Detection and Identification of Light-Emitting Diode Traffic Signals by Protan Observers

2003 ◽  
Vol 1844 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Michelle Kun Huang ◽  
John D. Bullough ◽  
Peter R. Boyce ◽  
Andrew Bierman
Keyword(s):  
Light Emitting Diode ◽  
Visible Spectrum ◽  
Normal Subjects ◽  
Traffic Signals ◽  
Detection Performance ◽  
Identification Accuracy ◽  
Dominant Wavelength ◽  
Light Emitting ◽  
Red Led ◽  
Color Identification

Protan observers have lower spectral sensitivity than color-normal observers at long wavelengths of the visible spectrum. Responses of protan and color-normal subjects to light emitting diode (LED) and incandescent traffic signals of red and yellow nominal color during simulated daytime viewing conditions are described. Reaction times, missed signal percentages, and color-identification accuracy were measured. The results indicate that for protans, detection performance to red LED signals was enhanced when the dominant wavelength was moved toward shorter wavelengths, but this shift also appeared to decrease their ability to correctly identify the signal color. Although the yellow LED signal used in this study provided similar detection performance for protans as a yellow incandescent signal, its dominant wavelength was sufficiently long for it to sometimes be confused with red. In general, the results of this study are consistent with the 1994 recommendations of the Commission Internationale de l’Éclairage for signal colors to be seen by color-normal and protan observers. Nonetheless, neither detection nor color identification for protans approached that of color-normal observers.

Response to Simulated Traffic Signals Using Light-Emitting Diode and Incandescent Sources

2000 ◽  
Vol 1724 (1) ◽  
pp. 39-46 ◽  
Author(s):  
John D. Bullough ◽  
Peter R. Boyce ◽  
Andrew Bierman ◽  
Kathryn M. Conway ◽  
Kun Huang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Light Emitting Diode ◽  
Reaction Times ◽  
Reaction Time Data ◽  
Traffic Signals ◽  
Time Data ◽  
Light Emitting ◽  
Color Identification ◽  
Mean Reaction Time

Simulated light-emitting diode (LED) traffic signals of different luminances were evaluated relative to incandescent signals of the same nominal color and at the luminances required by the specifications of the Institute of Transportation Engineers. Measurements were made of the reaction times to onset and the number of missed signals for red, yellow, and green incandescent and LED signals. Measurements also were made of subjects’ ability to correctly identify signal colors and of their subjective brightness and conspicuity ratings. All measurements were made under simulated daytime conditions. There were no significant differences in mean reaction time, percentage of missed signals, color identification, or subjective brightness and conspicuity ratings between simulated incandescent and LED signals of the same nominal color and luminance. Higher luminances were needed for the yellow and green signal colors to ensure that they produced the same reaction time, the same percentage of missed signals, and the same rated brightness and conspicuity as a red signal at a given luminance. Equations fitted to the reaction time data, the missed signals data, and the brightness and conspicuity ratings for the LED signals can be used to make quantitative predictions of the consequences of proposed changes in signal luminance for reaction time, brightness, and conspicuity.

Human Factors Impacts of Light-Emitting Diode Airfield Lighting

2017 ◽  
Vol 2626 (1) ◽  
pp. 51-57 ◽  
Author(s):  
John D. Bullough
Keyword(s):  
Human Factors ◽  
Experimental Evidence ◽  
Energy Use ◽  
Light Emitting Diode ◽  
Light Sources ◽  
Light Emitting ◽  
Incandescent Light ◽  
Color Identification ◽  
Lighting Systems ◽  
Maintenance Requirements

Light-emitting diodes (LEDs) differ from incandescent light sources in several ways that are relevant to energy and maintenance requirements of airfield lighting systems. They have higher luminous efficacy and, when designed properly, have longer useful operating lives; both factors make LEDs attractive candidates for airfield lighting. The photometric, colorimetric, and temporal characteristics of LEDs also differ from those of incandescent light sources, and these can have important implications for the appearance of runway and taxiway lighting systems. The present paper reviews publications summarizing experimental and analytical investigations designed to assess these implications with respect to the following human factors impacts: color identification, brightness and glare, visibility in fog and haze, response to onset of flashing lights, and stroboscopic effects such as the phantom array. Overall, this review of experimental evidence suggests that, in addition to their reduced energy use and maintenance requirements, LED airfield lighting can be advantageous in comparison with incandescent lighting systems used to delineate airport runways and taxiways.

