Determining minimum visibility levels in different road lighting scenarios

2017 ◽  
Vol 50 (7) ◽  
pp. 1045-1056 ◽  
Author(s):  
B Buyukkinaci ◽  
S Onaygil ◽  
O Guler ◽  
MB Yurtseven
Keyword(s):  
Object Detection ◽  
Light Sources ◽  
Colour Temperature ◽  
Laboratory Environment ◽  
Road Lighting ◽  
Critical Object ◽  
Test Road

This study investigates visibility levels for different road lighting scenarios. Four different road lighting classes (M2, M3, M4, M5), two different colour temperature luminaires (4000 K and 6000 K) and four different critical object reflectances (0.20, 0.30, 0.40, 0.50) were used to determine the effects of lighting classes and colour temperatures on the critical object detection. In total, 1920 photographs were taken on a test road and visibility levels were calculated for each case. From these 1920 visibility levels, photographs corresponding to 245 visibility level values ranging from 1 to 9 were selected and evaluated by 30 subjects aged between 25 and 35 years in a laboratory environment. As a result of the study, it was shown that visibility levels are between 7.0 and 8.5 for road lighting classes ranging from M2 to M5, illuminated by light sources with different colour temperatures, for 100% detection of critical objects. This result is in line with the suggested VL values changing between 7 and 10 in the literature.

The Influence Of The Led Luminaires Electrical Parameters On Their Correlated Colour Temperature During Operation Mode

2020 ◽  
pp. 89-96
Author(s):  
Sergei S. Kapitonov ◽  
Alexei S. Vinokurov ◽  
Sergei V. Prytkov ◽  
Sergei Yu. Grigorovich ◽  
Anastasia V. Kapitonova ◽  
...  
Keyword(s):  
Operation Mode ◽  
Light Sources ◽  
Electrical Parameters ◽  
Colour Temperature ◽  
Radiation Spectra ◽  
Service Period ◽  
Close Proximity ◽  
Definition Of ◽  
Comprehensive Study

The article describes the results of comprehensive study aiming at increase of quality of LED luminaires and definition of the nature of changes in their correlated colour temperature (CCT) in the course of operation. Dependences of CCT of LED luminaires with remote and close location of phosphor for 10 thousand hours of operation in different electric modes were obtained; the results of comparison between the initial and final radiation spectra of the luminaires are presented; using mathematical statistics methods, variation of luminaire CCT over the service period claimed by the manufacturer is forecast; the least favourable electric operation modes with the highest CCT variation observed are defined. The obtained results have confirmed availability of the problem of variation of CCT of LED luminaires during their operation. Possible way of its resolution is application of more qualitative and therefore expensive LEDs with close proximity of phosphor or LEDs with remote phosphor. The article may be interesting both for manufacturers and consumers of LED light sources and lighting devices using them.

Design of Solar-Powered LED Road Lighting System

2019 ◽  
pp. 75-85
Author(s):  
Canan Perdahci ◽  
Hamdi Ozkan
Keyword(s):  
High Pressure ◽  
Renewable Energy Sources ◽  
Junction Temperature ◽  
Mercury Vapour ◽  
Light Sources ◽  
Street Lighting ◽  
Led Light ◽  
Road Lighting ◽  
Lighting Systems ◽  
High Pressure Sodium Lamp

Turkey is rich in terms of renewable energy sources and, therefore, is now encouraging the use of sustainable clean lighting systems in road applications. High pressure sodium lamp is the most widely used type in main roads, but other types of lamps such as mercury vapour lamps or metal halide lamps can be utilized for street lighting. Since it enables energy and money saving, LED light technology has replaced high pressure sodium lamps nowadays. Once solar power system (PV) is integrated with LED lamp for street lighting, the amount of saving and local impact might be enriched. LEDs used as light sources in road lighting luminaires with rising lumen values, decreasing junction temperature, higher colour rendering efficiency, longer lifetime have become more efficient than many light sources with the latest developments. Since the structure of the luminaires in which the LED light sources are used differs from that of the conventional light sources, the optical, thermal and electrical design of the LED luminaires must be considered differently. Thus, this study concentrates upon design considerations and the operating principle of solarpowered LED road lighting luminaire in details. Also, a simple solar panel system was designed and the economical values obtained at the end of 20 years were compared when using the ongrid system and the off-grid system.

