A Deterministic Method for Aligning Multiple Optical Waveguides to a Paraboloidal Collector

Solar Energy ◽  
2003 ◽  
Author(s):  
L. C. Maxey ◽  
B. J. Hilson
Keyword(s):  
Optical Waveguides ◽  
Imaging System ◽  
Focal Point ◽  
Spot Size ◽  
Deterministic Method ◽  
Small Collection ◽  
Solar Lighting ◽  
Final Adjustment ◽  
Lighting Systems

For solar lighting systems employing fiber optic waveguides1,2, to conduct the collected light, paraboloidal mirrors are the preferred reflector choice. To achieve optimum performance in systems with relatively small collection apertures, both the quality of the mirror and the quality of optical system alignment must be well controlled. In systems employing multiple waveguides with a single paraboloid, the focus of the paraboloid must be segmented into several separate focal points directed into individual fibers. Each waveguide entrance aperture must be accurately co-located with its designated focal point so that the image that is formed on the fiber will have the fewest possible aberrations and thus, the smallest possible focused spot size. Two methods for aligning individual optical waveguides in a multi-aperture paraboloidal collection system are described. The first method employs a commercially available collimation tester to incrementally improve the alignment. The second, a deterministic method, employs a cube corner retro-reflector and an easily constructed imaging system to reliably align the fibers to their respective segments of the parent paraboloid. The image of the focused spot formed by the light that is returned from the retro-reflector reveals alignment information that is easily interpreted to enable pitch, yaw and focus errors to be systematically removed. This ensures that the alignment of the system is optimized to reduce aberrations prior to final adjustment of the system “on-sun”.

scholarly journals Design of Solar Transmission System using Fiber Optic for Indoor Lighting

KnE Energy ◽  
2015 ◽  
Vol 2 (2) ◽  
pp. 59 ◽  
Author(s):  
Elita Fidiya Nugrahani ◽  
Reza Arraffi Birahmatika ◽  
Epri Wahyu Pratiwi ◽  
Sekartedjo K
Keyword(s):  
Optical Fiber ◽  
Focal Point ◽  
Light Output ◽  
Lighting System ◽  
Output Intensity ◽  
Final Project ◽  
Collector System ◽  
Solar Lighting ◽  
Lighting Systems ◽  
Parabolic Collector

<p>Transmission of fiber solar lighting system is a lighting system using sunlight as a source. The system consists of two main components, there are: solar collectors and optical fiber. Solar collector is used to collect and focus sunlight into the focal point. Sunlight that received by collector is transmitted by optical fiber into the room, primarily through efficiency of the collector system. In this final project, we designed the transmission systems via optical fiber for lighting on the Photonics Laboratory ITS. Transmission of solar lighting systems used parabolic collector as a major collector and end glow plastic optical fiber as the transmission with length of 50m. There are four types of collector systems were designed, i.e. parabolic, parabolic with flat mirrors, parabolic with pyramid and parabolic with a cone. Characterization system consists of measuring reflectance values, the output intensity of the optical fiber, and the intensity light distribution in the room. The results of measurements of the reflectance (R) collector surface with paint gray and silver are 0.225 and 0.475, respectively. In the measurement light output intensity of the optical fiber with variation types of collector systems, it is obtained that the highest value from the combination of parabolic collector with a cone. Distribution of light output from the optical fiber in the room was also calculated and measured. </p><p><strong>Keywords</strong>: collector; optical fiber; solar lighting</p>

scholarly journals Modeling and image quality enhancement for dynamic compressive imaging system

2021 ◽  
Vol 15 ◽  
pp. 174830262110080
Author(s):  
Changjun Zha* ◽  
Qian Zhang* ◽  
Huimin Duan
Keyword(s):  
Image Quality ◽  
Imaging System ◽  
Quality Enhancement ◽  
Target Image ◽  
Compressive Imaging ◽  
Image Quality Enhancement ◽  
System A ◽  
Single Column ◽  
The Impact

Traditional single-pixel imaging systems are aimed mainly at relatively static or slowly changing targets. When there is relative motion between the imaging system and the target, sizable deviations between the measurement values and the real values can occur and result in poor image quality of the reconstructed target. To solve this problem, a novel dynamic compressive imaging system is proposed. In this system, a single-column digital micro-mirror device is used to modulate the target image, and the compressive measurement values are obtained for each column of the image. Based on analysis of the measurement values, a new recovery model of dynamic compressive imaging is given. Differing from traditional reconstruction results, the measurement values of any column of vectors in the target image can be used to reconstruct the vectors of two adjacent columns at the same time. Contingent upon characteristics of the results, a method of image quality enhancement based on an overlapping average algorithm is proposed. Simulation experiments and analysis show that the proposed dynamic compressive imaging can effectively reconstruct the target image; and that when the moving speed of the system changes within a certain range, the system reconstructs a better original image. The system overcomes the impact of dynamically changing speeds, and affords significantly better performance than traditional compressive imaging.

