Lighting Design Research Articles

Spectral-level assessment of light pollution from urban façade lighting

Façade lighting makes cities brighter at night and causes ecological impacts, as more wavelengths associated with species spectral sensitivity are emitted in light spectra. To assess the resulting ground-level light pollution and explore ecological lighting strategies, this study collected hyperspectral data of 74 lighting facades in Shanghai, China and analyzed lighting features related to ecological impacts. Spectral-level assessment shows that multi-spectral lighting causes higher luminance, more variable colours, and stronger eco-impacts, e.g., on human circadian rhythms, human photopic vision and plant photosynthesis than uniform-colour lighting. High ecological impacts are associated with narrow spectra of saturated blue and red colours, and cannot be effectively reduced by luminance control. A colour gamut mapping strategy is thus proposed to reduce the eco-impacts through colour restriction. This study quantitatively assesses the light pollution from façade lighting and reveals the associations between different lighting indicators and ecological impacts. The colour gamut mapping strategy provides a trade-off between visual effects and eco-impacts, which helps to balance the needs of urban development and environment. The findings provide guidance to lighting manufacturers, designers and policy makers on eco-lighting design and its integration into sustainable lighting masterplans.

KONSTRUKSI LAMPU GANTUNG MENGGUNAKAN TABUNG, BOLA, TORUS, KERUCUT DENGAN KONSEP DEFORMASI, TRANSFORMASI DAN KURVA BEZIER

The purpose of this study is to obtain a hanging light design from a combination of several components using Maple. The results show that the construction procedure for the hanging light components can be carried out in three stages. First, determining some data for cylinder, sphere, torus, cone, and Bezier curve. Second, dividing the hanging light into several components, then creating a procedure for constructing each component using the concepts of deformation, transformation, and Bezier curve. Third, combining all components on the modeling axis and compiling a program using a computer.

Single-Wire Control and Fault Detection for Automotive Exterior Lighting Systems.

The design of exterior lighting is crucial for automotive manufacturers to ensure the visibility and safety of the driver. This article proposes a new strategy to control and diagnose one or more exterior lighting functions in electric vehicles by maximising the electrical faults that are detected and their transfer over a single-wire. The outcome is a decreased system cost and an additional method for vehicle lighting infrastructure control and diagnosis. Virtual simulation tools are used to explore the correlation between master-slave architecture and the effectiveness of the single-wire approach to comply with safety and regulatory demands. Safety-related and non-safety-related needs are explored to properly assess lighting functions, internal logic, and fault-case scenarios. Furthermore, assessing the viability of minimizing wire harness utilization while retaining the diagnostic capabilities for the controlled lighting sources, thereby simultaneously reducing the vehicle's overall weight. This approach aims to concurrently decrease the overall weight of the vehicle. This work has three main contributions: (1) the development of efficient and reliable lighting systems in electric vehicles, a critical factor for achieving optimal performance, ensuring customer satisfaction, meeting regulatory compliance, and enhancing cost-effectiveness in automotive lighting systems. (2) Framework for future development and implementation of lighting systems in electric vehicles. (3) Simulation of the hardware architecture associated with the system strategy to achieve the desired system strategy for effectively applying the single-wire approach.

Multi-frequency polarization and electro-optical modulator based on triple plasmon- induced transparency in monolayer graphene metamaterials

In this paper, a dynamically tunable triple plasmon-induced transparency (PIT) is numerically investigated in a simple monolayer graphene- patterned structure. The structure is composed of five graphene strips and a silicon substrate. Electric field distributions show that the triple PIT effect is originated from the strong destructive interference between three bright modes and one dark mode, coupled mode theory (CMT) is utilized to confirm the finite-difference-time-domain (FDTD) simulation. Results show the maximum figure of merit (FOM) and sensitivity can reach 15.88 and 0.91 THz/RIU. A on-to-off electro-optical modulator is realized by tuning the Fermi levels of the graphene, the modulation degrees of amplitude are 79.3 %, 87.1 %, 70.5 %, 79.2 %, and 84.3 %, corresponding to 2.35 terahertz (THz), 3.12THz, 3.58 THz, 3.91THz, and 4.31 THz, respectively. In addition, the effect of polarized angle on the transmission spectra was studied in detail. A multi-frequency polarization modulator can also be realized with modulation degrees of amplitude (MDA) of 77.6 %, 85.9 %, and 93.7 % at 2.09 THz, 2.82 THz, and 3.59 THz, respectively, and the corresponding polarization extinction ratio (PER) are 6.5 dB, 8.5 dB, and 12.1 dB, respectively. Therefore, the results of the paper are significant to the design of multi-frequency, terahertz sensors, slow light, and modulators.

