Spectral characteristics of road surfaces and eye transmittance: Effects on energy efficiency of road lighting at mesopic levels

2017 ◽  
Vol 50 (6) ◽  
pp. 842-861 ◽  
Author(s):  
OU Preciado ◽  
ER Manzano
Keyword(s):  
Energy Efficiency ◽  
Light Source ◽  
Spectral Characteristics ◽  
The Other ◽  
Visual Performance ◽  
Light Sources ◽  
Surface Reflectance ◽  
Road Lighting ◽  
Road Surfaces ◽  
Final Effect

In 2010, the CIE published a recommended system for mesopic photometry based on visual performance. According to this system, scenes illuminated at mesopic levels with light sources of high S/P ratio, will produce better visual performance than those illuminated with light sources of a lower S/P ratio at equal photopic luminance. However, there could be other factors affected by SPD that, when quantified, could lead to a contradictory final effect. The scope of this paper was to evaluate how road lighting is affected by the spectral road surface reflectance and by the human eye transmittance as people get older. Our results suggest that the benefits of considering the mesopic vision effect for light sources with high S/P ratios are totally counteracted by the other two effects at mesopic luminances between 0.75 cd/m2 and 1.73 cd/m2 for people between 20 and 60 years of age, depending on the light source and the age of observers.

Influence of the Parameters of Light Source on Observers’ Visual Performance

2015 ◽  
Vol 731 ◽  
pp. 124-128
Author(s):  
Min Huang ◽  
Zhen Zheng ◽  
Huan Jiang ◽  
Hao Xue Liu
Keyword(s):  
Light Source ◽  
Reading Rate ◽  
Mental Capacity ◽  
Visual Performance ◽  
Color Temperature ◽  
Light Sources ◽  
Accuracy Index ◽  
The Given ◽  
Dose Experiment

In order to investigate the influence of the light source with different illuminance and color temperature on the observers’ visual performance, five kinds of light sources were selected, named LED1, LED2, LED3, LED4 and Fluorescent, which have different illuminance or color temperature. 3 series of visual experiments, such as the ‘find out’ experiment, compared experiment, dose experiment were designed.13 observers were organized to carry out the experiment in the given time in turn. The reading rate, accuracy , index of mental capacity (IMC) and visual comfortable level score were analyzed, the results indicated that the light source with the lower color temperature and medium illuminance has the best visual performance and comfortable visual feel.

scholarly journals Development of portable device for measurement of dynamic and static light-emission WOLED characteristics

2021 ◽  
Vol 1 (1(57)) ◽  
pp. 30-33
Author(s):  
Ihor Helzhynsky ◽  
Stepan Kutsiy ◽  
Andriy Veryha ◽  
Khrystyna Ivaniuk ◽  
Taras Dudok
Keyword(s):  
Light Source ◽  
Data Exchange ◽  
Light Emission ◽  
Spectral Characteristics ◽  
Light Flux ◽  
Luminous Flux ◽  
Visible Range ◽  
Light Sources ◽  
Measuring Device ◽  
Routine Work

The research object of this work is the parameters of organic light-emitting diodes, namely power and luminous flux. Determination of these parameters can be carried out using a photodiode and requires measuring the dark current of the sensor (photodiode), measuring the current of the photodiode when illuminated by the LED under investigation. And also take into account the relationship between the light flux received by the sensor and its output current, and take into account the spectral characteristics of the sensor. Calculate the investigated parameters of the LED based on the measurements. Carrying out these measurements requires laboratory instruments and workplace organization, and further calculations are routine work. It is possible to increase the measurement accuracy by improving the existing methods for measuring the required parameters, and it is possible to automate the process of measurements and calculations using a modern microprocessor radioelement base. Microcontrollers are widespread such radioelements. They have the necessary peripherals for independent operation and have sufficient computing power to implement the required measuring device. Its application makes it possible to automate the measurement process, carry out the necessary calculations, save correction constants, accumulate and process the obtained data, analyze these received data, exchange data with a computer, etc. So, the work is aimed at developing a methodology that will allow the simultaneous measurement of power and luminous flux of planar light sources. And also on the feasibility of this technique in the device and software with the ability to measure the power of the light source in an arbitrary band of the spectral visible range. Thus, it is possible to determine what power in watts a light source emits with the dynamics of supply currents in the optical bands, knowing the spectrum of this source without using glass filters. So, the result of applying the technique is to determine the power of light radiation (in watts) or the luminous flux (in lumens) of the emitter (light sources).

scholarly journals Influence of a Light Source Installed in a Luminaire of Opal Sphere Type on the Effect of Light Pollution

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 306 ◽  
Author(s):  
Przemyslaw Tabaka ◽  
Pawel Rozga
Keyword(s):  
Light Source ◽  
Spectral Distribution ◽  
Spectral Characteristics ◽  
Measurement Data ◽  
Luminous Flux ◽  
Light Pollution ◽  
Light Sources ◽  
Pollution Effect ◽  
The Impact ◽  
Effect Of Light