scholarly journals Problematizing Olympic Nationality

AJIL Unbound ◽  
2020 ◽  
Vol 114 ◽  
pp. 374-379
Author(s):  
Peter J. Spiro
Keyword(s):  
Twentieth Century ◽  
National Identity ◽  
Focal Point ◽  
Professional Sports ◽  
Sports Teams ◽  
Olympic Athletes ◽  
Nation States ◽  
International Solidarity

One can hope that the convening of the Tokyo Olympics will be a cause for global celebration. Tokyo could prove a focal point for international solidarity, a moment of relief and release after all of humanity faced down an insidious, invisible, and largely indiscriminate attacker. Unified as we otherwise may be, athletes will still come to the Games as representatives of nation-states. That may be an unavoidable organizing principle. Less justifiable will be the requirement that athletes be nationals of the states they play for. Under the Olympic Charter and the rules of particular sporting federations, athletes are subject to a non-state nationality regime that restricts the capacity of individuals to compete for countries for whose delegations they would otherwise qualify. This regime looks to maintain the putative integrity of Olympic competition by maintaining the unity of sporting and sociological national identity. But that legacy of the twentieth century no longer works in the twenty first. Nationality and associated criteria for participant eligibility undermine the autonomy of athletes and the quality of participation. The rules can no longer guarantee any affective tie between athlete and nation, instead arbitrarily enabling some, but not all, to compete on the basis of citizenship decoupled from identity. We don't require that athletes playing for our professional sports teams hale from the cities they represent. There's no reason why we need to require more of our Olympic athletes.

scholarly journals Increased Plant Quality, Greenhouse Productivity and Energy Efficiency with Broad-Spectrum LED Systems: A Case Study for Thyme (Thymus vulgaris L.)

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 960
Author(s):  
Jenny Manuela Tabbert ◽  
Hartwig Schulz ◽  
Andrea Krähmer
Keyword(s):  
Broad Spectrum ◽  
Energy Savings ◽  
Light Emitting Diode ◽  
Thymus Vulgaris ◽  
Light Spectrum ◽  
Light Emitting ◽  
Biomass Yields ◽  
Lighting Systems

A light-emitting diode (LED) system covering plant-receptive wavebands from ultraviolet to far-red radiation (360 to 760 nm, “white” light spectrum) was investigated for greenhouse productions of Thymus vulgaris L. Biomass yields and amounts of terpenoids were examined, and the lights’ productivity and electrical efficiency were determined. All results were compared to two conventionally used light fixture types (high-pressure sodium lamps (HPS) and fluorescent lights (FL)) under naturally low irradiation conditions during fall and winter in Berlin, Germany. Under LED, development of Thymus vulgaris L. was highly accelerated resulting in distinct fresh yield increases per square meter by 43% and 82.4% compared to HPS and FL, respectively. Dry yields per square meter also increased by 43.1% and 88.6% under LED compared to the HPS and FL lighting systems. While composition of terpenoids remained unaffected, their quantity per gram of leaf dry matter significantly increased under LED and HPS as compared to FL. Further, the power consumption calculations revealed energy savings of 31.3% and 20.1% for LED and FL, respectively, compared to HPS. In conclusion, the implementation of a broad-spectrum LED system has tremendous potential for increasing quantity and quality of Thymus vulgaris L. during naturally insufficient light conditions while significantly reducing energy consumption.

