Artificial Light Environment Research Articles

Optimisation of light environment in architectural space based on multi strategy collaboration – A case study of a manual drawing classroom

From the perspective of dynamic lighting throughout the year, reflector and louvre are proposed to add to the south-facing window. The optimal parameter is 2.0 m height and 1.0 m width reflector and a louvre angle of 75°. However, when further analysing the indoor illumination and uniformity, the classroom still had high or low illumination during certain periods solely relying on natural lighting, indicating that a single strategy alone cannot meet the overall lighting environment comfort needs of the space. The study suggests that different lighting environments should be used in different seasons, periods and areas of the classroom. The proportion of natural light, combined light and artificial light environments should be 30%, 45% and 25%, respectively. At the same time, considering the transformation and optimisation of the lamps, the improvement measures for windows facing other directions in the classroom is recommended, the lamps be symmetrically distributed in the horizontal direction, with a hanging height of 1.9 m in the vertical direction, which is 0.4 m higher than the original. The lighting power is 34 W and 26 W, and corresponding optimisation strategies for the intelligent control system are proposed.

신분증 OCR 인식 확률을 높일 수 있는 인공조명환경 연구

While the number of uses for ID(Identification) OCR(Optical Character Recognition) is increasing and the scope of its use is increasing, it has limitations in increasing the probability due to the problem of not being able to controlexternal conditions. The feedback currently being provided is not scientific, so it is unable to provide appropriate guidance to users. This study created a formula to avoid veiling reflection, which is the main cause of poor OCR, and allowed the angle of lighting to be adjusted according to the distance between the ID card and the camera. In addition, the BRDF(Bidirectional Reflectance Distribution Function) of the ID card was measured and simulated, and the point where the color luminance contrast was greatest was presented at an angle of 36 degrees between the light and the ID card, and this was verified in an actual situation. Through this, points where OCR can be good in an artificial lighting environment were presented in a scientific way, and machine learning was additionally conducted to provide a way for users to conveniently find places with a high OCR probability.

Effect of Light Quality on the Growth and Mechanical Property of Tomato Grafted Seedlings

Seedlin g quality is directly related to the success rate of automatic grafting. To select the suitable light quality for cultivating mechanically grafted tomato seedlings, the effects of different LED light qualities on the morphological parameters and mechanical properties of tomato seedlings were measured in an artificial light environment in a plant factory. Combination of red (R) and blue (B) LEDs as follows: R: B=100:0 (RLT), R: B=75:25(RBI), R: B=50:50(RBII), R: B=25:75(RBIII), R: B=0:100(BLT). The results showed that Red light is beneficial for the elongation of the hypocotyl of seedlings, Blue light is beneficial for the accumulation of dry matter in seedlings and monochromatic red light can reduce the seedling index. The effect of light quality on rootstocks and scions is different. Increasing the proportion of blue light is beneficial for increasing the stem diameter of scions, but it is not significant for the stem diameter of rootstocks. On the 25th to 30th day, the growth rate of stem diameter is the fastest. Based on morphological characteristics, the suitable light quality for rootstocks is RBI and RBII, and scions are RBII and RBIII. The mechanical properties of rootstocks and scions under different light-quality treatments were measured, and the results showed that the mechanical properties of scions were generally better than those of rootstocks. The rootstock has a significantly better bending strength than the scion, while the scion has a significantly better radial and axial compression force than the rootstock. Considering the automatic grafting process and mechanical characteristics, BLT and RBII were selected as the suitable light quality for rootstocks and scions. Based on the influence of comprehensive light quality on morphological and mechanical characteristics, the suitable light quality for cultivating mechanically grafted tomato seedlings is RBII.

