Veiling luminance and visual adaptation field in mesopic photometry

2016 ◽  
Vol 49 (6) ◽  
pp. 743-762 ◽  
Author(s):  
M Maksimainen ◽  
M Puolakka ◽  
E Tetri ◽  
L Halonen
Keyword(s):  
Visual Field ◽  
Road Surface ◽  
Visual Adaptation ◽  
High Luminance ◽  
The Road ◽  
Road Lighting ◽  
Average Luminance ◽  
Adaptation State ◽  
Adaptation Field

In mesopic photometry, adaptation luminance is needed to derive the mesopic luminances for the measurement field. The average luminance of the visual adaptation field is considered as the adaptation luminance. The visual adaptation field has yet to be defined in terms of the size, shape, or location within the visual field. A study in three road lighting situations was conducted, in order to determine the feasibility of using the road surface as the adaptation field compared to circular or elliptical adaptation fields. Currently, the road surface is used as the measurement field for calculating road lighting. Using the road surface as the adaptation field resulted in 76–113%, higher average luminance than obtained using circular or elliptical adaptation fields when the road was bordered by a park. High-luminance sources outside of the visual adaptation field cause veiling luminance. Veiling luminance increases the adaptation state, but not the luminance within the measurement field. The bias veiling luminance can cause on mesopic luminance calculations was estimated to be less than 2%. The estimated bias can be considered trivial in practical road lighting measurements.

A new procedure for determining the road surface reduced luminance coefficient table by on-site measurements

2018 ◽  
Vol 51 (1) ◽  
pp. 65-81 ◽  
Author(s):  
N Strbac-Hadzibegovic ◽  
S Strbac-Savic ◽  
M Kostic
Keyword(s):  
Road Surface ◽  
Surface Reflection ◽  
The Road ◽  
Road Lighting ◽  
Average Luminance ◽  
Road Surfaces ◽  
Q Values

Numerous measurements have shown that the standard R classes do not represent adequately many road surfaces used nowadays. Therefore, the construction of portable reflectometers intended for on-site measurements of road surface reflection properties has been given particular attention during the last decade. This paper presents a new procedure for the improvement of the accuracy of such a portable reflectometer. Optimally extrapolating the values of the 20 luminance coefficients (q), each measured by the portable reflectometer for a set of angles of observation (α = 5°–80°), the 20 q-values referring to α = 1° are calculated. This enables their comparison with the corresponding q elements from each of the 447 reduced q-tables derived from the available r-table database, obtained by using a precise laboratory reflectometer on a wide variety of road samples. Selecting the closest reduced q-table, the corresponding r-table and the actual average luminance coefficient can be determined. In order to validate the proposed procedure, which can also be applied to other similar portable reflectometers, measurements of the luminance and overall and longitudinal luminance uniformities were carried out on eleven road-lighting installations. They showed that the results obtained by this procedure deviate only slightly from those obtained using r-tables determined by the laboratory reflectometer.

Simplified field measurement methods for the CIE mesopic photometry system

2016 ◽  
Vol 49 (6) ◽  
pp. 774-787 ◽  
Author(s):  
T Uchida ◽  
Y Ohno
Keyword(s):  
Light Source ◽  
Spectral Reflectance ◽  
Spectral Power ◽  
Road Surface ◽  
Worst Case ◽  
Distribution Method ◽  
The Road ◽  
Reflected Light ◽  
Test Points ◽  
Adaptation Field

For implementation of the mesopic photometry system in CIE 191:2010 to outdoor lighting, two simplified methods to measure the mesopic luminance are proposed. One of the methods, named the Adaptation Spectral Power Distribution) method, assumes that the spectral power distributions (SPDs) of reflected light at test points on the road surface are the same as that of the adaptation field. Another method, named the Source SPD method, assumes that the reflected light SPDs are equal to the SPD of the light source. Error simulations with a real road surface spectral reflectance dataset show that the error distributes over an 8% range due to the variation of the road surface spectral reflectance in the worst case. Although the bias due to the road surface spectral reflectances causes a large error with the Source SPD method, a proposed correction can reduce the error sufficiently. Error simulations also show that the Source SPD method is not so sensitive for lighting scenes that include multiple light source types. It has been shown that the SPD methods can measure the mesopic quantities without scotopic/photopic luminance meters having both V( λ) and V′( λ) detectors when both the adaptation field and test points consist of road surfaces.