scholarly journals Effect of 660 nm Light-Emitting Diode on the Wound Healing in Fibroblast-Like Cell Lines

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Myung-Sun Kim ◽  
Yong-Ick Cho ◽  
Min-Suk Kook ◽  
Sang-Chul Jung ◽  
Young-Hyun Hwang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Wound Healing ◽  
Near Infrared ◽  
Light Emitting Diode ◽  
Biological Effects ◽  
Soft Tissue Injuries ◽  
Light Emitting ◽  
Led Light ◽  
Red Led ◽  
And Migration

Light in the red to near-infrared (NIR) range (630–1000 nm), which is generated using low energy laser or light-emitting diode (LED) arrays, was reported to have a range of beneficial biological effects in many injury models. NIR via a LED is a well-accepted therapeutic tool for the treatment of infected, ischemic, and hypoxic wounds as well as other soft tissue injuries in humans and animals. This study examined the effects of exposure to 660 nm red LED light at intensities of 2.5, 5.5, and 8.5 mW/cm2for 5, 10, and 20 min on wound healing and proliferation in fibroblast-like cells, such as L929 mouse fibroblasts and human gingival fibroblasts (HGF-1). A photo illumination-cell culture system was designed to evaluate the cell proliferation and wound healing of fibroblast-like cells exposed to 600 nm LED light. The cell proliferation was evaluated by MTT assay, and a scratched wound assay was performed to assess the rate of migrating cells and the healing effect. Exposure to the 660 nm red LED resulted in an increase in cell proliferation and migration compared to the control, indicating its potential use as a phototherapeutic agent.

scholarly journals Morphogenetic and physiological effects of LED spectra on the apical buds of Ficus carica var. Black Jack

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ankita Rajendra Parab ◽  
Kho Ying Han ◽  
Bee Lynn Chew ◽  
Sreeramanan Subramaniam
Keyword(s):  
Callus Formation ◽  
Light Emitting Diode ◽  
Multiple Shoots ◽  
Cellular Level ◽  
Ficus Carica ◽  
Light Sources ◽  
Light Emitting ◽  
Apical Buds ◽  
Red Led

AbstractThe use of artificial light sources such as light-emitting diodes (LEDs) has become a prerequisite in tissue culture studies to obtain morphogenetic enhancements on in vitro plants. This technology is essential for developmental enhancements in the growing plant cultures due to its light quality and intensity greatly influencing the in vitro growing explants at a cellular level. The current study investigates the effects of different light-emitting diode (LED) spectra on the growth of apical buds of Ficus carica var. Black Jack. Ficus carica, commonly known as figs is rich in vitamins, minerals, and phytochemicals capable of treating microbial infections and gastric, inflammatory, and cardiac disorders. Apical buds of Ficus carica var. Black Jack, presented morphogenetic changes when grown under six different LED spectra. The highest multiple shoots (1.80 per growing explant) and healthy growing cultures were observed under the blue + red LED spectrum. Wound-induced callus formation was observed on apical buds grown under green LED spectrum and discolouration of the growing shoots were observed on the cultures grown under far-red LED spectrum. Multiple shoots obtained from the blue + red LED treatment were rooted using 8 µM indole-3-acetic acid (IAA), and the rooted plantlets were successfully acclimatised. Compared with the other monochromatic LEDs, blue + red proved to be significantly better for producing excellent plant morphogeny. It is apparent that blue and red LED is the most suitable spectra for the healthy development of plants. The findings have confirmed that the combination of blue + red LED can potentially be used for enhancing growth yields of medicinally and commercially important plants.

scholarly journals Controllable Synthesis of All Inorganic Lead Halide Perovskite Nanocrystals with Various Appearances in Multiligand Reaction System

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1751 ◽  
Author(s):  
Chen Chen ◽  
Louwen Zhang ◽  
Tielin Shi ◽  
Guanglan Liao ◽  
Zirong Tang
Keyword(s):  
Light Emitting Diode ◽  
Dominant Role ◽  
Photophysical Properties ◽  
Reaction System ◽  
Visible Spectrum ◽  
Peanut Oil ◽  
Light Emitting ◽  
Perovskite Nanocrystals ◽  
Halide Perovskite ◽  
Lead Halide