Visually-shaped comfort of perceiving the architectural environment in conditions of artificial lighting (using the example of Chelyabinsk)

The study, conducted at the facilities of Chelyabinsk, aims to identify the essence of the comfort visually-shaped perception of the artificial architectural and light environment. This is achieved by an integrated approach, which involves the analysis of scientific and information resources, including regulatory and legal documents, field observations and surveys, graphical analysis of architectural and light environmental fragments under artificial lighting. An analysis of the regulatory framework on the lighting of architectural objects and urban space demonstrated the technical regulations of this sphere clearly articulating the visual comfort concept and its parameters only in relation to the interior space and the road transport system. The study clarified the concept and conditions of creating a shaping aspect in the visual perception of the urban artificial architectural and light environment. Mostly in terms of comfort for this process, the Chelyabinsk areas of the architectural and light environment in artificial lighting conditions were studied. Based on the results of the study, it can be concluded that the process of forming an artificial architectural and light environment of the city should be based on a visuallyshaped comfort, proceeding in a certain sequence and associated with the emergence of new factors of innovative urban environmental development. The relationship between the visually-shaped comfort of perceiving the artificial architectural and light environment, as well as the basics of the functional safety of subjects at the nodal points of the city were established. According to the experience of a typical domestic metropolis of Chelyabinsk, theoretical and research materials, presented in the article, can serve as the basis for the further interdisciplinary development of a visually comfortable and safe artificial architectural and light environment of cities.

ОРГАНИЗАЦИЯ СИСТЕМЫ УПРАВЛЕНИЯ ОФИСНЫМ ОСВЕЩЕНИЕМ С ВОЗМОЖНОСТЬЮ ТОЧЕЧНОЙ НАСТРОЙКИ

This article describes a specific approach to organizing the artificial light environment of an office space with a common space. The main criteria of modern lighting systems are given, which must be taken into account when designing. It is proposed to create an energy-efficient system with great functionality to integrate a lighting control module into the existing system, which includes LED lamps with built-in microcontrollers. To control the level of illumination and the color spectrum emitted by the LED lighting device in real time, it is proposed to use a portable small-sized sensor. The system for monitoring and controlling lighting parameters is built using Wi-Fi wireless data transmission technology. The control system will make it possible to carry out point individual adjustment, taking into account the specified operating parameters and user requirements.

The benefit of Daylight-Simulcasted Dynamic Lighting: An experiment isolating simultaneousness from dynamicity

Most people today stay in a constant artificial lighting environment for a long time. Lack of sufficient daylight exposure may lead to circadian, sleep or mental problem. Dynamic lighting is an effective countermeasure in consideration of its dynamicity. However, besides its changeability, whether the daylight simultaneousness of dynamic lighting has a beneficial effect is unclear. A lab-based study was carried out to explore the effect of Daylight-Simulcasted Dynamic Lighting (DSDL), which simulates the simultaneous information of daylight conveyed by its variation. A reversed pattern of DSDL (Re-DSDL) was also introduced as one of the test conditions for comparison. The within-subject experiment was performed by 24 participants in four conditions: two dynamic lighting patterns (DSDL and Re-DSDL) in two periods (dawn and dusk). The dependent variables were psychological states, physiological indicators and cognitive performance. The results showed that DSDL brought greater benefit to the psychological state than Re-DSDL in general. During dawn, participants experienced less anger and depression in DSDL than in Re-DSDL; during dusk, participants experienced less anger and vigour in DSDL than in Re-DSDL. DSDL also had a significant effect on some of the physical indicators compared with Re-DSDL, but no effect on cognitive performance.

Deciphering transcriptomic signatures explaining the phenotypic plasticity of nonheading lettuce genotypes under artificial light conditions.

Elucidating the mechanisms and pathways involved in genotype-environment (G×E) interactions and phenotypic plasticity is critical for improving plant growth. Controlled environment agricultural systems allow growers to modulate the environment for particular genotypes. In this study, we evaluated the effects of interactions among 14 genotypes and four artificial light environments on leaf lettuce phenotypes and dissected the underlying molecular mechanism via transcriptome-based modeling. Variations in morphological traits and phytochemical concentrations in response to artificial light treatments revealed significant G×E interactions. The appropriate genotype and artificial light combinations for maximizing phenotypic expression were determined on the basis of a joint regression analysis and the additive main effect and multiplicative interaction model for these G×E interactions. Transcriptome-based regression modeling explained approximately 50%-90% of the G×E variations. Further analyzes indicated Red Lettuce Leaves 4 (RLL4) regulates UV-B and blue light signaling through the effects of the HY5-MBW pathway on flavonoid biosynthesis and contributes to natural variations in the light-responsive plasticity of lettuce traits. Our study represents an important step toward elucidating the phenotypic variations due to G×E interactions in nonheading lettuce under artificial light conditions.

