LED Street Research Articles

A Deep Learning-Assisted Visible Light Positioning Scheme for Vehicles With Image Sensor

Visible light communication (VLC) based on image sensor (IS) as the receiver is one of the supplementary technologies of radio frequency communication. By combining with image processing technology, VLC has various applications in smart home, underwater communication and intelligent transportation system (ITS). In the paper, it focuses on the vehicle positioning service provided by VLC in ITS. For the weak image spatial separability caused by long-distance VLC transmission between the vehicle and the infrastructure, it will lead to serious deterioration in communication and positioning performance. Thus, a deep learning-assisted IS-based visible light positioning (VLP) scheme is proposed and experimentally demonstrated. At the transmitter, a novel coding method is proposed to support both short-distance and long-distance communication based on VLC in ITS. Meanwhile, it can meet the dimming requirements of LED road infrastructure. In addition, in the proposed VLP scheme, it uses an artificial neural network (ANN) to predict the location of the vehicle. It is demonstrated that long-distance communication, high-accuracy positioning, and LED dimming can be realized simultaneously. The results show that, by using the proposed scheme, as the transmission distance is 2 m, the bit error rate (BER) of system is 1.25 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−4</sup> . And the average positioning error is 19.8 mm at the maximum simulated distance of 30 m.

The Optical Design of a LED-Reflector Module in Road Illumination

In recent years, there has been a trend towards energy-efficient, long-lasting, environmentally friendly, and technology-compatible LED road luminaires. In this study, the optical design and analysis of the LED road luminaire model for the M1 and M2 illumination classes roads, which are the roads with the highest importance, have been carried out. In the research, the unique reflector design was made using SolidWorks 3D design software. XLamp CXA1520 LED light source by Cree company was preferred during the design. 21 LEDs were placed on the reflector at the ideal distance and LED luminaire model was created in LightTools illumination design software. A simulation study was performed for the LED luminaire model created on LightTools software and the distribution curve of luminous intensity was obtained. At the same time, the EULUMDAT (.ldt) file, which is required for road illumination analysis, was produced with LightTools software. The obtained .ldt file was transferred to DIALux illumination calculation program and simulated for M1 and M2 class roads. Illumination parameters obtained from DIALux analysis have been optimized by comparing them with the road illumination criteria accepted by International Commission on Illumination (CIE). It has been observed that the designed LED luminaire model significantly meets the M1 and M2 class road illumination criteria defined by CIE. In the study, it was also discussed what changes can be made in the optical material to meet all criteria.

Innovative Lighting Systems: Opportunities for Energy Savings

This paper analyses, from an energy flow perspective, the implementation of smart lighting systems in street lighting, where lights are dimmed to adapt to the flow of objects passing in a street. The research focus on the sustainability perspective of implementing a transition to smart lighting systems when compared to regular LED lighting. To account for externalities, the energy flow was addressed considering the extra electronic devices used in a smart lighting system (controllers, motion sensors, radars, and computers).&#x0D; &#x0D; To compare both traditional LED street lighting and smart lighting the paper started with a model of a 2.5-kilometre street, scaling up scenarios of the commune Ecublens, in the Swiss canton of Vaud, and then to half and all residential streets of Switzerland were examined to understand if the gains in energy savings are scalable. &#x0D; &#x0D; The research shows that, even with the additional electronic devices, the smart lighting system reduces the energy consumption of street lighting, even when considering the production of the extra components used. Financially, the extra costs of implementing smart lighting systems are offset by the savings in electricity consumption. Therefore, smart lighting systems for street lighting can be an environmentally and economically beneficial project to implement.

Comparison of energy efficiency and costs related to conventional and LED road lighting installations

Comparison of conventional (usually high-pressure sodium (HPS)) and LED luminaires in street/road lighting is not often based on photometrically equivalent lighting solutions and/or correct economic analysis, which may lead to either overestimation or underestimation of savings of any kind. Therefore, this paper presents a correct methodology for the determination of actual energy efficiency and cost indicators in street/road lighting. Both neutral white (NW) and warm white (WW) LEDs, all relevant street/road lighting classes and pole layouts were considered. Analyzing optimal lighting solutions, characterized by the lowest installed power, it was shown that when considering mesopic effects the average energy savings achieved comparing LED (NW and WW) with HPS lighting solutions amounted to 41–62% and 29–59%, respectively, while the ratio between the total costs of the comparable LED (NW and WW) and HPS lighting solutions belonged to the ranges 0.59–1.26 and 0.61–1.14, respectively. An expanded sensitivity analysis of the costs, carried out considering not only the usually taken discount and electricity cost rates, but also the LED package lifetime, showed that the last only slightly influences the total costs. The effects of the use of more efficient LED packages expected in the near future were also analyzed.

