluation of laboratory data and corroborating field studies which reveal melanopsin-weighted light exposure provides a reliable model of the sensitivity of prac","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"1 1","pages":"310 - 310"},"PeriodicalIF":2.5,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82596578","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}

{"title":"The law of reciprocity holds (more or less) for circadian-effective lighting","authors":"M. Rea","doi":"10.1177/14771535211061871","DOIUrl":"https://doi.org/10.1177/14771535211061871","url":null,"abstract":"Delivering effective lighting in buildings to support circadian entrainment of the occupants is of growing interest and importance to lighting specifiers. Circadian-effective lighting is not simply about how much light to provide; it also depends upon how long that light is provided. Recent research suggests that the amount of light and the duration of light exposure are reciprocally related for entrainment in the morning hours (i.e. 08:00–12:00). This opens up a number of design options heretofore unaddressed by lighting specifiers.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"35 1","pages":"748 - 760"},"PeriodicalIF":2.5,"publicationDate":"2022-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74145823","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}

{"title":"Opinion: Supporting PhD students","authors":"S. Fotios","doi":"10.1177/14771535221102479","DOIUrl":"https://doi.org/10.1177/14771535221102479","url":null,"abstract":"","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"63 1","pages":"198 - 198"},"PeriodicalIF":2.5,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76135780","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}

{"title":"Editorial: Assumptions are what we do not know we are making","authors":"P. Thorns","doi":"10.1177/14771535221097244","DOIUrl":"https://doi.org/10.1177/14771535221097244","url":null,"abstract":"","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"42 1","pages":"197 - 197"},"PeriodicalIF":2.5,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80674890","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}