All inorganic cesium lead halide (CsPbX3, X = Cl, Br, I) perovskite nanocrystals (PNCs) exhibit promising applications in light-emitting devices due to their excellent photophysical properties. Herein, we developed a low-cost and convenient method for the preparation of CsPbX3 PNCs in a multiligand-assisted reaction system where peanut oil is applied as a ligand source. The mixed-halide PNCs with tunable optical-band gap were prepared by mixing the single-halide perovskite solutions at room temperature. The resulting PNCs had good monodispersity, with dimensions of 8–10 nm, high photoluminescence quantum yield (96.9%), narrow emission widths (15–34 nm), and tunable emission wavelength (408–694 nm), covering the entire visible spectrum. Additionally, various morphologies of PNCs, such as nanospheres, nanocubes, and nanowires, were obtained by controlling reaction temperature and time, and the amount of oleamine with multiple ligands in peanut oil potentially playing a dominant role in the nucleation/growth processes of our PNCs. Finally, the resulting CsPbBr3 PNCs were employed to develop a white light-emitting diode (WLED), demonstrating the potential lighting applications for our method.

Behavioral response of adult caddisflies (Trichoptera) to blue and green light-emitting diode lamps

Zoosymposia ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 59-62
Author(s):  
GORO KIMURA ◽  
GORO TAJIKA ◽  
TOSHIHIRO KUSAMA ◽  
TSUTOMU TANIKAWA
Keyword(s):  
Uv Light ◽  
Diversity Index ◽  
Light Emitting Diode ◽  
Broad Band ◽  
Green Light ◽  
Visible Spectrum ◽  
Ultraviolet Spectrum ◽  
White Led ◽  
Light Emitting ◽  
Wiener Diversity Index

To clarify the effect of the visible spectrum, we collected Trichoptera adults using blue, green, and white light-emitting diode (LED) lamps and black light (BL) lamps. Except for white LED lamps, all lamps emitted broad-band wavelengths in the ultraviolet spectrum. A total of 212 adult Trichoptera were trapped. The most individuals were attracted by BL (96), followed blue (74), green (32), and white (10). Hydroptilidae spp. was the most abundant taxa among the lamps (183 individuals, 86.3%), followed by Cheumatopsyche brevilineata (23 individuals, 10.8%). Only Hydroptilidae spp. was common to all lamps. The Shannon–Wiener diversity index (H’) was highest at 0.96 for BL, followed by green (0.53), and blue (0.28). Trichoptera were attracted to both UV light and visible light. These results suggest that BL is the most useful for faunistic investigations of Trichoptera.

scholarly journals Towards rare-earth-free white light-emitting diode devices based on the combination of dicyanomethylene and pyranine as organic dyes supported on zinc single-layered hydroxide

2019 ◽  
Vol 10 ◽  
pp. 760-770 ◽  
Author(s):  
Jeff L Nyalosaso ◽  
Rachod Boonsin ◽  
Pierre Vialat ◽  
Damien Boyer ◽  
Geneviève Chadeyron ◽  
...  
Keyword(s):  
White Light ◽  
Fluorescent Dyes ◽  
Light Emission ◽  
Organic Dyes ◽  
Light Emitting Diode ◽  
Composite Films ◽  
Visible Spectrum ◽  
Light Emitting ◽  
Blue Led ◽  
Display Devices

A new luminescent composite film resulting from the dispersion of luminescent organic dyes in a single-layered hydroxide (SLH)-type inorganic matrix has been developed. Two fluorescent organic dyes emitting visible light upon blue LED excitation were investigated in this study: dicyanomethylene (DCM) and pyranine (HPTS). These dyes exhibit broad emission bands that cover a large part of the visible spectrum. The concept developed in our work consisted in keeping SLH in its wet form to ensure a good dispersion of the fluorescent dyes prior to immobilizing the hybrid materials in a silicone polymer to achieve luminescent composite films. We demonstrate that these coatings stacked upon each other and placed above a blue LED lead to white-light emission with suitable photometric parameters for applications in lighting or display devices: colour temperature of 5409 K and colour rendering index (CRI) of 81.

scholarly journals Glare by Light Emitting Diode (LED) vehicle traffic signals

2015 ◽  
Vol 10 (1) ◽  
Author(s):  
Pablo Ixtaina ◽  
Matias Presso ◽  
Nicolás Rosales ◽  
Gustavo H Marin
Keyword(s):  
Light Emitting Diode ◽  
Traffic Signals ◽  
Light Emitting ◽  
Vehicle Traffic
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