Impact of Thermal Dissipation on the Lighting Performance and Useful Life of LED Luminaires Applied to Urban Lighting: A Case Study.

Currently, LED technology is an established form of lighting in our cities and homes. Its lighting performance, durability, energy efficiency and light, together with the economic savings that its use implies, are displacing other classic forms of lighting. However, some problems associated with the durability of the equipment related to the problems of thermal dissipation and high temperature have begun to be detected, which end up affecting their luminous intensity and the useful life. There are many studies that show a direct relationship between the low quality of LED lighting and the aging of the equipment or its overheating, observing the depreciation of the intensity of the light and the visual chromaticity performance that can affect the health of users by altering circadian rhythms. On the other hand, the shortened useful life of the luminaires due to thermal stress has a direct impact on the LCA (Life Cycle Analysis) and its environmental impact, which indirectly affects human health. The purpose of this article is to compare the results previously obtained, at different contour temperatures, by theoretical thermal simulation of the 3D model of LED street lighting luminaires through the ANSYS Fluent simulation software. Contrasting these results with the practical results obtained with a thermal imaging camera, the study shows how the phenomenon of thermal dissipation plays a fundamental role in the lighting performance of LED technology. The parameter studied in this work is junction temperature (Tj), and how it can be used to predict the luminous properties in the design phase of luminaires in order to increase their useful life.

Design of a hybrid wind-solar street lighting system to power LED lights on highway poles

&lt;abstract&gt; &lt;p&gt;This is an experimental study that investigates the performance of a hybrid wind-solar street lighting system and its cost of energy. The site local design conditions of solar irradiation and wind velocity were employed in the design of the system components. HOMER software was also used to determine the Levelized Cost of Energy (LCOE) and energy performance indices, which provides an assessment of the system's economic feasibility. The hybrid power supply system comprised of an integrated two photovoltaic (PV) solar modules and a combined Banki-Darrieus wind turbines. The second PV module was used to extend the battery storage for longer runtime, and the Banki-Darrieus wind turbines were used also to boost the battery charge for times when there is wind but no sunshine, especially in winter and at night. The results indicated that the hybrid system proved to be operating successfully to supply power for a street LED light of 30 watts. A wind power of 113 W was reached for a maximum wind speed that was recorded in the year 2021 of 12.10 m/s. The efficiency of the combined Banki-Darrieus wind turbine is 56.64%. In addition, based on the HOMER optimization analysis of three scenarios, of which, using either a solar PV system or the combined wind turbines each alone, or using the hybrid wind-solar system. The software results showed that the hybrid wind-solar system is the most economically feasible case.&lt;/p&gt; &lt;/abstract&gt;

Development of New Radar and Pyroelectric Sensors for Road Safety Increase in Cloud-Based Multi-Agent Control Application

The paper concentrates on the design, architecture, and monitoring of smart LED street lighting control, with focus on traffic safety and safe road infrastructure. The use of a CMAS (Cloud-Based Multi-Agent System) as a possible framework is investigated. The work is based on previous developments by the authors in the production and design of close and long-range hybrid Pyroelectric Infrared (PIR) motion detection sensors. It also introduces the advances in radar-type sensors used in smart SLC (street lighting control) application systems. The proposed sensor solutions can detect the road user (vehicle or pedestrian) and determine its movement direction and approximate speed that can be used for dynamic lighting control algorithms, traffic intensity prediction, and increased safety for both driver and pedestrian traffic. Furthermore, the street lighting system infrastructure can monitor city environmental parameters, such as temperature, humidity, CO2 levels, thus increasing levels of safety and security for smart cities. Utilising other hybrid systems within intelligent street lighting applications represents a new specialisation area in both energy-saving, safety awareness, and intelligent management.

