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.

scholarly journals Active Recurrence of Lighting Condition for Fine-Grained Change Detection

2018 ◽  
Author(s):  
Qian Zhang ◽  
Wei Feng ◽  
Liang Wan ◽  
Fei-Peng Tian ◽  
Ping Tan
Keyword(s):  
Change Detection ◽  
Light Source ◽  
Real World ◽  
Reference Image ◽  
Light Sources ◽  
Lighting Condition ◽  
Fine Grained ◽  
Lighting Conditions ◽  
Point Light ◽  
Change Monitoring

This paper addresses active lighting recurrence (ALR), a new problem that actively relocalizes a light source to physically reproduce the lighting condition for a same scene from single reference image. ALR is of great importance for fine-grained visual monitoring and change detection, because some phenomena or minute changes can only be clearly observed under particular lighting conditions. Hence, effective ALR should be able to online navigate a light source toward the target pose, which is challenging due to the complexity and diversity of real-world lighting \& imaging processes. We propose to use the simple parallel lighting as an analogy model and based on Lambertian law to compose an instant navigation ball for this purpose. We theoretically prove the feasibility of this ALR strategy for realistic near point light sources and its invariance to the ambiguity of normal \& lighting decomposition. Extensive quantitative experiments and challenging real-world tasks on fine-grained change monitoring of cultural heritages verify the effectiveness of our approach. We also validate its generality to non-Lambertian scenes. 

An Evaluation of Some VDT Lighting Variables

1987 ◽  
Vol 31 (10) ◽  
pp. 1109-1112 ◽  
Author(s):  
Stephan Konz ◽  
Corwin Bennett
Keyword(s):  
Light Source ◽  
Ambient Light ◽  
Lighting Conditions

It has been difficult to differentiate statistically among lighting conditions. A questionnaire, using 12 positive adjectives, was developed which was sensitive enough to show differences among lighting variables. Twenty subjects each spent 20 minutes in each of 12 conditions. The 12 conditions were all combinations of screen glare (high and low), ambient light source (kiosk and kiosk + ceiling), and document luminance (25, 160 and 320 cd/m2). The criterion was put on a scale of 0–100%. Kiosk + ceiling lighting (score = 69%) was preferred to kiosk lighting (59%). Medium document brightness (73%) was preferred to high (63%) and low (56%). Low glare (67%) was preferred to high glare (61%).

scholarly journals ВИКОРИСТАННЯ ОПТОВОЛОКНА ЯК СКЛАДОВОЇ ЗАГАЛЬНОГО ЗОВНІШНЬОГО ОСВІТЛЕННЯДЛЯ СТВОРЕННЯ МАКСИМАЛЬНОГО РІВНЯ ЕНЕРГОЕФЕКТИВНОСТІ

2021 ◽  
pp. 40-47
Author(s):  
ALINA YATSENKO ◽  
IRYNA OLEINIKOVA
Keyword(s):  
Optical Fiber ◽  
Light Source ◽  
Energy Efficient ◽  
The State ◽  
Light Sources ◽  
Lighting System ◽  
Additional Energy ◽  
Outdoor Sports ◽  
Illumination System ◽  
Light Load

Purpose. To develop a new lighting system for children's sports complexes. The introduction of the developed technology will improve the state of illumination of outdoor sports grounds without creating light pollution and increasing additional energy-efficient costs.Methodology. The combined technique of the technology of using two types of light sources, namely: low-power LED floodlights and optical fiber with a single light source, allows you to create an energy-efficient field illumination system. The proposed solution can be used for full illumination of street children's complexes. The selection of the parameters of the lighting system was carried out on the example of a real sports and children's complex.Findings. The performed measurements of the real parameters of the existing sports ground and taking into account its geometry allowed us to calculate the light parameters of light sources, select the appropriate materials and create a complete lighting model. A new lighting technology for sports and children's complexes has been developed, the level of lighting of sports facilities has been improved without creating light pollution.Originality. For the first time, a combined technology of illumination of sports and children's playgrounds was proposed using optical fiber and LED floodlights. The introduction of the developed technology will improve the state of illumination of such structures without creating an unnecessary light load on residents who are near the site. Moreover, such lighting will not lead to an increase in additional energy costs.Practical value. Today, most outdoor sports and entertainment venues are devoid of any lighting. The proposed complex solution can be used in any existing field lighting system. It is the most efficient and electrically safe because the optical fiber does not conduct electricity, but light. The light source itself can be located remotely and protected from vandals.