Inverse Design of Light Manipulating Structural Phase Transition in Solids.

This Perspective focuses on recent advances in understanding ultrafast processes involved in photoinduced structural phase transitions and proposes a strategy for precise manipulation of such transitions. It has been demonstrated that photoexcited carriers occupying empty antibonding or bonding states generate atomic driving forces that lead to either stretching or shortening of associated bonds, which in turn induce collective and coherent motions of atoms and yield structural transitions. For instance, phase transitions in IrTe2 and VO2, and nonthermal melting in Si, can be explained by the occupation of specific local bonding or antibonding states during laser excitation. These cases reveal the electronic-orbital-selective nature of laser-induced structural transitions. Based on this understanding, we propose an inverse design protocol for achieving or preventing a target structural transition by controlling the related electron occupations with orbital-selective photoexcitation. Overall, this Perspective provides a comprehensive overview of recent advancements in dynamical structural control in solid materials.

Unsupervised Low-Light Image Enhancement via Virtual Diffraction Information in Frequency Domain

With the advent of deep learning, significant progress has been made in low-light image enhancement methods. However, deep learning requires enormous paired training data, which is challenging to capture in real-world scenarios. To address this limitation, this paper presents a novel unsupervised low-light image enhancement method, which first introduces the frequency-domain features of images in low-light image enhancement tasks. Our work is inspired by imagining a digital image as a spatially varying metaphoric “field of light”, then subjecting the influence of physical processes such as diffraction and coherent detection back onto the original image space via a frequency-domain to spatial-domain transformation (inverse Fourier transform). However, the mathematical model created by this physical process still requires complex manual tuning of the parameters for different scene conditions to achieve the best adjustment. Therefore, we proposed a dual-branch convolution network to estimate pixel-wise and high-order spatial interactions for dynamic range adjustment of the frequency feature of the given low-light image. Guided by the frequency feature from the “field of light” and parameter estimation networks, our method enables dynamic enhancement of low-light images. Extensive experiments have shown that our method performs well compared to state-of-the-art unsupervised methods, and its performance approximates the level of the state-of-the-art supervised methods qualitatively and quantitatively. At the same time, the light network structure design allows the proposed method to have extremely fast inference speed (near 150 FPS on an NVIDIA 3090 Ti GPU for an image of size 600×400×3). Furthermore, the potential benefits of our method to object detection in the dark are discussed.

Measurement and Curb of Light Pollution Risk Levels

Nowadays, light pollution has become a serious environmental problem. However, there are no clear indicators to assess the level of light pollution risk in a certain area. Firstly, we took 31 provinces and cities in China as the research object, and collected the data of seven indicators that affect the risk level of light pollution, then weighted them using Analytic Hierarchy Process (AHP). Secondly, we used the Topsis method for quantitative calculation, and classified the light pollution risk level into five levels: heavy light pollution (score>0.05), high light pollution (0.04<score<0.05), moderate light pollution (0.03<score<0.04), mild light pollution (0.02<score<0.03), and no light pollution (score<0.02). Thirdly, we linked the light pollution risk level to the Comprehensive Development Level Index (CDCI) of each province and city, and divided the cities into four categories according to the CDCI. Then we used analogy analysis to measure the risk level of light pollution in four land types: protected land(score<0.02), rural area (0.02<score<0.03), suburban area (0.03<score<0.04) and urban area (score>0.04). Fourthly, we propose three intervention strategies to combat light pollution: strengthen urban planning and management, better the ecological design of nightscape lighting and improve the material of glass curtain wall. Finally, we test its rationality and feasibility. Our model can analyze the light pollution risk level of other countries or even continents. This is conducive to the government's future planning and resource control of the region.

Light distribution technology of light-emitting-diode automotive lamps based onrippling pattern.

In this era of led-emitting-diode (LED) lighting, it is important to find a universal pattern structure for the LED automotive lamp optics. This paper starts with the secondary light distribution design method of a rippling pattern through the explanation and simulation analysis of its design principle and determines a 4 ' ' round signal lamp scheme with good performance. It then completes the proofing verification of this scheme, and the test results achieve the original design goal. Additionally, several examples of other lamp types with the rippling pattern are introduced, including a 4 ' ' round halo lamp and 7 ' ' transit lamp.

Degradation of ciprofloxacin by persulfate activated by Fe(III)-doped BiOCl composite photocatalyst.