Visual Perception in External Lighting Conditions

LED street lighting is a topical trend in modern outdoor lighting. High light output of LEDs creates all conditions for modernization of electric lighting networks in Ukraine. Human vision is a complex process associated with retinal light perception. Vision is divided into: day vision, night vision, and twilight vision. The function of the eye is highly dependent on the distribution of brightness in the field of vision. The spectral sensitivity of photoreceptors varies for different wavelengths of the visible spectrum and different levels of light intensity. The rationing of the lighting installation is based on detailed studies of the observer’s visual performance depending on different lighting conditions. One of the main luminous parameters that can easily be measured objectively is illumination. Brightness as a function of illumination, the observer’s position and the spectral coefficient of the working surface reflection is more informative, but has some difficulty in measuring. There is a clear need to develop a system that would make it possible to uniquely assess the visual efficiency of a given spectral composition under certain observation conditions. It was decided to introduce the term equivalent brightness as the parameter of such a system. The difficulty of using the function Vek(λ,Lek) to calculate the equivalent brightness is the function’s dependence Vek(λ,Lek) on Lek. The aim of the study is to approximate the function of the relative spectral luminous efficiency in mesopathic regions by a set of standard CIE functions that do not depend on the value of equivalent luminosity. The calculation method Vek(λ,Lek) is proposed using only two normalized functions of the relative spectral radiation efficiency for day V(λ) and night V'(λ) vision. The use of such approximation function makes it possible to determine the equivalent brightness, which adequately reflects the level of visual perception under the conditions of ambient illumination, based on the photometric brightness of the light source. To calculate Vek(λ,Lek) we use the ICE recommended functions of relative spectral light efficiency for the twilight vision, which are based on the spectral composition of the blackbody radiation with a color temperature of 2042 K. The use of the developed methodology provides results that more accurately characterize the efficiency of light sources in outdoor lighting installations compared to the results of calculations obtained when using standard methods.

Plasma-assisted template removal and consolidation of silica coatings on polycarbonate

This paper presents a fast and efficient method of removing the template from silica thin films on polycarbonate. Radiofrequency-generated oxygen plasma induced the decomposition of the non-ionic surfactant. The reference samples were silica coatings on silicon, which had different pore sizes. We removed the surfactant by solvent extraction and calcination from these samples. Grazing incidence angle X-ray diffraction analysis shows a highly ordered arrangement of mesopores. The formation of the face-centred cubic structure of mesopores is independent of the substrate and the template removal method. Atomic force microscopy analysis showed open-pore channels after oxygen plasma etching. It also proved that the ammonia treatment increases the hardness of the layer. A short air-plasma treatment is effective for the consolidation of the silica layer and improves the abrasion resistance of the layer on polycarbonate. Air plasma treatment is an alternative to the long heat treatment process. We performed environmental tests according to the relevant ISO standards for optical coatings. Air plasma treated silica coatings have passed all the weathering tests. Therefore, it can be used in outdoor applications, such as a protective layer for the plastic cover of LED street lights. These thin films on polycarbonate have at least one year of service life and are weather-resistant. Plasma treatment can consolidate the silica network and the thin films on polycarbonate have high light transmission (T = 98.8 %).

Green Electric Energy Technology in the Automatic Monitoring System of Electrical Street Lamp Lighting

Low-carbon economy has become the focus of global development, and the concept of environmental protection has become increasingly popular. As a high-tech industry, LED green lighting not only represents the future development direction of green lighting, but also sets an example in environmental protection and energy saving. The article introduces a wireless monitoring system that Kingsun Optoelectronics uses the latest ZigBee and GPRS technologies for LED street lights. The real-time data in the street lamp controller of the system is transmitted to the cloud server through the data concentrator through the ZigBee node, and the cloud server processes the data and distributes it to the corresponding monitoring terminal. At the same time, the remote control of each wind and solar complementary street lamp can also be realized through each terminal. Experiments have proved that the system realizes the intelligent management and monitoring of street lights based on saving electric energy and ensuring the reliability of lighting. The use of this system can realize the monitoring of all street lights without leaving the house, and finally realize the low-carbon economy and sustainable development of urban lighting.