The perceptual variation of artificial light environment among college students due to the group defect of retinal light sensitivity

College students have similar visual work intensity and environment, resulting in idiosyncratic light environment perception. This study investigated the retinal light sensitivity characteristics of the college student group, and the relationship between retinal light sensitivity of different eccentricity ranges on visual perceptual performance in three typical behavioral modes of classrooms. The group characteristics of low mean light sensitivity (MS) and high pattern standard deviation (PSD) were obtained. 57.4% MS of them was lower than the normal threshold of the whole visual field. Moreover, the degree and irregularity of light sensitivity defect gradually increased from the center to the periphery. Light sensitivity indicators have significant effects on visual perceptual performance under typical classroom artificial light condition. Regression analysis was used to screen the “effective visual field indicators” and “optimal visual field indicators” for each visual perceptual performance. It was found that the visual perceptual performance of the desktop, blackboard, and changing-over modes relied primarily on the central, full-field, and peripheral visual fields, respectively. Further, the influence mechanism models and weight relationships between optimal indicators and visual perceptual performance were developed. Potential public visual health problems were quantified, leading to theoretical guide for classroom artificial lighting design oriented to visual perception.

Natural vs. Artificial Light: A Study on the Influence of Light Source on Chlorophyll Content and Photosynthetic Rates on Indoor Plants

Indoor landscaping is an environmentally friendly approach that enriches the environment and fosters productivity and comfort for occupants. The practice of incorporating plants into interior spaces requires meticulous care to ensure healthy growth and prolong the benefits of interior greening. This study explores the impact of natural and artificial light, represented by fluorescent lighting on the growth and physiological responses of Codiaeum variegatum and Ardisia japonica. A natural light chamber and an artificial light chamber of identical dimensions were constructed to compare the plants’ physiological responses under consistent temperature, humidity, and illuminance conditions. The results indicate that Codiaeum variegatum and Ardisia japonica exhibited higher chlorophyll content and photosynthetic rates under natural light conditions compared to fluorescent lighting. Furthermore, the study found that natural light offers a rich spectral distribution across various wavelengths, providing an advantage for plant growth. Although direct comparisons between natural and artificial light environments are inherently challenging due to the distinct characteristics of each light source, the study emphasizes the importance of considering the rich spectral distribution of natural light when designing artificial lighting systems for optimal plant growth. In conclusion, understanding the effects of natural and artificial light on indoor plants is crucial to supporting plant growth and creating more effective indoor gardening solutions. Although direct comparisons between natural and artificial light environments are inherently challenging due to the distinct characteristics of each light source, natural light provides a more advantageous environment for growth compared to fluorescent lighting, with Codiaeum variegatum and Ardisia japonica both exhibiting a higher chlorophyll content and photosynthetic rate under natural light conditions.

Associations between psychological responses under artificial light environment and sleep activity

Light helps mankind synchronize the circadian rhythm, necessitating the need to create a luminous environment in a bedroom. Many studies have focused on the effect of bedroom lighting regulation on sleep. However, there was a lack of research on how psychology responses are connected to sleep in residential bedroom. Thus, this chamber-based study explored mood differences among three correlated color temperatures (CCT; 2700 K, 4100 K, 5500 K). Additionally, the study analyzed the correlation of pre- and post-sleep psychological states with sleep quality. The results showed that suitable artificial lights (CCT at 2700K) in a bedroom before and after sleep under different conditions would provide the relaxation for subjects. Moreover, SOL, SWS, and SE were significantly different across different CCTs. According to the correlation and regression analysis, there were four groups of Pearson significantly correlated variables with coefficients of determination ranging from 0.34 to 0.70. Among them, 67% of the variation in SOL could be explained by the degree of pre sleep relaxation and pleasure. Furthermore, abundant and healthy sleep might perpetuate the mood generated by artificial lights. Finally, the roles of psychological states and sleep physiological responses should be considered while creating comfortable lighting conditions in bedrooms.