Fe-BOC-X photocatalyst was successfully prepared by solvothermal method. The photocatalytic activity of Fe-BOC-X was determined by ciprofloxacin (CIP), a typical fluoroquinolone antibiotic. Under sunlight irradiation, all Fe-BOC-X showed better CIP removal performance than original BiOCl. In comparison, the photocatalyst with iron content of 50 wt% (Fe-BOC-3) has excellent structural stability and the best adsorption photodegradation efficiency. The removal rate of CIP (10mg/L) by Fe-BOC-3 (0.6g/L) reached 81.4% within 90min. At the same time, the effects of photocatalyst dosage, pH, persulfate, persulfate concentration, and combinations of different systems (PS, Fe-BOC-3, Vis/PS, Vis/Fe-BOC-3, Fe-BOC-3/PS, and Vis/Fe-BOC-3/PS) on the reaction were systematically discussed. In reactive species trapping experiments, electron spin resonance (ESR) signals revealed that the photogenerated holes (h+), hydroxyl radical (•OH), sulfate radical (•SO4-), and superoxide radical (•O2-) played an important role in CIP degradation; hydroxyl radicals (•OH) and sulfate radicals (•SO4-) play a major role. Various characterization methods have demonstrated that Fe-BOC-X has larger specific surface area and pore volume than original BiOCl. UV-vis DRS indicate that Fe-BOC-X has wider visible light absorption and faster photocarrier transfer and provides abundant surface oxygen absorption sites for effective molecular oxygen activation. Accordingly, a large number of active species were produced and participated in the photocatalytic process, thus effectively promoting the degradation of ciprofloxacin. Based on HPLC-MS analysis, two possible decomposition pathways of CIP were finally proposed. The main degradation pathways of CIP are mainly due to the high electron density of piperazine ring in CIP molecule, which is mainly attacked by various free radicals. The main reactions include piperazine ring opening, decarbonylation, decarboxylation, and fluorine substitution. This study can better open up a new way for the design of visible light driven photocatalyst and provide more ideas for the removal of CIP in water environment.

Τhe effect of artificial lighting on both biophilic and human-centric design

The indoor environmental quality is very significant as humans spend more than 90% in indoor space. Biophilic design of indoor spaces has become a popular approach in the design of indoor building spaces sector using green walls, especially in offices, leisure and hospitality facilities. So far there exist neither guidelines with the proper Spectral Power Distribution (SPD) except for agricultural applications or intensity levels of lighting nor the proper spectral indices to transform the photopic illuminance to a new type of photometric quantity for biophilic design. On the other hand, for human centric lighting the Equivalent Melatonin Illuminance is already introduced. The aim of paper is to define the appropriate lighting conditions, not only for humans, but also for interior plants. A new metric was introduced for the biophilic design named Equivalent Photosynthetic Illuminance. The new metric was examined for two human-centric lighting luminaires and compared with the corresponding human centric lighting metrics in order to create a lighting design guide for energy-sustainable, biophilic and human-centered lighting. The different SPDs highlighted the counterbalancing impact(s) of such luminaires, between biophilic and human-centered design. The differences concerning their impact on interior lighting design were identified with regards to energy consumption, meaning that the compliance of the lighting conditions to both humans and plants results to higher energy consumption. Depending on the SPD and luminous efficacy of artificial lighting, the additional power density for proper planning of biophilic design can vary from 23.5W/m2 to 52.4W/m2 in the areas in which are applied.

Influence of luminance and luminance longitudinal uniformity of tunnel lighting on drivers' comprehensive visual performance

The present study aimed to investigate the comprehensive influence of the average luminance Lav and luminance longitudinal uniformity U1 on the diver’s visual performance under the stage of driving in the tunnel’s interior zone during the experiment. Specifically, we collected reaction time, pupil area change rate, and blink frequency from 40 participants through the indoor visual performance experiments. The present study quantitatively characterized the mechanism of the antagonism between luminance intensity and difference, and established the Lav-U1 curve which succeeds in satisfying the safety threshold of the driver's comprehensive visual performance. The results show that the driver's visual performance deteriorated continuously as the test time increases. Increasing the luminance was beneficial for accelerating the reaction speed, but also caused greater stimulation of light and dark changes. The change ratio of reaction speed and the increased amplitude of perceived luminance increased exponentially with the increase of luminance, resulting in an antagonism effect. The visual performance decreased with the increase of average luminance under low uniformity levels, and increased with the increase of average luminance under high uniformity levels. Furthermore, we found that the luminance longitudinal uniformity should match up the luminance in the interior zone, instead of separation under the current specification. Based on our findings, we propose specific recommendations for the luminance longitudinal uniformity under different average luminance levels. For the interior zone of tunnels with an average luminance of 2.5, 4.5, and 6 cd/m2, the luminance longitudinal uniformity should be increased from 0.6 to 0.67, 0.72, and 0.75, respectively. Current findings demonstrate that the implementation of the proposed U1 standard in tunnel lighting design can significantly fasten drivers' reaction time, contribute to a decrease in traffic accidents, and thus improve the safety level of tunnel lighting design in the interior zone of tunnel. These results have significant implications for the design of tunnel lighting.