Erratum to Effect of adaptive control on the LED street luminaire lifetime and on the lifecycle costs of a lighting installation

Erratum to Effect of adaptive control on the LED street luminaire lifetime and on the lifecycle costs of a lighting installation

Systematic Research on the Heat Dissipation Channel of High Power LED Street Lamps

This article mainly studies the thermal characteristics of light source of the street lamp, and systematically analyzes the effective ways of heat transfer and heat dissipation of street lamp. Based on experiments and finite element simulations, the heat dissipation channels of street lights were studied, and the weak links of heat transfer and heat dissipation were analyzed, and the heat dissipation structure of street lamp was optimized. The experimental results show that the junction temperature of the chip is lower than 90 °C in the steady state, and the luminous efficiency decreases by 5.93%. In order to ensure the efficiency and reliability of the street lamp, it is recommended that the junction temperature of the street lamp be controlled below 85 °C. After analyzing the arrangement of the chips, silicone grease with different thermal conductivity and aluminum substrate, it is found that the substrate is the bottleneck affecting effective heat transfer, and the use of diamond like carbon metal core printed circuit board (DLC-MCPCB) can reduce the junction temperature by 17.04 °C. Through the grid design of shell of the street lamp, the heat dissipation effect of the street lamp surface can be enhanced, and the junction temperature can be reduced by 7.04 °C. Based on these studies, the optimal design model of street lamp was obtained, which provides guidance for practical applications.

Effect of adaptive control on the LED street luminaire lifetime and on the lifecycle costs of a lighting installation

We report for the first time the effect of ageing due to adaptive control of lighting on the lifecycle costs of luminaire installations. Two types of LED street luminaire were aged (1) as the luminaire lit for 9 hours and then switched off for 3 hours and (2) under intensive ageing using adaptive control conditions mimicking presence of vehicles, where the luminaires were switched with 30-second interval between 100% and 20% power within the cycle of (1). The test continued for 32,000 hours. Luminaire lifetime was found to decrease by 10% due to the intensive adaptive control, which exaggerates the ageing as compared to real traffic conditions. We estimate that a realistic rate of dimming cycles would decrease the luminaire lifetime by 0–2%, increasing the lifecycle costs of a lighting installation by 0–0.7%. With a traffic-aware control system, capable of 50% energy saving in lighting, the lifecycle costs are estimated to reduce by 25% as compared to a similar LED luminaire installation without traffic-aware control, outweighing the costs due to the reduced lifetime. The smart controlling of lighting is considered as a useful way to meet future energy saving targets.

LED lighting threatens adult aquatic insects: Impact magnitude and distance thresholds

Abstract Artificial light at night (ALAN) is increasing globally, and changing in quality due to the installation of white LED street lighting. ALAN is a threat to biodiversity and ecosystem functioning, yet important knowledge gaps exist regarding the magnitude of impacts and how these vary between habitats and levels of exposure. The disturbance of aquatic habitats by ALAN is of particular concern as human settlements and activities are often located near waterbodies, and many aquatic species are sensitive to ALAN. Focusing on adult aquatic insects, an experimental approach was employed in the riparian zone of a structurally simplified river within a dark rural landscape. Two studies were used to (a) estimate the magnitude of the capture effect of white LED lamps and (b) to explore how captures at lamps vary with their distance from the river, and define any distance thresholds. Both studies sampled mayflies (Ephemeroptera), caddisflies (Trichoptera) and true flies (Diptera) repeatedly during mid‐to‐late summer using modified flight intercept traps positioned adjacent to portable LED lamps. In Study A, lit traps were paired with unlit controls. In Study B, lit traps were positioned at six distances up to a maximum of 80 m from the stream edge. For each of the three study orders, captures were significantly higher in the lit treatment compared to the dark control, with medium to large effect sizes. For all study orders, captures at lamps significantly reduced with increasing distance from the river edge. Rapid declines in captures were recorded for Trichoptera (from 10 m) and Ephemeroptera (40 m), with a more gradual decline in Diptera from 60 m that continued up to the maximum sample distance. Previous research indicates that LED lighting can be less attractive to flying insects than broader spectrum alternatives. However, this study demonstrates that the effects of white LED lamps on flying adult aquatic insects should not be dismissed and can extend far from aquatic habitats. As a precautionary approach, and until finer recommendations are available, we recommend that LED lamps should be excluded from a buffer zone of ca. 40–60 m around rivers.