Proper use of light environments for mitigating the effects of COVID-19 and other prospective public health emergency lockdowns on sleep quality and fatigue in adolescents

Coronavirus disease 2019 (COVID-19) remains a public health emergency of international concern, and some countries still implement strict regional lockdowns. Further, the upcoming 2023 Asian Games and World University Games will implement a closed-loop management system. Quarantine can harm mental and physical health, to which adolescents are more vulnerable compared with adults. Previous studies indicated that light can affect our psychology and physiology, and adolescents were exposed to the artificial light environment in the evening during the lockdown. Thus, this study aimed to establish and assess appropriate residential light environments to mitigate the effects of lockdowns on sleep quality and fatigue in adolescents. The participants were 66 adolescents (12.15 ± 2.45 years of age) in a closed-loop management environment, who participated in a 28-day (7-day baseline, 21-day light intervention) randomized controlled trial of a light-emitting diode (LED) light intervention. The adolescents were exposed to different correlated color temperature (CCT) LED light environments (2000 K or 8000 K) for 1 h each evening. The results for self-reported daily sleep quality indicated that the low CCT LED light environment significantly improved sleep quality (p < 0.05), and the blood test results for serum urea and hemoglobin indicated that this environment also significantly reduced fatigue (p < 0.05) and moderately increased performance, compared to the high CCT LED light environment. These findings can serve as a springboard for further research that aims to develop interventions to reduce the effects of public health emergency lockdowns on mental and physical health in adolescents, and provide a reference for participants in the upcoming Asian Games and World University Games.

DeflickerCycleGAN: learning to detect and remove flickers in a single image.

Eliminating the flickers in digital images captured by rolling shutter cameras is a fundamental and important task in computer vision applications. The flickering effect in a single image stems from the mechanism of asynchronous exposure of rolling shutters employed by cameras equipped with CMOS sensors. In an artificial lighting environment, the light intensity captured at different time intervals varies due to the fluctuation of the AC-powered grid, ultimately leading to the flickering artifact in the image. Up to date, there are few studies related to single image deflickering. Further, it is even more challenging to remove flickers without a priori information, e.g., camera parameters or paired images. To address these challenges, we propose an unsupervised framework termed DeflickerCycleGAN, which is trained on unpaired images for end-to-end single image deflickering. Besides the cycle-consistency loss to maintain the similarity of image contents, we meticulously design another two novel loss functions, i.e., gradient loss and flicker loss, to reduce the risk of edge blurring and color distortion. Moreover, we provide a strategy to determine whether an image contains flickers or not without extra training, which leverages an ensemble methodology based on the output of two previously trained markovian discriminators. Extensive experiments on both synthetic and real datasets show that our proposed DeflickerCycleGAN not only achieves excellent performance on flicker removal in a single image but also shows high accuracy and competitive generalization ability on flicker detection, compared to that of a well-trained classifier based on ResNet50.

Investigation of mechanisms underlying a light approaching behavior in a house gecko by comparative and learning experiments

Nocturnal predators of many taxa are known to come to artificial light at night for foraging on clumped food resources. Both innate and acquired light preferences seem to be possible mechanisms of light approaching behavior although empirical tests are lacking in most nocturnal predators. Here, using a Japanese gecko Gekko japonicus, we investigated whether geckos have a light preference and how foraging experiences under the light reinforce light approaching tendency. In a comparative experiment, there was no difference in light approaching behavior between urban and suburban geckos irrespective of their original light habitats. In an associative learning experiment, geckos did not significantly change light approaching behavior even after repeated opportunities to forage crickets near a lamp in the laboratory setting. These results imply that light approaching behavior of Japanese geckos may not be easily reinforced by foraging experiences under the light. Although we often witness geckos coming to artificial light at night, our findings may not suggest their light preference. Geckos may approach the light-up foraging spot based on other cues relating to the artificial light environment.

Description of Light Environment in Broiler Breeder Houses with Different Light Sources-And How It Differs from Natural Forest Light.

