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.

COLOUR FIDELITY AND ILLUMINANCE TRADE-OFF: TESTING LIGHTING VALUES

2021 ◽  
Author(s):  
J.A. Veitch ◽  
L.A. Whitehead
Keyword(s):  
Energy Efficiency ◽  
Light Source ◽  
Reflectance Spectra ◽  
Source Spectrum ◽  
Light Sources ◽  
Trade Off ◽  
Luminous Efficacy ◽  
Reading Task ◽  
Colour Appearance ◽  
Effect Of Light

The higher the colour fidelity of a light source, the lower its luminous efficacy of radiation because the light source spectrum must deviate from V(λ) to deliver the higher fidelity. Two experiments probed the trade-off between energy efficiency and colour quality. Experiment 1 required participants to simultaneously view pairs of light sources differing in colour fidelity, at either a higher (346 lx) or lower (277 lx) illuminance. Participants performed a timed reading task and judged the colour appearance of the pair. There were no effects of illuminance, but larger colour fidelity differences between the light sources in the pair correlated with lower appearance judgements. Experiment 2 simulated the effect of light sources on defined reflectance spectra. The results showed that improvements of colour fidelity above what is often considered satisfactory can yield more satisfying illumination while using the same amount of power.

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.

Reducing the Optical Noise of Machine Vision Optical Scanners for Landslide Monitoring

2021 ◽  
pp. 103-133
Author(s):  
Jesús Elias Miranda-Vega ◽  
Javier Rivera-Castillo ◽  
Moisés Rivas-López ◽  
Wendy Flores-Fuentes ◽  
Oleg Sergiyenko ◽  
...  
Keyword(s):  
Light Source ◽  
Source Monitoring ◽  
Vision System ◽  
Moving Average ◽  
Median Filter ◽  
Landslide Monitoring ◽  
Light Sources ◽  
Optical Noise ◽  
Optical Scanners ◽  
Optical Scanner

An application of landslide monitoring using optical scanner as vision system is presented. The method involves finding the position of non-coherent light sources located at strategic points susceptible to landslides. The position of the light source is monitored by measuring its coordinates using a scanner based on a 45° sloping surface cylindrical mirror. This chapter shows experiments of position light source monitoring in laboratory environment. This work also provides improvements for the optical scanner by using digital filter to smooth the opto-electronic signal captured from a real environment. The results of these experiments were satisfactory by implementing the moving average filter and median filter.

Influence of Light, Distance and Size on Recognition and Classification of Food Grains' Images

2010 ◽  
Vol 6 (2) ◽  
Author(s):  
Basavaraj S Anami ◽  
Dayanand G Savakar
Keyword(s):  
Minimum Distance ◽  
Vision System ◽  
Image Acquisition ◽  
Human Vision ◽  
Light Sources ◽  
Lighting Condition ◽  
Natural Lighting ◽  
Food Grains ◽  
Food Grain

The paper presents an artificial neural network based approach to corroborate the effect of variations in illumination, distance of image acquisition and size on recognition and classification accuracies of bulk food grain image samples. Different food grains samples like Wheat, Groundnut, Green gram and Jowar are considered. The image samples are taken by varying acquisition distances, illumination and sizes. The natural light source and the minimum distance of 40 centimeters are ideal for image acquisition compared to other light sources and varying distance of image acquisition. The experimental results have shown a reduction in accuracy in all the cases other than natural lighting condition and fixed distance of acquisition. The same is true with human vision system too. Variations in image sizes also affect the recognition and classification accuracies. Hence, it is inferred that any variation in the size of the image and the distance of acquisition has an impact on the accuracy of recognition of food grain samples.

Machine Vision Optical Scanners for Landslide Monitoring

2017 ◽  
pp. 206-235
Author(s):  
Javier Rivera Castillo ◽  
Moises Rivas-Lopez ◽  
Wendy Flores-Fuentes ◽  
Oleg Sergiyenko ◽  
Julio Cesar Rodríguez-Quiñonez ◽  
...  
Keyword(s):  
Light Source ◽  
Source Monitoring ◽  
Vision System ◽  
Landslide Monitoring ◽  
Light Sources ◽  
Optical Scanners ◽  
Laboratory Environment ◽  
Optical Scanner ◽  
Cylindrical Mirror ◽  
Sloping Surface

An application of landslide monitoring using optical scanner as vision system is presented. The method involves finding the position of non-coherent light sources located at strategic points susceptible to landslides. The position of the light source is monitored by measuring its coordinates using a scanner based on a 45° sloping surface cylindrical mirror. This chapter also provides a background about the concept of landslides and technologies for monitoring. finally, the results of experiments of position light source monitoring in laboratory environment using the proposed method are presented.

Organic Light Emitting Diodes - Innovative Light Sources

2019 ◽  
pp. 101-107
Author(s):  
Sergei A. Stakharny
Keyword(s):  
Light Source ◽  
Organic Light Emitting Diodes ◽  
Organic Leds ◽  
Light Sources ◽  
High Quality ◽  
Light Emitting ◽  
Organic Light ◽  
Lighting Systems ◽  
Physical Principles ◽  
Prospects Of Application

This article is a review of the new light source – organic LEDs having prospects of application in general and special lighting systems. The article describes physical principles of operation of organic LEDs, their advantages and principal differences from conventional non-organic LEDs and other light sources. Also the article devoted to contemporary achievements and prospects of development of this field in the spheres of both general and museum lighting as well as other spheres where properties of organic LEDs as high-quality light sources may be extremely useful.