The article presents the results of the studies concerning the influence of a light source installed in luminaire of opal sphere type on the light pollution effect of the night sky. It is known from literature reports that the effect of light pollution is influenced by the spectral distribution of light. Although the influence of the spectral distribution has been widely studied from different perspectives, there is still a need to study this phenomenon—for example, from the point of view of the spectral reflection properties of the ground, on which the lanterns are installed. Hence, the above-mentioned aspect was considered in the authors’ investigations. The luminaire considered has been equipped with 20 different light sources, including the latest generation of lamps (light-emitting diodes, LEDs) as well as the conventional ones. With respect to these light sources, the measurements of light distribution and spectral distribution of emitted radiation of the luminaire were performed. Having these measurement data, the simulations were carried out using the DIALux software, and the calculations were made using the specially prepared calculation tool. On the basis of the results obtained in this way this was stated that the type of light source installed in the luminaire has a significant effect on the sky glow. An important factor affecting light pollution is not only the value of the luminous flux emitted upward but also the spectral characteristics of the emitted radiation, the impact of which is most noticeable. The conclusions from the studies indicate the next steps in the analysis of the light pollution effect. These steps will be focused on extended analysis of LEDs as modern and developed light sources.

COLOUR FIDELITY AND ILLUMINANCE TRADE-OFF: TESTING LIGHTING VALUES

2021 ◽  
Author(s):  
J.A. Veitch ◽  
L.A. Whitehead
Keyword(s):  
Energy Efficiency ◽  
Light Source ◽  
Reflectance Spectra ◽  
Source Spectrum ◽  
Light Sources ◽  
Trade Off ◽  
Luminous Efficacy ◽  
Reading Task ◽  
Colour Appearance ◽  
Effect Of Light

The higher the colour fidelity of a light source, the lower its luminous efficacy of radiation because the light source spectrum must deviate from V(λ) to deliver the higher fidelity. Two experiments probed the trade-off between energy efficiency and colour quality. Experiment 1 required participants to simultaneously view pairs of light sources differing in colour fidelity, at either a higher (346 lx) or lower (277 lx) illuminance. Participants performed a timed reading task and judged the colour appearance of the pair. There were no effects of illuminance, but larger colour fidelity differences between the light sources in the pair correlated with lower appearance judgements. Experiment 2 simulated the effect of light sources on defined reflectance spectra. The results showed that improvements of colour fidelity above what is often considered satisfactory can yield more satisfying illumination while using the same amount of power.

Comparisons between off-axis detection and on-axis recognition to implement mesopic photometry in roadway lighting standards

2019 ◽  
Vol 52 (4) ◽  
pp. 540-553
Author(s):  
R Ohashi ◽  
Y Akashi ◽  
T Uchida
Keyword(s):  
Peripheral Vision ◽  
Luminance Contrast ◽  
Light Level ◽  
Negative Influence ◽  
Visual Performance ◽  
Light Sources ◽  
Foveal Vision ◽  
Road Lighting ◽  
Light Levels ◽  
Roadway Lighting

Mesopic photometry can be applied to road lighting practice to enhance peripheral visual performance and to reduce light levels. However, mesopic photometry characterizes peripheral vision, whereas photopic photometry characterizes foveal vision at all light levels. Higher scotopic / photopic ( S/ P) ratio light sources which enhance peripheral visual performance may have a negative influence on foveal vision. In addition, light level reductions, as realized in British Standard 5489-1: 2013, may impair foveal visual performance. To investigate the above-described concern, we conducted two experiments. First, we investigated whether Landolt ring targets detected by peripheral vision can be recognized correctly after moving the line of sight to fixate on the targets in foveal vision. Then, we found that subjects could recognize in foveal vision almost all targets that peripheral vision detected. The S/ P ratio of the background lighting did not influence this tendency. Second, we investigated luminance contrast thresholds for foveal vision to compare them with those for peripheral vision, obtained from the first experiment. We found that threshold contrasts of targets recognized by foveal vision were lower than those detected by peripheral vision. These results lead to the conclusion that the use of higher S/ P ratio light sources has no negative influence for foveal vision when implementing mesopic photometry.

Road lighting: A pilot study investigating improvement of visual performance using light sources with a larger gamut area

2020 ◽  
Vol 52 (7) ◽  
pp. 895-905
Author(s):  
B Yang ◽  
M Wei
Keyword(s):  
Pilot Study ◽  
Reaction Times ◽  
Luminance Contrast ◽  
Visual Performance ◽  
Light Sources ◽  
Detection Rates ◽  
Road Lighting ◽  
Colour Contrast ◽  
Gamut Size ◽  
Colour Gamut

Many past studies investigating visual performance focused mainly on the effect of luminance contrast between the target and background. Other studies have suggested the importance of colour contrast on visual performance. This pilot study was designed to investigate whether visual performance in the context of road lighting can be improved by enhancing the chroma of targets. Observers were asked to detect an off-axis target with different levels of luminance, hue, and chroma on a uniform background at 1.5 cd/m2. When the target and the background were set to the same luminance, a zero luminance contrast, the detection rates were significantly lower and the reaction times were significantly longer. Enhancing the colour contrast between the target and the background by increasing the target chroma level, however, was found to improve visual performance to similar levels as those when the target was revealed by luminance contrast against the background. Such an enhancement on colour contrast can be achieved in practice using light sources with a greater colour gamut size.