Light is a key factor in poultry production; however, there is still a lack of knowledge as to describing the light quality, how to measure the light environment as perceived by birds, and how artificial light compares with the light in the natural forest habitats of their wild ancestors. The aim of this study was to describe the light environment in broiler breeder houses with three different light sources, using two different methods of light assessment. We also aimed to compare an artificial light environment with the light in a range of relevant natural forest habitats. A total of 9 commercial broiler breeder houses with one of three different light sources-Lumilux 830 CFL (n = 3), Biolux 965 CFL (n = 3) or LED Evolys with UVA (n = 3) were visited. Assessments of the light environment in the breeder houses were conducted using both a spectrometer and the environmental light field (ELF) method. ELF measurements from three forest types in south India (Kerala) were also included. We found that most aspects of the light environment were similar between the nine breeder houses and were not dependent on the type of light sources. The only clear difference related to the light source was the spectral balance, wherein 830 CFL had the most red-dominated light, 965 CFL had the most blue-dominated light and Evolys was intermediate but with more UV than the latter two. Plumage color had minimal effect on the light environment. Both the spectrometer and the ELF method provided valuable information. The spectrometer gave detailed values about certain aspects of the light environment, while the ELF described the light more in line with human and avian visual perception. We also found that the light environment in the investigated broiler breeder houses differs dramatically in all measured aspects from the natural light habitats of wild junglefowl, suggesting improvement possibilities in artificial lighting systems.

Obtaining a light intensity regulation target value based on the tomato dry weight model

The subsequent plant growth is determined by tomato seedling quality which is affected by light intensity. The present study proposes a method for obtaining the regulatory target value by using the U-chord length curvature method based on the dry weight model-fitted curve characteristics to obtain the optimum light intensity at the seedling stage. Tomato seedlings were selected as the experimental material, and six photosynthetic photon flux densities (PPFDs) were set under completely artificial side lighting. Depending on the scattering trend, the tomato shoot dry weights (SDWs) were fitted by the polynomial, logarithmic, and half logistic function models after optimization of parameters by using the differential evolution algorithm (DE-HLFM). According to the curve variation characteristics, the discrete curvature values corresponding to the models calculated using the U-chord length curvature method were 335, 108, and 241.3 µmol·m−2·s−1, respectively. Physiological tomato growth indicators exhibited that L4 had the smallest root–shoot ratio and the highest level of seedling index and SDW significance. Moreover, L4 had the highest SDW per PPFD improvement efficiency. Thus, tomato seedlings under L4 exhibited the best quality and highest efficiency among those under the six PPFDs. DE-HLFM optimization was closest to the optimal PPFD L4 (243.17 ± 4.37 µmol·m−2·s−1), indicating that DE-HLFM is the most suitable model with a coefficient of determination (R2) of 0.99897 and root-mean-square error of 0.00554. Thus, the PPFD corresponding to the maximum curvature point of the appropriate model exhibited physiological and production regulation significance. In conclusion, based on the curve characteristics, the curve feature point obtained using the U-chord curvature method can be used as the control target value for the precise control of the artificial controllable light environment.

Costs and Limitations of Marine Synechococcus Blue-Green Chromatic Acclimation

Benefits and trade-offs of blue/green chromatic acclimation (CA4) have received limited study. We investigated the energetic costs associated with executing chromatic acclimation using a fluorescence-based calculation of light use efficiency. Using laboratory cultures and artificial light environments, we show that the delayed response to acclimation known to occur in marine Synechococcus acclimating strains (generalists) in green light do not reduce light use efficiency in green light, but that only one generalist, RCC307, with a much smaller range of acclimation, had higher light use efficiency than blue and green light specialist strains. Generalists with a wider acclimation range either had the same or &amp;gt;30% lower light use efficiencies in blue and green light environments. From this work, we propose that advantages from CA4 may not be geared at direct competition with other Synechococcus specialists with fixed pigment types, but may serve to expand the ecological range of Synechococcus in spectral competition with other genera. As all eight Synechococcus strains tested had higher light use efficiency in green light, regardless of a fixed or flexible light harvesting strategy, we add evidence to the suitability of the Synechococcus genus to greener ocean niches, whether stable, or variable.

Effect of the light and dark conditions on flower opening time between cultivated rice (Oryza sativa) and a near-isogenic early-morning flowering line.