scholarly journals Light Emitting Diodes (LED) for Aqueous Light Bleaching of Paper

2019 ◽  
Vol 40 (2) ◽  
pp. 69-95
Author(s):  
Benjamin Kirschner ◽  
Irene Brückle ◽  
Ute Henniges
Keyword(s):  
Carbonyl Group ◽  
High Performance ◽  
Molar Mass ◽  
Light Exposure ◽  
Light Sources ◽  
Light Emitting ◽  
Colour Temperature ◽  
Negative Effect ◽  
Hid Lamps ◽  
Reference Samples

Abstract High performance daylight LED lamps are compared with HID lamps for light bleaching of paper. The LED can be placed in closer proximity to the object than the HID lamps, causing a significantly increased, uniform light exposure. Two commercial LED systems with 4000 K and 6500 K colour temperature were installed in a convertible test device with a polypropylene tray in default exposure distance of 10 cm and 20 cm. A HID lamp in 60 cm and 120 cm distance served as a reference. Samples of two naturally aged rag papers were bleached with both LED systems and with the HID while immersed in water. All three light sources increased brightness (CIELAB L*), though the LEDs with 4000 K colour temperature were most effective. They had no negative effect on the molar mass and the cellulose carbonyl group content while LEDs with 6500 K colour temperature caused molar mass decrease and carbonyl group increase. LEDs of a 4000 K or similar colour temperature are a promising option for improved light bleaching of paper, reducing the treatment and aqueous exposure time and eliminating UV radiation.

Evaluation Index Study of Students’ Physiological Rhythm Effects under Fluorescent Lamp and LED

2012 ◽  
Vol 433-440 ◽  
pp. 4757-4764 ◽  
Author(s):  
Yong Hong Yan ◽  
Tang G. Lee ◽  
Yang Guan ◽  
Xiang De Liu
Keyword(s):  
Luminance Level ◽  
Evaluation Index ◽  
Light Sources ◽  
Fluorescent Lamp ◽  
Colour Temperature ◽  
Learning Efficiency ◽  
Fluorescent Lamps ◽  
Comprehensive Index ◽  
Index Study ◽  
Typical Colour

The influence of artificial classroom light source’s colour temperature to students’ learning efficiency and physiology rhythm is the focus of this study. An experiment compares a subjects’ learning efficiency, asthenopia and brain fag under different luminance level of three typical colour temperatures from T5 fluorescent lamps and LED. Using comprehensive index ε and norm identification Ψ for quantitative evaluation and testing under different lighting environments, we determined the best colour temperature of two experimental light sources. We also determined the best combinations of illuminance value and the colour temperature that should be avoided in classroom lighting. Experiment shows that spectrum difference obviously effects comprehensive index ε and norm identification Ψ. For learning efficiency and health of people, there need to be improvement in the spectrum of fluorescent lamps and LEDs

scholarly journals Energy-saving quality road lighting with colloidal quantum dot nanophosphors

Nanophotonics ◽  
2014 ◽  
Vol 3 (6) ◽  
pp. 373-381 ◽  
Author(s):  
Talha Erdem ◽  
Yusuf Kelestemur ◽  
Zeliha Soran-Erdem ◽  
Yun Ji ◽  
Hilmi Volkan Demir
Keyword(s):  
Energy Saving ◽  
Light Sources ◽  
Experimental Proof ◽  
Street Lighting ◽  
Light Emitting ◽  
The Road ◽  
Road Lighting ◽  
The Usa ◽  
The Uk ◽  
Conversion Efficiencies

AbstractHere the first photometric study of road-lighting white light-emitting diodes (WLEDs) integrated with semiconductor colloidal quantum dots (QDs) is reported enabling higher luminance than conventional light sources, specifically in mesopic vision regimes essential to street lighting. Investigating over 100 million designs uncovers that quality road-lighting QD-WLEDs, with a color quality scale and color rendering index ≥85, enables 13–35% higher mesopic luminance than the sources commonly used in street lighting. Furthermore, these QD-WLEDs were shown to be electrically more efficient than conventional sources with power conversion efficiencies ≥16–29%. Considering this fact, an experimental proof-of-concept QD-WLED was demonstrated, which is the first account of QD based color conversion custom designed for street lighting applications. The obtained white LED achieved the targeted mesopic luminance levels in accordance with the road lighting standards of the USA and the UK. These results indicate that road-lighting QD-WLEDs are strongly promising for energy-saving quality road lighting.

