Optimising Light Source Spectrum For Object Reflectance

2014 ◽  
Author(s):  
Dorukalp Durmus ◽  
Wendy Davis
Keyword(s):  
Light Source ◽  
Source Spectrum

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 Optimization of LED Lighting for Clinical Settings

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Snjezana Soltic ◽  
Andrew Chalmers
Keyword(s):  
Light Source ◽  
Performance Criteria ◽  
Source Spectrum ◽  
Clinical Settings ◽  
Colour Properties ◽  
Led Lighting ◽  
Led Light ◽  
De Algorithm ◽  
Lighting Systems ◽  
Spectral Design

The advent of the LED light source has promoted the concept of human-centric lighting (HCL). The LED has also been responsible for increases in the electrical efficiency of lighting systems, coupled with recent improvements in their colour properties. We have found that it is also possible to create a lit environment with enhanced clinical attributes by providing a source spectrum that meets the requirements of the Cyanosis Observation Index (COI). This paper describes the use of a differential evolution (DE) algorithm for the spectral design of a mixed LED light source capable of meeting COI recommendations as well as HCL performance criteria.

Spontaneous assembly and synchronous scan spectra of gold nanoparticle monolayer Janus film with thiol-terminated polystyrene

RSC Advances ◽  
2014 ◽  
Vol 4 (101) ◽  
pp. 57611-57614 ◽  
Author(s):  
Yunbo Li ◽  
Linlin Song ◽  
Yisha Qiao
Keyword(s):  
Metal Nanoparticles ◽  
Gold Nanoparticle ◽  
Light Source ◽  
Source Spectrum ◽  
Synchronous Scan ◽  
Nanoparticle Film

This communication presents a facile method for preparing ordered hydrophilic metal nanoparticles into gold nanoparticle monolayer Janus film. It also reveals the enhanced light source spectrum properties of the gold nanoparticle film.

Light Source Spectrum Strongly Influences the In Vitro Estimation of Sun Protection Factor

2012 ◽  
Vol 88 (4) ◽  
pp. 1005-1011 ◽  
Author(s):  
Yoshimasa Miura ◽  
Sayaka Suzuki ◽  
Tetsuji Hirao ◽  
Masato Hatao
Keyword(s):  
Light Source ◽  
Sun Protection ◽  
Source Spectrum ◽  
Protection Factor ◽  
Sun Protection Factor

scholarly journals Photopolymerization of dental materials: Types and characteristics of the light sources

2009 ◽  
Vol 56 (4) ◽  
pp. 207-212 ◽  
Author(s):  
Gorjana Popovic ◽  
Roze Djokic
Keyword(s):  
Absorption Spectrum ◽  
Light Source ◽  
Uv Light ◽  
Dental Materials ◽  
Life Time ◽  
Source Spectrum ◽  
Light Sources ◽  
Light Spectrum ◽  
Visible Part ◽  
Short Time

Light from the polymerization source which initiates photopolymerization in the material has its determined wavelength. Photoinitiator, such as camphorhinone, excited by light, can be activated with any of the wavelength from its absorption spectrum. To obtain successful photopolymerization, light source should emit waves of adequate wavelength; light intensity has to be optimal, to have sufficient time of exposure and material up to 2 mm thickness. Photoinitiator inside the material should match light source spectrum and work regime. Halogen lamps have wide spectra of wavelengths in the visible part of the light spectrum. Their spectra are similar to absorption spectrum of camphorhinone. Plasma (xenon) lamps emit blue light. Though their diapason is low, spectra have great intensity. Adequate diapason and easy excitation allow them to have short time of exposure. LED lamps have blue diodes as light source. They do not need filters due to narrow emission spectrum. Laser (argon) lamps are the only that emit linear spectra. Ultraviolet (mercury) lamps are not in use any more in dentistry; theirs initiators were activated by UV light. LED lamps have longer life time; do not change the spectra during time, warm less, do not need filters, allow change of the source for more powerful, more efficient and more advantageous two steps or impulse illumination mode. However, LED lamps can not be used for a material that has photoinitiator(s) activated by light with wavelength above the maximum of the LED spectra.

scholarly journals Energy-Saving Light Source Spectrum Optimization by Considering Object's Reflectance

2017 ◽  
Vol 9 (2) ◽  
pp. 1-11 ◽  
Author(s):  
Jingjing Zhang ◽  
Run Hu ◽  
Bin Xie ◽  
Xingjian Yu ◽  
Xiaobing Luo ◽  
...  
Keyword(s):  
Energy Saving ◽  
Light Source ◽  
Source Spectrum ◽  
Spectrum Optimization

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.

scholarly journals Appearance of Achromatic Colors Under Optimized Light Source Spectrum

2018 ◽  
Vol 10 (6) ◽  
pp. 1-11 ◽  
Author(s):  
Dorukalp Durmus ◽  
Wendy Davis
Keyword(s):  
Light Source ◽  
Source Spectrum

scholarly journals An Improved Impact Source Locating System Using FBG Rosette Array

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3453
Author(s):  
Chen ◽  
Shin
Keyword(s):  
Light Source ◽  
Signal To Noise Ratio ◽  
Fold Increase ◽  
Fiber Axis ◽  
Source Spectrum ◽  
Directional Sensitivity ◽  
Signal To Noise ◽  
Location Accuracy ◽  
System Sensitivity ◽  
Noise Ratio

For structures vulnerable to foreign object impact damages, it would be desirable to detect and locate any occurrence of such impacts. This can be achieved by monitoring the stress waves generated by an impact together with certain source localization algorithms. Being small, electromagnetic influence immune and durable, Fiber Bragg grating (FBG) sensors are advantageous for this task. One drawback of FBGs for this purpose is their uneven directional sensitivity, which limits its localization ability to within 50° on either side of the fiber axis. Beyond this range, the signal is too weak and masked by noises and the location errors increase abruptly. Two approaches have been tested on a 0.8 m × 0.8 m × 6 mm plate for possible improvement on the system accuracy: firstly, an interrogation scheme with stronger light source intensity and steeper edge filter is employed to enhance the signal-to-noise ratio and system sensitivity; secondly, rosettes with two orthogonal FBGs are cascaded together to replace single FBGs to alleviate the directional sensitivity problem. It was found that a four-fold increase in signal to noise ratio contributed by stronger light source does improve the location accuracy, but only marginally. For the rosette approach, the relative positions of the Bragg wavelength of the FBGs and the light source spectrum are crucial to accuracy. Three different wavelength configurations have been tested and the reasons for their success or failure are discussed. It was shown that with an optimal wavelength configuration, the rosette array can virtually extend the good location accuracy to all over the plate.

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