Influence of Light Source and Cathodoluminescence on the Color Parameters of Ruby Red

2011 ◽  
Vol 492 ◽  
pp. 379-383 ◽  
Author(s):  
Xiang Li ◽  
Ying Guo
Keyword(s):  
Light Source ◽  
Power Distribution ◽  
Light Sources ◽  
Visual Appearance ◽  
Color Parameters ◽  
Red Color ◽  
Strong Luminescence ◽  
Hue Angle ◽  
The Impact ◽  
Sun Light

According to different light sources and cathodoluminescence (CL) intensity, the performance of color parameters (lightness L*, chromaticity a* and b*, chroma C*, hue angle ho) and chromophore contents (Cr3+, åFe) are studied to analyze the impact of all these elements on ruby red color. Ruby red under the standard light source D65 (a*=5.65 ~ 26.97, b*= -5.43~3.98) is similar with the color under natural sun-light. Purplish red ho Î (354.14°, 0.7°) with medium-low lightness (L*= 32 ~ 40) under D65 displays the best visual appearance, showing a relatively high value. Comparing with D65, standard light source A reveals ruby a deep red hue (a*= 10.61 ~ 37.39, b*= -6.59 ~ 7.50). Because of the strongest spectrum power distribution in the orange range and fluorescence of light source U30, the hue of orangish tone is mixed in ruby red (a*= 6.92 ~ 31.23, b*= 0.31 ~ 9.34). It is illustrated that åFe can inhibit the intensity of CL which is compared in different voltages. Low lightness purplish red is easy to be influenced by CL and always shows strong luminescence correspondingly. It is concluded that ruby purplish red has strong luminescence of CL which is usually supported by a few of åFe and medium-low lightness under D65, which has an excellent visual perception.

AN OVERVIEW OF THE IMPACT OF STRAY LIGHT FROM COMMERCIAL GREENHOUSES

2021 ◽  
Author(s):  
K. Bertin ◽  
G. Zissis ◽  
G. Salas ◽  
P.M. Raynham ◽  
A. Moutsi ◽  
...  
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Stray Light ◽  
Significant Problem ◽  
Light Sources ◽  
Spectral Power Distribution ◽  
Outdoor Work ◽  
Local Residents ◽  
The Impact ◽  
Current Standards

Stray light from commercial greenhouses is becoming a significant problem causing disruption to wildlife activity and annoyance for local residents. To quantify the amount of stray light from a typical large greenhouse the authors have modelled several lighting installations based on a range of generic horticultural light sources. The impact of the stray light is dependent on the spectral power distribution of the sources employed, the intensity and distribution. Current standards for obtrusive light from outdoor work places do not seem to be suitable when applied to greenhouses.

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.

scholarly journals Monochromatic light-emitting diode (LED) source in layers hens during the second production cycle

2015 ◽  
Vol 19 (9) ◽  
pp. 877-881 ◽  
Author(s):  
Rodrigo Borille ◽  
Rodrigo G. Garcia ◽  
Irenilza A. Nääs ◽  
Fabiana R. Caldara ◽  
Mayara R. Santana
Keyword(s):  
Light Source ◽  
Laying Hens ◽  
Egg Quality ◽  
Monochromatic Light ◽  
Latin Square ◽  
Continuous Illumination ◽  
Production Cycle ◽  
Light Sources ◽  
Light Regimen ◽  
The Impact

ABSTRACTLight is an important environmental factor for birds, allowing not only their vision, but also influencing their physiological responses, such as behavioral and reproductive activity. The objective of this experiment was to evaluate the impact of different colors of monochromatic light (LED) sources in laying hens production during the second laying cycle. The study was conducted in an experimental laying house during 70 days. A total of 300 laying hens Isa Brown® genetic strain, aged 95 weeks, in the second laying cycle were used in the study. The artificial light sources used were blue, yellow, green, red and white. The light regimen was continuous illumination of 17 h per day (12 h natural and 5 h artificial) in a daily light regimen of 17L:5D (light: dark). The Latin Square design was adopted with five treatments (five colors) divided into five periods, and five boxes, with six replicates of ten birds in each box. The production and egg quality were evaluated. The different colors of light source did not affect production parameters or egg quality (p > 0.05). The monochromatic light source may be considered as an alternative to artificial lighting in laying hens during the second production cycle.

scholarly journals Seven Different Lighting Conditions in Photogrammetric Studies of a 3D Urban Mock-Up