Flower opening time (FOT) is affected by genetic and environmental factors, but little is known about the effect of light and dark conditions on FOT in cereal crops. FOT of an indica rice cultivar, IR64, and its near-isogenic line carrying a QTL for an early-morning flowering trait (IR64+qEMF3) were investigated in a natural-light and temperature-controlled small greenhouse by exposing either the panicle or stem or both plant organs to different light and dark conditions. FOT did not change in either genotype when panicles were exposed to light. A large difference in FOT was found between genotypes when panicles were exposed to dark conditions; no flower opening was observed in IR64, whereas flower opening was delayed but observed in IR64+qEMF3. These results suggest that the panicle is the organ that perceives light for flower opening in both genotypes, whereas the light requirement to reach flower opening was quite different between genotypes. Flower opening of IR64 occurred concomitantly with elongation of anther filament in the light after the dark treatment stopped, whereas approximately half of flowering of IR64+qEMF3 resulted in apparent cleistogamy even during dark treatment. An extended duration of the dark treatment until 1730H (30–50 min before sunset) made FOT of IR64 spikelets on the next day shifted to a time as early as that of IR64+qEMF3, with significant advancement of FOT compared to the control IR64 spikelets. Our results indicated that different flowering responses to light and dark conditions exist between IR64 and IR64+qEMF3. These findings provide clues for understanding the unique genetic controls of flowering in an EMF line in rice. This study also showed evidence that artificial light environments can shift the FOT of IR64 to that of IR64+qEMF3.

An orthogonal design of light factors to optimize growth, photosynthetic capability and metabolite accumulation of Anoectochilus roxburghii (Wall.) Lindl.

Light is one of the key environmental factors influencing plant physiology and biochemistry, and light intensity (I),red and blue photon flux ratio (S) and photoperiod (P) are important light factors affecting plant growth, photosynthetic capability and metabolite accumulation. Nevertheless, little is known regarding the optimal combination of the three light factors for plant artificial cultivation and the effect of combination on plant physiology. In this study, Anoectochilus roxburghii(Wall.) Lindl., which is an important Chinese medicinal plant, was cultivated and continuously investigated under artificial light environment that the three light factors (I, S, P) were designed according to L16(43)orthogonal array. The results showed that all the light factors significantly affected leaf area, stem diameter, plant length, dry weight, flavonoids and polysaccharides contents. Red and blue photon flux ratio and photoperiod significantly influenced pigment content, but light intensity did not significantly influence it. Chlorophyll fluorescence analysis showed that high light intensity not only could lead light stress, but also could promote photosynthetic capacity by combination with red and blue photon flux ratio and photoperiod. The improved protocols I2S2P2(I=60 μmolm−2s−1, S=2:1 and P=10 h) and I4S1P4(I=100 μmol m−2s−1, S=1:1 and P=14 h) were validated and demonstrated to be the optimal combinations for growth and total polysaccharides content (I2S2P2) and for flavonoids contents (I4S1P4) respectively. This study also demonstrated that orthogonal array design is an efficient way to establish improved protocols of light for artificial cultivation of A. roxburghii.

Physiological Effects of Artificial Light Environment on Rice in Ecological Landscape

Artificial light sources have been widely used in urban night lighting and country road lighting. Landscape lighting makes plants, buildings and various urban or rural structures covered with prosperous cloaks, and the transformation of light and shadow makes the landscape environment more beautiful. However, while creating a unique lighting landscape, the light source often neglects the influence of its light environment on the physiological morphology of plants. More often, it causes light pollution, chaotic light, and environmental damage. Therefore, this paper reviews the research on the effects of artificial light environment on rice physiological morphology as an example. The design of light source in the direction of ecological landscape should be more in line with the requirements of plant growth, and achieve “material-oriented”.

Site Fidelity of Gekko japonicus to Artificially Lit Environments

Several reptiles and amphibians frequently occur in environments exposed to artificial lights and appear to effectively hunt prey animals attracted to the light. Therefore, it would be beneficial for them to use such a habitat to survive in urban areas. In this paper, we examined site fidelity of a nocturnal gecko, Gekko japonicus, to a particular artificial light environment in the field. We observed short-term dependence on the same light environment by individual geckos for four to nine consecutive nights and also examined long-term site fidelity once every 10 days from March to November. The same individual frequently came to the particular light for several consecutive nights, but day and time of appearance varied among individuals. Over several months, 20% of marked individuals were repeatedly sighted at the same place although the number of their re-sightings was low (1–5 times). These results suggest that each G. japonicus may settle down in a certain artificially lit environment and use it repeatedly, but the dependence on lights not be so strong.