Colour preference, naturalness, vividness and colour quality metrics, Part 1: Experiments in a room

2016 ◽  
Vol 49 (6) ◽  
pp. 697-713 ◽  
Author(s):  
TQ Khanh ◽  
P Bodrogi ◽  
QT Vinh ◽  
D Stojanovic
Keyword(s):  
Quality Metrics ◽  
Saturation Effect ◽  
Light Sources ◽  
Quality Indices ◽  
Colour Preference ◽  
Colour Temperature ◽  
Semantic Categories ◽  
Interval Scales ◽  
Office Lighting ◽  
Spectral Design

In Part I of this work, observers scaled colour preference, naturalness and vividness visually on interval scales (0–100) labelled by semantic categories (e.g. ‘moderate’, ‘good’ and ‘very good’) in the context of office lighting. Five customary light sources without object saturation effect illuminated a table with coloured objects in a real room. The observers’ assessments were predicted by recent colour quality indices and selected pairs of indices combined linearly. Criterion values of the indices for ‘good’ colour preference and vividness were determined to provide a usable acceptance limit for the spectral design and evaluation of light sources. To predict colour preference, correlated colour temperature turned out to be useful. In Part 2 of this work, another experiment with the same method but using multi-LED spectra with more object saturation will be analysed and the two datasets will be merged.

A Novel Strategy For Transformation Of Conventional Road Lighting To Smart Road Lighting

2020 ◽  
pp. 97-105
Author(s):  
Mustafa Eyyup Gursoy ◽  
Burak Dindar ◽  
Omer Gul
Keyword(s):  
Low Cost ◽  
Road Lighting ◽  
Test Road ◽  
Innovative Solution ◽  
Cost Of Production ◽  
Lighting Systems ◽  
Novel Strategy ◽  
The Cost ◽  
Electrical Installation ◽  
Led Luminaire

In recent years, smart road lighting (SRL) design and application researches has been increasing rapidly. However, SRL applications remain pilotproject and cannot become widespread sufficiently. Main reason for this is that, although the cost of production of LED luminaires is reduced, when existing road lighting systems are transformed to LED road lighting, existing electrical installations and lighting poles cannot be used. Increased investment costs due to electrical installation and poles renovation, decrease interest in SRL transformation. In this study, an innovative solution is developed to decrease the costs of the SRL. First, a new LED luminaire is designed, which can work without changing the installations and poles of the existing projects. Then a test road is created using DIALux software, and the newly designed lighting installation is compared with completely redesigned one and conventional road lighting. Thus, contributions are provided for spreading of the SRL transformation, using low cost SRL approach.

A Study on the Effect of Light Sources on the Colour of Objects

2020 ◽  
pp. 47-52
Author(s):  
Fatih Atalar ◽  
Kerim Uzun ◽  
Ahmet Gedikli ◽  
Aysel Ersoy Yilmaz ◽  
Mukden Ugur
Keyword(s):  
Light Source ◽  
Light Sources ◽  
Halogen Lamp ◽  
White Led ◽  
Dominant Wavelength ◽  
Surface Type ◽  
Colour Temperature ◽  
Effect Of Light

Lighting is one of the basic aspects that eases our lives and increases its quality. We use lighting tools in many places such as homes, streets, work places, hospitals, factories, etc. In this study, the effects of the light source and the surface of the object on features like colour temperature, glare, colour (perceived) and dominant wavelength is analysed. Four light sources such as a warm white halogen lamp, warm white LED source and two cool white LED sources were used. In the light measurements, 10 paper surfaces and 8 cloth surfaces were selected as the surface type. Colours of the surfaces were selected among the main colours on the colour locus. Light, reflected from surface was recorded with Konica Minolta CS-200 model. All results were indicated and compared with each other.

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