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8002
Author(s):  
Katarzyna Bobkowska ◽  
Pawel Burdziakowski ◽  
Jakub Szulwic ◽  
Karolina M. Zielinska-Dabkowska
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Total Error ◽  
Spectral Characteristics ◽  
Point Clouds ◽  
Light Sources ◽  
Experimental Proof ◽  
Lighting Conditions ◽  
The Impact

One of the most important elements during photogrammetric studies is the appropriate lighting of the object or area under investigation. Nevertheless, the concept of “adequate lighting” is relative. Therefore, we have attempted, based on experimental proof of concept (technology readiness level—TRL3), to verify the impact of various types of lighting emitted by LED light sources for scene illumination and their direct influence on the quality of the photogrammetric study of a 3D urban mock-up. An important issue in this study was the measurement and evaluation of the artificial light sources used, based on illuminance (E), correlated colour temperature (CCT), colour rendering index (CRI) and Spectral power distribution (SPD) and the evaluation of the obtained point clouds (seven photogrammetric products of the same object, developed for seven different lighting conditions). The general values of the quality of the photogrammetric studies were compared. Additionally, we determined seventeen features concerning the group of tie-points in the vicinity of each F-point and the type of study. The acquired traits were related to the number of tie-points in the vicinity, their luminosities and spectral characteristics for each of the colours (red, green, blue). The dependencies between the identified features and the obtained XYZ total error were verified, and the possibility of detecting F-points depending on their luminosity was also analysed. The obtained results can be important in the process of developing a photogrammetric method of urban lighting monitoring or in selecting additional lighting for objects that are the subject of a short-range photogrammetric study.

Spectral Estimation of Multiple Light Sources based on Highlight Detection

2020 ◽  
Vol 64 (5) ◽  
pp. 50408-1-50408-9
Author(s):  
Shoji Tominaga ◽  
Keita Hirai ◽  
Takahiko Horiuchi
Keyword(s):  
Light Source ◽  
Power Distribution ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Spectral Estimation ◽  
Spectral Composition ◽  
Image Data ◽  
Light Sources ◽  
Relaxation Labeling ◽  
Highlight Detection

Abstract The authors discuss the spectral estimation of multiple light sources from image data in a complex illumination environment. An approach is proposed to effectively estimate illuminant spectra and the corresponding light sources based on highlight areas that appear on dielectric object surfaces. First, the authors develop a highlight detection method using two types of convolution filters with Gaussian distributions, center-surround and low-pass filters. This method is available even for white surfaces, and it is independent of object color and of viewing and incidence angles. Second, they present an algorithm for estimating the illuminant spectra from extracted highlight areas. Each specular highlight area has a spectral composition corresponding to only one light source among multiple light sources. The spectral image data are projected onto a two-dimensional subspace, where a linear cluster in pixel distribution is detected for each highlight area. Third, the relative positional relationship between highlight areas among different object surfaces is used to identify the light sources on each surface. The authors develop an algorithm based on probabilistic relaxation labeling. The light source for each highlight and the corresponding spectral-power distribution are determined from the iterative labeling process. Finally, the feasibility of the proposed approach is examined in an experiment using a real complex environment, where dielectric objects are illuminated by multiple light sources of light-emitting diode, fluorescence, and incandescence.

The Influences of Lightness Variation of the Non-Color Background on the Color of the Blood Amber

2014 ◽  
Vol 633 ◽  
pp. 524-535
Author(s):  
Ya Xiao ◽  
Ying Guo ◽  
Da Peng Chen
Keyword(s):  
Color Space ◽  
Measurement Instrument ◽  
Color Difference ◽  
High Brightness ◽  
Color Parameters ◽  
Color Saturation ◽  
Red Color ◽  
Hue Angle ◽  
Color Background ◽  
The One

In this study, based on CIE L*a*b* uniform color space, the Color i5 measurement instrument was used to measure the color parameters of seven blood amber samples under the D65 illuminant. In addition, the influences of lightness variation of the non-color background on the lightness, the color saturation and the hue of the blood amber were also investigated and discussed. The results show that the lightness of the blood amber is significantly enhanced with the increased lightness of the non-color background and the blood amber with higher transparency is more sensitive to the change of the non-color background; the color saturation of the blood amber increases gradually with the raise of the lightness of the non-color background, which means that the blood amber on the high-lightness background looks more bright-colored than the one on the low-lightness background; the red color hue angle range of blood amber turns out to be diffusing with the increase of the lightness of the non-color background, which means that a slight difference of the hue can be more easily discriminated on the high-brightness background. Thus, it can be concluded that the blood amber with higher transparency is much easier to be influenced by the non-color background; and the increase of the lightness of the non-color background can lead to higher lightness, more bright-colored saturation and diffused hue angle range of the blood amber; and the blood amber is more bright-colored and the color difference can be more easily discriminated on the background with higher lightness.