Research on the Electrical Energy of Piezoelectric-Embedded Asphalt Mixture

2013 ◽  
Vol 303-306 ◽  
pp. 26-31 ◽  
Author(s):  
Ning Tang ◽  
Chang Jun Sun ◽  
Shao Xu Huang ◽  
Pan Pan ◽  
Shao Peng Wu
Keyword(s):  
Asphalt Concrete ◽  
Road Safety ◽  
Vibrational Energy ◽  
Piezoelectric Materials ◽  
Asphalt Mixture ◽  
Electrical Energy ◽  
Road Surface ◽  
The Road ◽  
Road Lighting ◽  
Road Performance

There is an important effect on road safety with no lighting facilities near the wild road. With the piezoelectric materials embedded in the asphalt concrete as the smart aggregates, the piezoelectric asphalt concrete transforms the vibrational energy of road surface into electrical energy, to supply the road lighting facilities or be stored up. In this study, the electrical energy of piezoelectric-embedded asphalt mixture by using UTM and wheel tester. The results show that PMnS-PZN-PZT ceramic doped with 0.45wt% Fe2O3 (4mm×8pieces) be embedded in the AC-10 asphalt concrete which can obtain well road performance and micropower electrical energy.

Effects of Luminaire Angle and Illumination Topology on Illumination Parameters in Road Lighting

2020 ◽  
pp. 47-56
Author(s):  
Mehmet Sait Cengiz
Keyword(s):  
Road Surface ◽  
Simulation Program ◽  
Horizontal Line ◽  
The Road ◽  
Road Lighting

In this study, refers to two errors in road lighting. It explains the advantages of the staggered layout of luminaires and the problems associated with the use of luminaires located at an angle to the horizontal line of the road. The errors made by the simulation program were proved quantitatively and suggestions for their solution were presented. The loss of luminance of the road surface when illuminated by luminaires located at an angle to the horizontal has been quantitatively proved. In addition, it was found that with the appropriate choice of the layout of luminaires with road lighting, the step between the poles could be reduced by 9.3 %.

INFLUENCE OF ROAD SURFACES ON THE CALCULATION OF A TARGET VISIBILITY TAKING INTO ACCOUNT THE DIRECT AND INDIRECT LIGHTING

2021 ◽  
Author(s):  
L. Lebouc ◽  
V. Boucher ◽  
F. Greffier ◽  
S. Liandrat ◽  
A. Nicolaï ◽  
...  
Keyword(s):  
Road Surface ◽  
Street Lighting ◽  
Target Luminance ◽  
The Road ◽  
Road Lighting ◽  
Road Users ◽  
Road Surfaces ◽  
Indirect Lighting ◽  
On The Road ◽  
Target Visibility

Street lighting ensures visibility and legibility for road users. In this paper, performances of the lighting installation of four road sections with different type of road surface are simulated in accordance with guidelines and road lighting standards. Then, the calculation of the visibility level of a target according to the Adrian’s model is included. Next, the light reflections on the road surface are added to the calculation of the target luminance. For this, the area considered in front of the target as well as the number of elementary surfaces are fixed and a Q_0-scaling of the r-table obtained for α=45° is performed. We compare the results obtained for each section with and without considering the light reflections and conclude that there is negligible incidence of the nature of the road surface on the target luminance. However, an effect of the road surface on the visibility level of the target is observed.

scholarly journals Influence of Pavement Heterogeneity and Observation Angle on Lighting Design: Study with New Metrics

2021 ◽  
Vol 13 (21) ◽  
pp. 11789
Author(s):  
Florian Greffier ◽  
Valérie Muzet ◽  
Vincent Boucher ◽  
Fabrice Fournela ◽  
Laure Lebouc ◽  
...  
Keyword(s):  
Lighting Design ◽  
Observation Angle ◽  
Viewing Angle ◽  
Actual Performance ◽  
The Road ◽  
Road Lighting ◽  
Road Users ◽  
Average Luminance ◽  
Different Types ◽  
Reduce Energy Consumption