Experimental Research of Visual Performance with Differenet Optical Spectrum Light Sources

2012 ◽  
Vol 433-440 ◽  
pp. 6375-6383 ◽  
Author(s):  
Yong Hong Yan ◽  
Yang Guan ◽  
G. Lee Tang
Keyword(s):  
Light Source ◽  
Optical Spectrum ◽  
Recognition Rate ◽  
Physiological Effect ◽  
Visual Performance ◽  
Light Sources ◽  
Light Spectrum ◽  
Colour Temperature ◽  
Fluorescent Lamps ◽  
Important Field

In order to determine the effect of different light source’s spectrum to a subjects’ visual performance, this experiment examined three fluorescent lamps with a colour temperature of 2700K, 4000K and 6500K and an incandescent lamp. The results were compared to the average recognition rate a “reference person” from different light sources. Experimental results show significant differences in the recognition rate from different optical spectrum light source and recognition rate value. We determined the best combination of ambient and chalkboard light source and propose avoiding combination for classroom lighting that is clearly inferior. This article provides selection reference for optimal classroom ambient and blackboard lighting. In recent years, the study of psychological and physiological effect of light has become one of the most important field in lighting research[1]. Studies has shown that different light spectrum could affect human circadian rhythm, body temperature and alertness, which directly affecting work efficiency and health[2]. The effects by classroom light spectrum on efficiency and health cannot be ignored, as the students are exposed to one particular lighting environment for extended periods of time. Through a systematic survey of classroom lighting in several universities in Chongqing and Chengdu, T5 fluorescent of high colour temperature about 6500K was the predominant choice for classroom general lighting as well as blackboard lighting. Many students complained that they tired easily at this colour temperature. In another study on classroom light source[3] students’ preference for colour temperature is not fixed but varies according to classroom’s function and illuminance level. It was insufficient to choose colour temperature of classroom lighting based on the results of the above questionnaire. We therefore chose and compared T5 fluorescent lamps of 2700K, 4000K and 6500K colour temperature on the visual performance and their effects on study efficiency, asthenopia and physiological rhythm. Due to space limitations this article only discusses the contrast experiment of visual performance.

Research on Visual Performance under Different Lighting Environments of LED Light Sources

2015 ◽  
Vol 731 ◽  
pp. 92-96
Author(s):  
Yu Liu ◽  
Hong Tao Miao ◽  
Min Huang ◽  
Ai Ping Liu ◽  
Xian Yao Wu
Keyword(s):  
Light Source ◽  
Visual Task ◽  
Visual Performance ◽  
Color Temperature ◽  
Light Sources ◽  
Physiological Changes ◽  
Led Light ◽  
Low Illumination ◽  
Different Color ◽  
The Relationship

In order to study the LED light source illumination and the correlated color temperature effect on the human eye visual performance and physiological changes, through the comparative experiments of visual task performances under the different color temperature (3000K low color temperature, 4000K intermediate color temperature) and the different illumination (1145lux high intensity, 500lux middle intensity, 288lux low illumination), study the relationship between the biological effect and visual performance from two aspects of the visual perception performance and the physical efficiency such as blood pressure and pulse. Research indicates that color temperature 3000K or 4000K, intensity of illumination in about 500lux LED light source is suitable to visual task.

scholarly journals What is the optimal light source for optical mapping using voltage- and calcium-sensitive dyes?

2020 ◽  
pp. 599-607
Author(s):  
V Olejnickova ◽  
D Sedmera
Keyword(s):  
Light Source ◽  
Optical System ◽  
High Speed ◽  
Optical Mapping ◽  
The Other ◽  
Mouse Heart ◽  
Xenon Lamp ◽  
Light Sources ◽  
High Speed Imaging ◽  
Advantages And Disadvantages

Optical mapping is a fluorescence-based physiological method to image spreading of action potential in excitable tissues, such as the heart and central nervous system. Because of the requirements for high speed imaging in low light conditions, highly sensitive high-speed cameras together with an optical system with maximum photon efficiency are required. While the optimization of these two components is relatively straightforward, the choice of the perfect light source is less simple; depending on the other (usually fixed) components, various parameters may acquire different weight in decision-making process. Here we describe the rationale for building an optical mapping setup and consider the relative advantages and disadvantages of three different commonly available light sources: mercury vapor lamp (HBO), xenon lamp (XBO), and light emitting diode (LED). Using the same optical system (fluorescence macroscope) and high-speed camera (Ultima L), we have tested each of the sources for its ability to provide bright and even illumination of the field of view and measured its temporal fluctuations in intensity. Then we used each in the actual optical mapping experiment using isolated, perfused adult mouse heart or chick embryonic heart to determine the actual signal to noise ratio at various acquisition rates. While the LED sources have undergone significant improvements in the recent past, the other alternatives may still surpass them in some parameters, so they may not be the automatic number one choice for every application.

Sign in / Sign up

Export Citation Format

Share Document