scholarly journals Accuracy of the GENEActiv Device for Measuring Light Exposure in Sleep and Circadian Research

2020 ◽  
Vol 2 (2) ◽  
pp. 143-152
Author(s):  
Julia E. Stone ◽  
Elise M. McGlashan ◽  
Elise R. Facer-Childs ◽  
Sean W. Cain ◽  
Andrew J. K. Phillips
Keyword(s):  
Light Source ◽  
Light Exposure ◽  
Red Light ◽  
Spectral Composition ◽  
Green Light ◽  
Well Being ◽  
Infrared Light ◽  
Light Sources ◽  
Lower Accuracy ◽  
The Impact

Light is a variable of key interest in circadian rhythms research, commonly measured using wrist-worn sensors. The GENEActiv Original is a cost-effective and practical option for assessing light in ambulatory settings. With increasing research on health and well-being incorporating sleep and circadian factors, the validity of wearable devices for assessing light environments needs to be evaluated. In this study, we tested the accuracy of the GENEActiv Original devices (n = 10) for recording light under a range of ecologically relevant lighting conditions, including LED, fluorescent, infrared, and outdoor lighting. The GENEActiv output had a strong linear relationship with photopic illuminance. However, the devices consistently under-reported photopic illuminance, especially below 100 lux. Accuracy below 100 lux depended on the light source, with lower accuracy and higher variability under fluorescent lighting. The device’s accuracy was also tested using light sources of varying spectral composition, which indicated that the device tends to under-report photopic illuminance for green light sources and over-report for red light sources. Furthermore, measures of photopic illuminance were impacted by infrared light exposure. We conclude that the GENEActiv Original is suitable for mapping light patterns within an individual context, and can reasonably differentiate indoor vs. outdoor lighting, though the accuracy is variable at low light conditions. Given the human circadian system’s high sensitivity to light levels below 100 lux, if using the GENEActiv Original, we recommend also collecting light source data to better understand the impact on the circadian system, especially where participants spend prolonged periods in dim lighting.

scholarly journals Colour Quality Evaluation of Bluish-Green Serpentinite Based on the CIECAM16 Model

Minerals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 38
Author(s):  
Zitong Zhao ◽  
Ying Guo
Keyword(s):  
Light Source ◽  
Vision System ◽  
Appearance Model ◽  
Light Sources ◽  
Bluish Green ◽  
Hue Angle ◽  
Tristimulus Values ◽  
High Prediction ◽  
Colour Appearance

The CIECAM16 colour appearance model is currently a model with high prediction accuracy. It can solve the problem of predicting the influence of different observation conditions on the colour of gemstones. In this study, a computer vision system (CVS) was used to measure the colour of 59 bluish-green serpentinite samples, and the tristimulus values were input into the CIECAM16 forward model to calculate the colour appearance parameters of serpentinite under different surrounds, illuminances, and light sources. It was found that the darkening of the surround causes the lightness and brightness to increase. Pearson’s r of brightness and colourfulness with illuminance is 0.885 and 0.332, respectively, which predicts the Stevens and Hunt effects. When the light source changes from D65 to A, the calculated hue angle shifts to the complementary area of the A light source, which is contrary to the CVS measurement result. The D65 light source is more suitable for the colour presentation and classification of bluish-green serpentinite.

Smartphone-based measurement of the melanopic daylight efficacy ratio

2019 ◽  
Vol 2019 (1) ◽  
pp. 344-348
Author(s):  
Marcel Lucassen ◽  
Dragan Sekulovski ◽  
Tobias Borra
Keyword(s):  
Circadian Rhythm ◽  
Light Source ◽  
Power Distribution ◽  
General Public ◽  
Spectral Power ◽  
Spectral Power Distribution ◽  
Camera Parameters ◽  
The Absolute ◽  
The Impact

Recently, the CIE published a new standard in which the so called 'melanopic daylight efficacy ratio' (abbreviated to melanopic DER) is introduced. This number is helpful in estimating the impact that a light source may have on our circadian rhythm. Although the melanopic DER can be directly calculated from the spectral power distribution, in case the latter is unknown a spectrophotometer or similar instrument is required, which is usually unavailable to the general public. Here we demonstrate how the melanopic DER can be accurately estimated from a smartphone image of two selected color samples. In addition, using the smartphone's camera parameters we provide a method to estimate the illuminance. Combined these measurements allow an evaluation of the absolute melanopic stimulation.

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