Use of photodynamic therapy for photodamage skin (review of literature)

2019 ◽  
Vol 1 (7) ◽  
pp. 19-23
Author(s):  
S. I. Surkichin ◽  
N. V. Gryazeva ◽  
L. S. Kholupova ◽  
N. V. Bochkova
Keyword(s):  
Photodynamic Therapy ◽  
Comparative Evaluation ◽  
Clinical Manifestations ◽  
Light Sources ◽  
Review Of Literature ◽  
Photosensitizing Agents ◽  
Selection Of

The article provides an overview of the use of photodynamic therapy for photodamage of the skin. The causes, pathogenesis and clinical manifestations of skin photodamage are considered. The definition, principle of action of photodynamic therapy, including the sources of light used, the classification of photosensitizers and their main characteristics are given. Analyzed studies that show the effectiveness and comparative evaluation in the selection of various light sources and photosensitizing agents for photodynamic therapy in patients with clinical manifestations of photodamage.

Colour Image Enhancement using Perceptual Saturation and Vividness

2019 ◽  
Vol 2019 (1) ◽  
pp. 243-246
Author(s):  
Muhammad Safdar ◽  
Noémie Pozzera ◽  
Jon Yngve Hardeberg
Keyword(s):  
Image Quality ◽  
Image Enhancement ◽  
Test Performance ◽  
Appearance Model ◽  
Colour Space ◽  
Categorical Judgment ◽  
Saturation Scale ◽  
Colour Image ◽  
Colour Appearance ◽  
Future Test

A perceptual study was conducted to enhance colour image quality in terms of naturalness and preference using perceptual scales of saturation and vividness. Saturation scale has been extensively used for this purpose while vividness has been little used. We used perceptual scales of a recently developed colour appearance model based on Jzazbz uniform colour space. A two-fold aim of the study was (i) to test performance of recently developed perceptual scales of saturation and vividness compared with previously used hypothetical models and (ii) to compare performance and chose one of saturation and vividness scales for colour image enhancement in future. Test images were first transformed to Jzazbz colour space and their saturation and vividness were then decreased or increased to obtain 6 different variants of the image. Categorical judgment method was used to judge preference and naturalness of different variants of the test images and results are reported.

scholarly journals Characterizing Color Quality, Damage to Artwork, and Light Intensity of Multi-Primary LEDs for Museums

Heritage ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 188-197
Author(s):  
Dorukalp Durmus
Keyword(s):  
Energy Efficiency ◽  
Appearance Model ◽  
Light Sources ◽  
Great Flexibility ◽  
Oil Paintings ◽  
Damage Reduction ◽  
Output Variability ◽  
Color Quality ◽  
Trade Offs

Light causes damage when it is absorbed by sensitive artwork, such as oil paintings. However, light is needed to initiate vision and display artwork. The dilemma between visibility and damage, coupled with the inverse relationship between color quality and energy efficiency, poses a challenge for curators, conservators, and lighting designers in identifying optimal light sources. Multi-primary LEDs can provide great flexibility in terms of color quality, damage reduction, and energy efficiency for artwork illumination. However, there are no established metrics that quantify the output variability or highlight the trade-offs between different metrics. Here, various metrics related to museum lighting (damage, the color quality of paintings, illuminance, luminous efficacy of radiation) are analyzed using a voxelated 3-D volume. The continuous data in each dimension of the 3-D volume are converted to discrete data by identifying a significant minimum value (unit voxel). Resulting discretized 3-D volumes display the trade-offs between selected measures. It is possible to quantify the volume of the graph by summing unique voxels, which enables comparison of the performance of different light sources. The proposed representation model can be used for individual pigments or paintings with numerous pigments. The proposed method can be the foundation of a damage appearance model (DAM).

scholarly journals Analysis on High-Power Seaport LED Luminaire with Uniform Light Distribution Based on Optimized Lens and Heatsink

2021 ◽  
Vol 11 (9) ◽  
pp. 4035
Author(s):  
Jinsheon Kim ◽  
Jeungmo Kang ◽  
Woojin Jang
Keyword(s):  
Light Source ◽  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Light Distribution ◽  
Light Sources ◽  
Led Light ◽  
High Power Led ◽  
Distribution Requirement ◽  
Lighting Application

In the case of light-emitting diode (LED) seaport luminaires, they should be designed in consideration of glare, average illuminance, and overall uniformity. Although it is possible to implement light distribution through auxiliary devices such as reflectors, it means increasing the weight and size of the luminaire, which reduces the feasibility. Considering the special environment of seaport luminaires, which are installed at a height of 30 m or more, it is necessary to reduce the weight of the device, facilitate replacement, and secure a light source with a long life. In this paper, an optimized lens design was investigated to provide uniform light distribution to meet the requirement in the seaport lighting application. Four types of lens were designed and fabricated to verify the uniform light distribution requirement for the seaport lighting application. Using numerical analysis, we optimized the lens that provides the required minimum overall uniformity for the seaport lighting application. A theoretical analysis for the heatsink structure and shape were conducted to reduce the heat from the high-power LED light sources up to 250 W. As a result of these analyses on the heat dissipation characteristics of the high-power LED light source used in the LED seaport luminaire, the heatsink with hexagonal-shape fins shows the best heat dissipation effect. Finally, a prototype LED seaport luminaire with an optimized lens and heat sink was fabricated and tested in a real seaport environment. The light distribution characteristics of this prototype LED seaport luminaire were compared with a commercial high-pressure sodium luminaire and metal halide luminaire.

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