A method of fast quality control inspection of loop heat pipe

The dynamic behaviour of loop heat pipe (LHP) changes with heat load and physical properties of LHP such as fluid charging, wick material, and tolerance in manufacture. The start-up phenomena of a LHP can be classified into four modes, according to the heat load Qin : failure mode, oscillating mode, overshoot mode, and normal mode. It is found that the operation mode is related to the rate of temperature rise in evaporator during initial transient performance using a step heating load. The abnormal high rate of temperature rise can be observed for LHP with failure, oscillating or overshoot mode performance. Based on this phenomenon, the normal-mode performance of LHP can be assured from a short transient test in about 80s using a step heat load, instead of using steady-state test (taking 1,800s). This transient test method has been applied in the quality inspection of commercial loop heat pipe in mass production. No LHP failure was found for more than 10 years for about 30,000 sets of street LED luminaires designed with LHP.

The linearization of the relationship between scene luminance and digital camera output levels

The linearization of the relationship between scene luminance and digital camera output levels

The Drive towards Optimization of Road Lighting Energy Consumption Based on Mesopic Vision—A Suburban Street Case Study

This paper presents the research of optimization of road lighting energy consumption by utilizing the fact of human twilight and night vision (mesopic vision) dependency on luminance level and lamp’s light spectral composition. The research was conducted for a suburban street illuminated by smart LED road luminaires with a luminous flux control system with which different luminance levels can be achieved on the road. This road is an access road leading to a town located on the outskirts of Warsaw which is the capital of Poland and a large metropolitan area. Therefore, the traffic here is quite heavy on this road in the morning and in the evening and it is very light at other times of the day. In accordance with EN 13201 standard, lighting control can be applied to illuminate this road. This paper compares energy consumption for different lighting scenarios of the road in question. In the first scenario, the road luminance is compliant with M4, M5, and M6 lighting class requirements depending on the time of the day. In the second scenario, for each M lighting class, the values of luminance levels provided by EN 13201 standard have been reduced to the values resulting from their conversion to the corresponding mesopic luminance values. The conducted research has shown that a 15% saving per year in electricity consumption on the road is possible with such a conversion. Therefore, energy efficiency of a lighting installation can be improved by matching the lighting levels provided by the standard to the mesopic vision.

Voltage distortion in LED street lighting installations

The paper considers two power quality issues: voltage distortion and voltage drop along the pole lines of different LED street (road) lighting installations. The research includes three parts: (1) development of a novel model and the corresponding software for calculating voltage harmonics in the three-phase LED street lighting installations, where the load is nonsymmetrical and nonlinear. The model is based on the application of symmetrical components and the impedance per phase model. (2) Experiments on two sections of a pilot street lighting installation, one with 6 poles with neutral white and the other with 5 poles with warm white LED luminaires (the former were with conventional, and the latter with improved drivers regarding harmonic emissions). Their results were used to define harmonic characteristics of the LED luminaires and validate the model. (3) The developed software was applied to four typical street (road) lighting installations, two with a single-sided and two with a central pole layout. The major outcome was the determination of the maximum permissible number of the LED luminaires which can be connected to the feeding cable without exceeding any of the limits related to voltage drop, total voltage harmonic distortion and individual voltage harmonics in either the full or reduced street lighting regimes.

