VISUAL EFFECTS OF OBJECTS UNDER METAMERISM WITH MULTI-SPECTRAL LIGHT SOURCE

2021 ◽  
Author(s):  
Y.M. Li ◽  
H. Fan ◽  
C.H. Lin ◽  
J.U. Chong ◽  
T.X. Lee
Keyword(s):  
Light Source ◽  
Positive Relationship ◽  
Target Object ◽  
Visual Effects ◽  
Colour Temperature ◽  
Lighting Conditions ◽  
The Future ◽  
Convenience Sampling ◽  
Colour Rendering

This study attempts to simulate the metamerism colour, and the guava was used as the target object. We design four sets of metamers with a correlated colour temperature of 4000K and an illuminance of 750lux. The light source was simulated in the LED cube. The subjects with convenience sampling observed the visual effects, including look delicious, colourful, and colour rendering of guava under metamerism, then analysed its relationship with CRI and CQS. The results showed that colour rendering and visual effects are not a positive relationship, and the effect of CQS is closer to the visual effects of the subjects. The results of this study can be used as a reference for light source lighting designers as a basis for improving lighting conditions. In the future, we can collect databases for the different objects with an optimized multi-spectral light source.

LRT Digest 3: New colour metrics and their use

2019 ◽  
Vol 51 (5) ◽  
pp. 657-681 ◽  
Author(s):  
PR Boyce ◽  
JR Stampfli
Keyword(s):  
Light Source ◽  
Comprehensive Approach ◽  
Source Spectrum ◽  
Light Sources ◽  
Colour Properties ◽  
Executive Summary ◽  
Colour Temperature ◽  
Test Light ◽  
High Level ◽  
Colour Rendering

Executive summary The two metrics traditionally used to quantify the colour properties of light sources are the correlated colour temperature and the CIE General Colour Rendering Index. With the arrival of LEDs as a major light source questions began to be asked about the merits of both of these metrics. The question asked about correlated colour temperature was how far should the chromaticity of a light source be allowed to depart from the Planckian locus before the light emitted could no longer be said to be white? A tolerance to such a departure ( Duv) already existed but now gathered much more attention. The questions asked about the CIE General Colour Rendering Index were more searching. The limitations of the CIE General Colour Rendering Index were explored and, as a result, several alternative approaches to quantifying the colour rendition properties of light sources were proposed. The most comprehensive approach was produced by the Illuminating Engineering Society of North America, first in its Technical Memorandum IES TM-30-15 and more recently in its revision, Technical Memorandum ANSI/IES TM-30-18, which has been accepted as an American Standard. Both these documents describe a system that contains two high-level summary metrics: One for the average fidelity, i.e. how accurately a test light source renders 99 colour samples relative to how they are rendered under a reference illuminant, and the other for the average colourfulness, i.e. the overall increase or decrease in colourfulness of the same colour samples under the same test light source compared to the same reference illuminant. Associated with these overall average metrics are a number of more detailed metrics and graphical presentations. These aim to quantify and illustrate the variations in fidelity and the direction and magnitude of the shifts in chroma and hue around the hue circle. Compared to the CIE General Colour Rendering Index or the CIE Fidelity Index, a metric published by the CIE in 2017, ANSI/IES TM-30-18 provides a more comprehensive approach to quantifying and understanding the effects of light source spectrum on the perception of colour. Unfortunately, the new colour metrics described in IES TM-30-15 and ANSI/IES TM-30-18 have not yet been accepted by the CIE. Despite this, some light source manufacturers have started to provide information on their products expressed in terms of the ANSI/IES TM-30-18 colour metrics and designers are beginning to request them. The expectation is that, eventually, the ANSI/IES TM-30-18 metrics will be adopted by many countries and authorities, because they provide a much more comprehensive description of the colour properties of a light source than the CIE General Colour Rendering Index. This will be of value to light source manufacturers and lighting designers as well as those who prepare lighting codes and guides. It is expected that in the future the minimum set of data considered acceptable for describing the colour properties of a light source are likely to be the correlated colour temperature and the associated Duv value, the CIE Fidelity Index or the matching ANSI/IES TM-30-18 Fidelity Index, together with the ANSI/IES TM-30-18 Gamut Index and the ANSI/IES TM-30-18 Colour Vector Graphic.

Effects of light source spectrum and background colour on the perception of paintings

2019 ◽  
Vol 52 (1) ◽  
pp. 36-63
Author(s):  
L Bellia ◽  
F Fragliasso ◽  
E Stefanizzi
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Source Spectrum ◽  
Light Emitting ◽  
Colour Temperature ◽  
Test Room ◽  
Led Light ◽  
Lighting Conditions ◽  
Set Up ◽  
Effect Of Light

This paper presents an experiment on the effect of light on the perception of paintings. The experiment was performed in a test-room where a typical museum exhibition set-up was simulated. Two different paintings were shown to 44 participants, under different light scenes obtained by using tuneable LED (Light Emitting Diode) wallwashers. To set the light scenes, the following parameters were modified: correlated colour temperature of the lighting, illuminance on the painting and the colour of the background wall. Participants answered a questionnaire to assess the perception of the paintings’ colours, the lighting conditions and the pleasantness of the exhibition set-up. The results demonstrated that illuminance is the parameter mainly affecting perception, for both paintings. However, correlated colour temperature and wall colour, as well as the combination of the three different considered parameters, can more or less influence perception depending on the chromatic composition of the painting.