Tunnel lighting calculation model based on bidirectional reflectance distribution function: Considering the dynamic changes in light transmittance in road tunnels

The current tunnel lighting calculation method does not completely consider the dynamic change in light transmittance in a tunnel and reflection characteristics of the tunnel sidewall. Thus, the measured and calculated values of road surface illuminance present a considerable difference, which seriously affects the tunnel lighting design and quality evaluation. To overcome this limitation, in this study, in addition to theoretical analysis and measured experiments, the changing trend in light attenuation is analyzed and a light attenuation model is established. Next, a bidirectional reflectance distribution function that can accurately reflect the reflection characteristics of tunnel sidewall is combined with the light attenuation model and calculation steps based on optical theory to construct a tunnel lighting calculation model considering light transmittance (TLCM-LT). Finally, theoretical calculation and actual measurement verification are conducted via an experimental tunnel simulation, and the results obtained using TLCM-LT are compared with the values calculated based on the Commission Internationale de l'éclairage (CIE), Illuminating Engineering Society of North America (IESNA), and Industry Standards of the People’s Republic of China (JTG) specifications. The results show that the average relative error of the TLCM-LT in a smoke-free environment is 1.31 %. In the presence of smoke, the average relative error of the model fluctuates in the range of 2.19–6.8 % with the change in light transmittance in the tunnel, which is significantly lower than the errors obtained based on the CIE, IESNA, and JTG specifications. Compared with a cement sidewall, the average increase rates in road surface illuminance and illuminance uniformity of the highly diffuse reflective sidewall are 23.21 and 3.65 %, respectively.

Research on the Modeling of Series Lighting Products based on Natural Elements in Bionic Design

In modern lighting design, more and more designers use bionic design for product innovation. The article divides the bionic design into three dimensions: whole, part, and detail. On this basis, it proposes simplified bionic and structural redesign. Bionic and texture reorganization are three methods, and the feasibility of the three methods is confirmed through case studies. The simplified bionic method is applied to the actual series of lamps and lanterns design. Rhino and KeyShot are used for 3D modeling and rendering. The final design A series of lamps have been produced to confirm that the design method in the article is effective, and I hope it will be helpful to future lamp designers.

Energy and Economic Sustainable Illumination Design for a Gymnasium: A Case Study

Gymnasium lighting design is crucial to provide better visibility, improve overall mood and serve a good experience to the occupant. Conventional artificial lighting might serve these well, but it consumes a significant amount of energy. In this report, a sustainable lighting design for a gymnasium at Taylor’s University, Subang Jaya, Malaysia, is developed per the SIRIM 33:2019. The aims are to provide better energy-efficient and sustainable lighting design solutions while maintaining good visibility, overall mood, and meeting the required illumination level. The design is developed in a 3D lighting simulation software, the DIALux Evo 10. The proposed LED lighting design is compared with the existing high-pressure sodium high-bay lighting system. Criterion such as the illuminance level, glare rating index, colour rendering, energy performance and economic assessment are analysed. Result of the analysis shows that the proposed LED luminaires achieved of 68% potential energy consumption reduction, a payback period of 4.9 years and an annual life cost cycle of RM 1, 345.76, compared to the existing fluorescent luminaires’ annual life cost cycle of RM 3,570.29. This shows that LED luminaires have better energy performance, and improved cost saving while producing better illuminance level output. The outcome of this study can be considered for future gymnasium lighting design to achieve energy and economic sustainability.

Study on Evaluation of Night Lighting Design in Urban Green Space

In a fast-paced life, people spend more time at night. Thus, the quality of lighting at night is required in urban green areas where people do a lot of activities. The design of night lighting demands functionality and environmental friendliness. Therefore, we surveyed and analyzed visitors’ experience using a questionnaire survey for the landscape lighting design of the Xuzhou city’s green space. The results showed that visitors were not satisfied with the lighting color and brightness. The current lighting design in the urban green space needs an improvement with new design ideas and concepts.