The LEDs luminance distribution measurement quality dependency on image focusing

Luminance measurements are used in a vast range of lighting technology fields. The author’s research has proved that measuring the luminance distribution on light source surface is the most challenging part of this process. The research has been conducted for a commercially available digital luminance distribution meter, with the goal of analyzing the influence of image focus settings and exposure parameters on the measured luminance values. It has been concluded that the incorrect image focus and inadequately matched exposure parameters (distance from the workpiece) contribute to quantitative changes in the information on luminance distribution on the LED surface and affect the precision the maximum luminance determination. Full Text: PDF ReferencesC. Xu, H. Cheng, and Y. Feng, "Optical design of rectangular illumination with freeform lenses for the application of LED road lighting," Frontiers of Optoelectronics, 2017, CrossRef D. Czyzewski, "LED substitutes of conventional incandescent lamps," Przeglad Elektrotechniczny, vol. 88, no. 11A, pp. 123-127, 2012. DirectLink W. R. Ryckaert, K. A. G. Smet, I. A. A. Roelandts, M. Van Gils, and P. Hanselaer, "Linear LED tubes versus fluorescent lamps: An evaluation," Energy and Buildings, 2012, CrossRef X.-H. Lee, I. Moreno, and C.-C. Sun, "High-performance LED street lighting using microlens arrays," Optics Express, 2013, CrossRef D. Czyzewski, "The street lighting luminaires with LEDs," Przeglad Elektrotechniczny, vol. 86, pp. 276-279, 2009. DirectLink D. Mozyrska, M. Wyrwas, and I. Fryc, "The determination of the LEDs colorimetric parameters, in the range of their operating temperature," Przeglad Elektrotechniczny, vol. 93, no. 4a, pp. 232-234, 2012. DirectLink J. Kowalska and I. Fryc, "Colour rendition quality of typical fluorescent lamps determined by CIE colour fidelity index and colour rendering index," Przeglad Elektrotechniczny, vol. 95, no. 7, pp. 94--97, 2019, CrossRef J. Kowalska, "Analysis of parameters describing the quality of the color rendering of light sources according to the IES TM-30-15 and the CIE 013.3-1995," Przeglad Elektrotechniczny, vol. 93, no. 6, pp. 50--54, 2017, CrossRef K. Houser, M. Mossman, K. Smet, and L. Whitehead, "Tutorial: Color Rendering and Its Applications in Lighting," LEUKOS - Journal of Illuminating Engineering Society of North America, vol. 12, no. 1-2, pp. 7-26, 2016, CrossRef S. Słomiński, "Identifying problems with luminaire luminance measurements for discomfort glare analysis," Lighting Research and Technology, 2016, CrossRef D. Czyzewski, "Investigation of COB LED luminance distribution," 2016, CrossRef M. Jongewaard, "Guide to selecting the appropriate type of light source model," in Proc.SPIE, Aug. 2002, vol. 4775, CrossRef D. Czyzewski, "Selected problems of defining the luminous area of electroluminescent diodes," Przeglad Elektrotechniczny, vol. R. 84, nr 8, pp. 125-128, 2008. DirectLink C. D. Galatanu, "Improving the Luminance Measurement from Digital Images," in 2019 International Conference on Electromechanical and Energy Systems (SIELMEN), 2019, pp. 1-4. CrossRef I. Fryc and E. Czech, "Application of optical fibers and CCD array for measurement of luminance distribution," in Proc. SPIE 5064, Lightmetry 2002: Metrology and Testing Techniques Using Light, 2003, pp. 18-21, CrossRef I. Fryc and E. Czech, "Spectral correction of the measurement CCD array," Optical Engineering, 2002, CrossRef I. Fryc, "Angular characteristics of a silicon detector spectral sensitivity corrected by an absorption filter," in Proc. SPIE 4517, Lightmetry: Metrology, Spectroscopy, and Testing Techniques Using Light, 2001, pp. 42-45, CrossRef I. Fryc, "Accuracy of spectral correction of a CCD array for luminance distribution measurement," in Proc. SPIE 5064, Lightmetry 2002: Metrology and Testing Techniques Using Light, 2003, pp. 38-42, CrossRef M. Moeck and S. Anaokar, "Illuminance analysis from high dynamic range images," LEUKOS - Journal of Illuminating Engineering Society of North America, pp. 211-228, 2006, CrossRef D. Czyżewski, "Research on luminance distributions of chip-on-board light-emitting diodes," Crystals, 2019, CrossRef

Evaluation of urban light-emitting diodes lighting facilities’ impact on landscape shrub

In the field of urban lighting and landscape planning, most researchers focus on how to make lighting meet people’s demand, while few researchers consider the impact of lighting systems on landscape plants. Based on statistical methods and field measurements, the brightness data of street lamps in a street of Shanghai were collected, and these data were compared to the shrub growth data of the street green belt. The results show that LED street lighting facilities have a promotion effect on the growth rates of shrub’s new shoots, while it also have effect on shrub leaves’ greenness. This study discussed a statistically method to evaluate the impact of urban lighting system on landscape plants, providing theoretical and methodological support for unban lighting and ecological landscape design. Besides, this study could also help further study about the impact of urban lighting on Urban ecosystem.