scholarly journals Influence of Peak Wavelengths on Properties of Mixed-LED White-Light Sources

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Snjezana Soltic ◽  
Andrew N. Chalmers
Keyword(s):  
Light Source ◽  
White Light ◽  
Light Sources ◽  
Peak Wavelength ◽  
White Light Source ◽  
Luminous Efficacy ◽  
Colour Temperature ◽  
Colour Rendering

The purpose of this investigation is to quantify the influence of the peak wavelength shifts in commercially available LEDs on the characteristics of the mixed-LED white-light sources. For this purpose, a tetrachromatic spectrum was optimized and then subjected to deviations in the peak wavelengths. A total of 882 combinations of peak wavelength values were evaluated, and the results are reported in terms of correlated colour temperature, colour-rendering properties, and radiant luminous efficacy. The results show that there can be significant changes in the characteristics of the source under these conditions. Such changes are highly likely to present problems when dealing with applications where an effective and accurate white-light source is important.

Influence of the perceived size of a light source on non-visual effects in humans

2020 ◽  
Vol 9 (6) ◽  
pp. 385-393
Author(s):  
Arvid Niemeyer ◽  
Lucia Rottmair ◽  
Cornelius Neumann ◽  
Cornelius Möckel
Keyword(s):  
Working Memory ◽  
Light Exposure ◽  
Error Rates ◽  
Positive Contribution ◽  
Measurement Point ◽  
Visual Effects ◽  
Lighting Conditions ◽  
Light Measurement ◽  
And Performance ◽  
Main Effects

AbstractLight not only enables humans to perceive their surroundings, but also influences their sleep–wake cycle, mood, concentration and performance. Targeted use of these so called nonvisual effects could also have a positive contribution in automobiles by keeping passengers alert, minimizing error rates or bootsting attention in general. Since construction space in vehicle interios is scarce, this study compared the influence of differently-sized light panels and thus solid angles on nonvisual effects. In a counterbalanced order, 32 volunteers were exposed to three lighting conditions in the morning: baseline (12 lx, 2200 K), small (200 lx, 6500 K, 0.05 sr) and large (200 lx, 6500 K, 0.44 sr). During each session of 60 min, alertness, concentration and working memory were assessed before and during light exposure. After data analysis no significant main effects of light, measurement point or interaction between light and measurement point could be seen.

scholarly journals Towards the Optimum Light Source Spectrum

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Andrew Chalmers ◽  
Snjezana Soltic
Keyword(s):  
Light Source ◽  
Large Scale ◽  
Source Spectrum ◽  
Light Sources ◽  
Luminous Efficacy ◽  
Light Emitting ◽  
Spectral Bands ◽  
Good Energy ◽  
Lighting Systems ◽  
Colour Rendering

This paper is concerned with designing light source spectra for optimum luminous efficacy and colour rendering. We demonstrate that it is possible to design light sources that can provide both good colour rendering and high luminous efficacy by combining the outputs of a number of narrowband spectral constituents. Also, the achievable results depend on the numbers and wavelengths of the different spectral bands utilized in the mixture. Practical realization of these concepts has been demonstrated in this pilot study which combines a number of simulations with tests using real LEDs (light emitting diodes). Such sources are capable of providing highly efficient lighting systems with good energy conservation potential. Further research is underway to investigate the practicalities of our proposals in relation to large-scale light source production.

scholarly journals The optimum colour temperature for illumination of Japanese-style gardens in summer and winter

2017 ◽  
Vol 51 (1) ◽  
pp. 82-98 ◽  
Author(s):  
D Jia ◽  
T Misawa ◽  
M Takamatsu ◽  
S Hirobayashi
Keyword(s):  
Light Source ◽  
Image Recognition ◽  
Statistical Significance ◽  
Semantic Differential ◽  
Cultural Value ◽  
Evaluation Methodology ◽  
Colour Temperature ◽  
Differential Technique ◽  
Vegetation Water ◽  
Semantic Differential Technique

Japanese-style gardens offer a wealth of spiritual and cultural value. In this study, we attempt to determine the optimum colour temperature for lighting Japanese-style gardens at night. We analyse the influence of a change in light source colour temperature on image recognition using digitalization and quantification with the semantic differential technique. In addition, we propose a new evaluation methodology for the semantic differential technique and examine the statistical significance of the results. We find that in summer, impressions of the optimum colour temperature for each element (vegetation, water, stone and structure) differ significantly, but in winter, because of the effects of snow, differences in the impression of each colour temperature are not as distinct. Moreover, the colour of the natural environment or overall season affects peoples’ preferred light source colour temperature.