scholarly journals Image Based Shadowing in Real-Time Augmented Reality

2006 ◽  
Vol 5 (3) ◽  
pp. 1-7 ◽  
Author(s):  
Peter Supan ◽  
Ines Stuppacher ◽  
Michael Haller
Keyword(s):  
Augmented Reality ◽  
Real Time ◽  
Light Source ◽  
Light Sources ◽  
Virtual Objects ◽  
Lighting Conditions ◽  
Shadow Casting ◽  
Real Objects

This work presents an approach to render appropriate shadows with Image Based Lighting in Augmented Reality applications. To approximate the result of environment lighting and shadowing, the system uses a dome of shadow casting light sources. The color of each shadow is determined by the area of the environment behind the casting light source. As a result it is possible that changes in the lighting conditions immidiately affect the shadow casting of virtual objects on real objects

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.

Research on Improved Gamma Transform Face Image Preprocessing Fusion Algorithm under Complex Lighting Conditions

2020 ◽  
Vol 13 ◽  
Author(s):  
Xiaolin Tang ◽  
Xiaogang Wang ◽  
Jin Hou ◽  
Huafeng Wu ◽  
Ping He
Keyword(s):  
Edge Detection ◽  
Face Image ◽  
Light Sources ◽  
Fusion Algorithm ◽  
Edge Information ◽  
Image Preprocessing ◽  
Lighting Conditions ◽  
Weighted Fusion ◽  
The Face ◽  
Sobel Edge Detection

Introduction: Under complex illumination conditions such as poor light sources and light changes rapidly, there are two disadvantages of current gamma transform in preprocessing face image: one is that the parameters of transformation need to be set based on experience; the other is the details of the transformed image are not obvious enough. Objective: Improve the current gamma transform. Methods: This paper proposes a weighted fusion algorithm of adaptive gamma transform and edge feature extraction. First, this paper proposes an adaptive gamma transform algorithm for face image preprocessing, that is, the parameter of transformation generated by calculation according to the specific gray value of the input face image. Secondly, this paper uses Sobel edge detection operator to extract the edge information of the transformed image to get the edge detection image. Finally, this paper uses the adaptively transformed image and the edge detection image to obtain the final processing result through a weighted fusion algorithm. Results: The contrast of the face image after preprocessing is appropriate, and the details of the image are obvious. Conclusion: The method proposed in this paper can enhance the face image while retaining more face details, without human-computer interaction, and has lower computational complexity degree.

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.

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.

Hybrid-Light-Source Stereolithography for Fabricating Macro-Objects With Micro-Textures

2021 ◽  
Author(s):  
Wenxuan Jia ◽  
Yuen-Shan Leung ◽  
Huachao Mao ◽  
Han Xu ◽  
Chi Zhou ◽  
...  
Keyword(s):  
Light Source ◽  
Dimensional Accuracy ◽  
Beam Width ◽  
Surface Structures ◽  
Light Sources ◽  
Scanning Method ◽  
Hardware System ◽  
Building Area ◽  
Micro Features ◽  
Display Resolution

Abstract Microscale surface structures are commonly found on macroscale bodies of natural creatures for their unique functions. However, it is difficult to fabricate such multi-scale geometry with conventional stereolithography processes that rely on either laser or digital micromirror device (DMD). More specifically, the DMD-based mask projection method displays the image of a cross-section of the part on the resin to fabricate the entire layer efficiently; however, its display resolution is limited by the building area. In comparison, the laser-based vector scanning method builds smooth features using a focused laser beam with desired beam-width resolution; however, it has less throughput for its sequential nature. In this paper, we studied the hybrid-light-source stereolithography process that integrates both optical light sources to facilitate the fabrication of macro-objects with microscale surface structures (called micro-textures in the paper). The hardware system uses a novel calibration approach that ensures pixel-level dimensional accuracy across the two light sources. The software system enables designing the distribution and density of specific microscale textures on a macro-object by generating projection images and laser toolpaths for the two integrated light sources. Several test cases were fabricated to demonstrate the capability of the developed process. A large fabrication area (76.8 mm × 80.0 mm) with 50 μm micro-features can be achieved with a high throughput.

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