Lighting Automation

Abstract: In most of the educational institutions, the significant amount of energy is spent for illuminating the classrooms and for switching the fans, computers and so on. Sometimes due to unnecessary consumption of energy the energy costs may rise. practices. In order to minimise the energy consumption or to avoid energy waste during unoccupied and daylight hours ,here more efficient equipment is designed for utilization of improved lighting design Here we have established a lighting control system in which the light circuits and fans in classroom remain Off in the absence of students and switches on in their presence. When student enter classroom , Infrared energy emitted from the person activates the IR sensor and the aurdino acts as power saving device according to relay operations. By using IR Sensor is detected the relays are triggered and the fan and lights are switched On. Measuring the brightness of the cl motion LDR Sensor for assroom and also a sensor is used for the measuring the temperature, if the temperature is above 25°C the fans will be turned ON.

High Pressure Light Scattering of Therapeutic Proteins To Probe Aggregation and Protein-Protein Interactions.

There is interest in the direct in situ measurement of protein aggregation and reversible protein-protein interactions at high pressure as a means to assess protein stability. This is currently limited by the availability of in-house analytical methods. High-pressure (HP) scattering instrumentation (using either neutrons, X-rays, or light sources) are relatively rare, due to extensive development hurdles and lack of standardization. This report focuses on design, operation, and application of a new HP light scattering apparatus based on commercially available equipment with a view to wider applications. HP static light scattering results were obtained for two monoclonal antibodies (MAbs) that exhibit different extents of unfolding and aggregation at these conditions. Aggregation that was observed during in situ pressure incubations varied by MAb and total ionic strength of solution. This was conducted in tandem with ex situ measurements on MAb solutions that were incubated under pressure, where monomer loss was measured with size exclusion chromatography. Pressure cycling was also used to assess the extent of pressure-induced reversible and irreversible aggregation. Finally, the ability of the HP light scattering apparatus to assess the influence of pressure on reversible protein-protein interactions in the canonical sense of second osmotic virial coefficients was assessed using lysozyme, a relatively well-characterized protein under hydrostatic pressure. The method offers a convenient and reproducible capability that complements current small angle neutron/X-ray instrumentation, providing measurements that can be used to optimize the planning and interpretation of scattering data from synchrotron or neutron research facilities. Our results address a growing demand to characterize protein aggregates and aggregation-prone partially unfolded intermediates.

Automatic detection of concrete cracks from images using Adam-SqueezeNet deep learning model

Cracks on concrete surface are typically clear warning signs of a potential threat to the integrity and serviceability of structure. The techniques based on image processing can effectively detect the cracks from images. These techniques, however, are generally susceptible to user-driven heuristic thresholds and extraneous distractors. Inspired by recent success of artificial intelligence, a deep learning based automated crack detection system called CrackSN was developed. An image dataset of concrete surface is collected by smartphone and carefully prepared in order to develop and train the CrackSN system. This proposed deep learning model, built on the Adam-SqueezeNet architecture, automatically learns the discriminative feature directly from the labeled and augmented patches. Hyperparameters of SqueezeNet are tuned with Adam optimization additive through the training and validation procedures. The fine-tuned CrackSN model outperforms state-of-the-art models in recent literature by correctly classifying 97.3% of the cracked patches in the image dataset. The success of CrackSN model demonstrated with light network design and outstanding performance provides a key step toward automated damage inspection and health evaluation for infrastructure.

The impact of cyanopic illuminance on evening light induced circadian effects

Circadian lighting aims to avoid the negative impacts of artificial lighting on the circadian system. Of particular concern are the negative effects induced by evening light exposure, such as the suppression of melatonin secretion and delayed circadian phase. The melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) play a key role in the circadian phototransduction processes. Therefore, popular metrics for “circadian illuminance”, such as equivalent melanopic lux (EML) and melanopic equivalent daylight D65 illuminance (m-EDI), are based solely on melanopic illuminance. However, some recent studies suggested that visual photo-receptors could also participate in the circadian phototransduction process. Especially, the S-cone-related cyanopic illuminance may also contribute to the light-elicited circadian responses.To investigate the actual role of cyanopic illuminance and the accuracy of the m-EDI and EML metrics, we designed a pair of general-lighting spectra with equivalent melanopic and photopic illuminance but very different cyanopic illuminance (40.5% difference achieved). Human-factor studies were conducted using this pair of spectra, which showed that saliva melatonin concentration and sleep efficiency were significantly higher under the lighting condition with greater cyanopic illuminance. These results suggest that cyanopic illuminance plays an important role in evening-light-induced circadian effects with an inhibitory behavior. On the other hand, cyanopic illuminance alone does not affect KSS-rated subjective alertness.Our findings suggest that incorporating cyanopic illuminance, in addition to melanopic illuminance, can enhance the accuracy of circadian illuminance metrics. This balanced approach can help achieve both precise quantification and convenience in circadian lighting design.

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.