Optimization of lighting installations should be a priority in order to reduce energy consumption and obtrusive light while providing optimal visibility conditions for road users. For the design of lighting installations, it is assumed that the road has homogeneous photometric characteristics and only one viewing angle is used. There are often significant differences between the design of lighting installations and their actual performance. In order to examine whether these differences are due to the photometry of the road, this study proposes metrics to assess the influence of road heterogeneity and observation angle. These metrics have been used on many measurements conducted on site and in the laboratory for different pavements. A calculation engine has been developed to realize road lighting design with several r-tables in the same calculation or for different observation angles. Thus, this study shows that a root mean squared deviation (RMSD) calculation, including average luminance and uniformities associated with different r-tables, is directly correlated to a normalized root mean squared deviation (NRMSD) calculation between these r-tables. With these proposed metrics it is possible to optimize lighting installation while taking into account different types of urban surfaces and the diversity of users.

scholarly journals The effect of assuming static or dynamic gaze behaviour on the estimated background luminance of drivers

2018 ◽  
Vol 51 (3) ◽  
pp. 384-401 ◽  
Author(s):  
J Winter ◽  
S Fotios ◽  
S Völker
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Lower Estimate ◽  
Road Surface ◽  
Spatial Sampling ◽  
Background Luminance ◽  
Urban Scenes ◽  
The Road ◽  
Gaze Behaviour ◽  
Visual Gaze

Application of the Commission Internationale de l’Eclairage system for mesopic photometry requires that an estimate is made of the observers’ state of luminance adaptation. This paper addresses an assumption made when estimating background luminance, a component of adaptation luminance. Specifically, using spatial sampling of the visual field we compare background luminances determined from assumptions of static or dynamic visual gaze, the former being a simplification, the latter being a better representation based on eye movements when driving. The comparison was undertaken with luminance images of urban scenes at night on three roads, two real and one simulated. It was found that background luminances were significantly higher when estimated using the dynamic assumption. It was also found that scene luminances at the point of foveal fixations tend to be higher than those luminances influencing peripheral regions of the retina. Compared with the background luminance estimated for a dynamic peripheral field, a horizon-centred 10° circle led to a slightly higher estimate and the road surface luminance to a slightly lower estimate of background luminance.

Measurement of Luminance Coefficients of the Road Pavement for Different Lamp Sources

2013 ◽  
Vol 291-294 ◽  
pp. 2749-2753 ◽  
Author(s):  
Xin Chen ◽  
Chun Hai Wu ◽  
Xiao Dong Zheng
Keyword(s):  
Light Emitting Diode ◽  
Wavelength Region ◽  
Light Sources ◽  
Light Emitting ◽  
The Road ◽  
Road Lighting ◽  
Road Pavement ◽  
Average Luminance ◽  
Sodium Lamp ◽  
High Pressure Sodium Lamp

This paper presents the measurement results of the reduced luminance coefficients of an asphalt pavement sample under three common light sources: high pressure sodium lamp (HPS), metal halide lamp (MH), and light-emitting diode (LED), with a specially designed two-dimensional gonioreflectometer. The relative spectral reflectances are obtained with calculation for three different incident angles which indicate light sources with high output in the long wavelength region may be more effective. The measured average luminance coefficient for HPS and MH are 17% larger than that of LED. It means that LED road lamps need higher illuminance than HPS and MH to realize the same brightness for road lighting.

Tire-Road Interactions — Harmony or Conflict?

1989 ◽  
Vol 17 (1) ◽  
pp. 66-84
Author(s):  
A. R. Williams
Keyword(s):  
Rolling Resistance ◽  
Major Effect ◽  
Road Surface ◽  
Interactive Effects ◽  
Central Theme ◽  
Water Drainage ◽  
The Road ◽  
Truck Tires ◽  
Road Surfaces ◽  
Tire Wear

Abstract This is a summary of work by the author and his colleagues, as well as by others reported in the literature, that demonstrate a need for considering a vehicle, its tires, and the road surface as a system. The central theme is interaction at the footprint, especially that of truck tires. Individual and interactive effects of road and tires are considered under the major topics of road aggregate (macroscopic and microscopic properties), development of a novel road surface, safety, noise, rolling resistance, riding comfort, water drainage by both road and tire, development of tire tread compounds and a proving ground, and influence of tire wear on wet traction. A general conclusion is that road surfaces have both the major effect and the greater potential for improvement.

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