Research Note: LED chip-on-board packaging technology for strict colour tolerance

2017 ◽  
Vol 49 (8) ◽  
pp. 1052-1057
Author(s):  
J Zhang ◽  
P Ge ◽  
Z Zhou ◽  
D Liu ◽  
H Wang ◽  
...  
Keyword(s):  
Research Note ◽  
Luminous Efficacy ◽  
Packaging Technology ◽  
Colour Temperature ◽  
Colour Rendering ◽  
Method Show

In the field of LED packaging, people usually pay more attention to colour temperature, luminous efficacy and colour rendering than colour tolerance. This paper focuses on how to meet strict colour tolerances in the process of chip-on-board packaging. The McAdam ellipses are used to explain the meaning of colour tolerance. A method based on adjusting the amount of phosphor glue and the proportions of different phosphors it contains is described. Measurements on samples packaged according to this method show that it makes it possible to meet strict colour tolerance requirements.

scholarly journals ANALISIS PENGARUH PENGETAHUAN PERPAJAKAN, SOSIALISASI, PELAYANAN, SANKSI PERPAJAKAN, DAN TINGKAT PENDIDIKAN WAJIB PAJAK TERHADAP KESADARAN WAJIB PAJAK MEMBAYAR PBB P2

2020 ◽  
Vol 6 (1) ◽  
pp. 75-95
Author(s):  
Yunita Isna Ratri ◽  
Achmad Tjahjono
Keyword(s):  
Linear Regression ◽  
Multiple Linear Regression ◽  
Sampling Method ◽  
Positive Relationship ◽  
Secondary Data ◽  
Education Level ◽  
Primary Data ◽  
Partial Knowledge ◽  
Convenience Sampling

The Analysis Influence of Knowledge Taxation, Socialization, Service, Tax Sanctions and Education Level of Taxpayer Awareness Paying PBB P2. SkripsiStarta One (S1) Accounting Departement STIE Widya Wiwaha Yogyakarta 2018. The purpose of this research is to know influence of Knowledge Taxation,Socialization, Service, Tax Sanctions and Education Level of Taxpayer Awareness Paying PBB P2 with using multiple linear regression and dummy’s variable. The sample in this research includes 120 respondences who are in the District of Prambanan, village Bokoharjo, Madurejo, Sambirejo, Sumberharjo, Wukirharjo, Gayamharjo. The sampling method is convenience sampling. The collected of data to use primary data with questionnaire technique and secondary data that is data taken from DPPKAD (Dinas Pendapatan Pengelolaan Keuangan Aset Daerah). The results of the research to drawn that the partial, knowledge taxation has a positive relationship and significantly influence the awareness of paying taxpayers PBB P2, and Services have a positive relationship and significant effect on the awareness of paying taxpayers PBB P2. By mutual independentvariables affect the awareness of paying taxpayers PBB P2 as a dependent variable.

Effect Of Chromaticity Of Surrounding Light Sources on Mesopic Adaptation Luminance

2021 ◽  
pp. 30-38
Author(s):  
Sangita Sahana ◽  
Biswanath Roy
Keyword(s):  
Light Source ◽  
The State ◽  
Light Sources ◽  
Ambient Light ◽  
Lighting Conditions

This paper presents variations in mesopic adaptation luminance in the presence of ambient light sources along with main light source for outdoor lighting applications. Mesopic photometry system is based on peripheral task, and adaptation luminance is required to compute the effective mesopic radiance for the measured area. Different lighting conditions were considered to determine the effect of chromaticity of bright surrounding sources other than the main light sources to the state of observer adaptation. The veiling luminance caused by the surrounding sources increases the state of observer adaptation, but not the luminance within the measurement field. It has also been observed that in case of cool white surrounding sources, adaptation luminance increases significantly than that of warm white sources.

Four minutes might not be enough for light colour temperature to affect sleepiness, mental effort, and light ratings

2018 ◽  
Vol 51 (7) ◽  
pp. 1128-1138
Author(s):  
R Lasauskaite ◽  
EM Hazelhoff ◽  
C Cajochen
Keyword(s):  
Task Performance ◽  
Cardiovascular Response ◽  
Cognitive Task ◽  
Memory Task ◽  
Subjective Ratings ◽  
Night Time ◽  
Colour Temperature ◽  
Lighting Conditions ◽  
Effort Mobilization ◽  
Short Memory

Light exerts a number of non-image-forming effects that are mostly apparent during night-time but can also been seen during daytime. Recently, we have shown that exposure to light of higher colour temperature prior to performing a cognitive task leads to a weaker effort-related cardiovascular response compared to exposure to light of lower colour temperature. This present study tested if presenting light of different colour temperatures during rather than before the task performance would lead to equivalent changes in effort mobilization. Participants performed a modified Sternberg short-memory task for eight minutes as lighting conditions were adjusted to one of four experimental lighting conditions (2800 K, 4000 K, 5000 K, or 6500 K) after the first four minutes, for the remaining four minutes. We predicted that effort-related cardiovascular response would strengthen with decreasing colour temperature. The results, however, did not follow this predicted pattern. No significant effects of lighting conditions on subjective measures were observed. Therefore, we conclude that four minutes might not be enough for light colour temperature to induce changes in effort-related cardiovascular response or affect subjective ratings of sleepiness and lighting.

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