Assessing the impact of the transition to Light Emitting Diodes based solar lighting systems in India

2013 ◽  
Vol 17 (4) ◽  
pp. 363-370 ◽  
Author(s):  
Santosh M. Harish ◽  
Shuba V. Raghavan ◽  
Milind Kandlikar ◽  
Gireesh Shrimali
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting ◽  
Solar Lighting ◽  
Lighting Systems ◽  
The Impact

Development of a three-dimensional color rendition space for tunable solid-state light sources

2021 ◽  
Vol 2021 (29) ◽  
pp. 136-140
Author(s):  
Dorukalp Durmus
Keyword(s):  
Solid State ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Color Discrimination ◽  
Continuous Measure ◽  
Light Sources ◽  
Vast Number ◽  
Lighting Systems ◽  
Single Number

The quality of building electric lighting systems can be assessed using color rendition metrics. However, color rendition metrics are limited in quantifying tunable solid-state light sources, since tunable lighting systems can generate a vast number of different white light spectra, providing flexibility in terms of color quality and energy efficiency. Previous research suggests that color rendition is multi-dimensional in nature, and it cannot be simplified to a single number. Color shifts under a test light source in comparison to a reference illuminant, changes in color gamut, and color discrimination are important dimensions of the quality of electric light sources, which are not captured by a single-numbered metric. To address the challenges in color rendition characterization of modern solid-state light sources, the development of a multi-dimensional color rendition space is proposed. The proposed continuous measure can quantify the change in color rendition ability of tunable solid-state light devices with caveats. Future work, discretization of the continuous color rendition space, will be carried out to address the shortcomings of a continuous three-dimensional space.

A Thermal Model of a Fiber Optic Bundle for a Hybrid Solar Lighting System

2005 ◽  
Author(s):  
Michael J. Cheadle ◽  
Gregory F. Nellis ◽  
Sanford A. Klein ◽  
William A. Beckman
Keyword(s):  
Energy Consumption ◽  
Thermal Model ◽  
Fiber Optic ◽  
Management Strategies ◽  
Design Tool ◽  
Lighting Energy ◽  
Solar Lighting ◽  
Reduce Energy Consumption ◽  
Lighting Systems ◽  
Cooling Loads

Hybrid solar lighting (HSL) systems distribute natural sunlight to luminaires located in office or retail buildings in order to reduce energy consumption associated with conventional lighting systems. HSL systems reduce energy consumption directly by reducing the lighting energy and indirectly by reducing the associated cooling loads. A key component of the HSL system is the fiber optic bundle (FOB) that transmits the light from the collector to the luminaire. The observed thermal failure of the FOB when exposed to concentrated sunlight has motivated the development of a thermal model of this component. This paper describes the development of a predictive thermal model of the heat transfer in an FOB for an HSL system. The model is verified experimentally against temperature measurements obtained in the lab under controlled conditions and provides a powerful design tool that can be used to evaluate alternative thermal management strategies.

scholarly journals HYBRID ONLINE MOBILE LASER SCANNER CALIBRATION THROUGH IMAGE ALIGNMENT BY MUTUAL INFORMATION

2016 ◽  
Vol III-1 ◽  
pp. 25-31 ◽  
Author(s):  
Mourad Miled ◽  
Bahman Soheilian ◽  
Emmanuel Habets ◽  
Bruno Vallet
Keyword(s):  
Mutual Information ◽  
Imaging System ◽  
Laser Scanner ◽  
Point Clouds ◽  
Calibration Method ◽  
Online Calibration ◽  
Calibration Methods ◽  
Laser Calibration ◽  
Scanner Calibration

This paper proposes an hybrid online calibration method for a laser scanner mounted on a mobile platform also equipped with an imaging system. The method relies on finding the calibration parameters that best align the acquired points cloud to the images. The quality of this intermodal alignment is measured by Mutual information between image luminance and points reflectance. The main advantage and motivation is ensuring pixel accurate alignment of images and point clouds acquired simultaneously, but it is also much more flexible than traditional laser calibration methods.

Restoration of Motion Blurred Image Based on PSO Combine Wiener Filter in Ship Imaging System

2014 ◽  
Vol 1006-1007 ◽  
pp. 739-742
Author(s):  
Hui Xuan Fu ◽  
Yu Chao Wang ◽  
Xun Su
Keyword(s):  
Imaging System ◽  
Search Algorithm ◽  
Wiener Filter ◽  
Optimal Solution ◽  
Parameter Selection ◽  
Improve Image Quality ◽  
Blurred Image ◽  
Blurred Images ◽  
Ringing Effect

Ship internal equipment vibration will cause the imaging system platform vibration, resulting in blurred images. Wiener Filter is often used to restore the motion blurred image. The principle of the method expects to minimize the mean square error between the restore image and original image. However, this method has some constrains, if parameter selection improper, it generates ringing effect easily. Usually, most users select parameter by rule of thumb, so they frequently fail to generate the optimal solution. In order to get high quality restore image, eliminate the ringing effect, a new approach based on particle swarm optimization (PSO) Wiener Filter was proposed, which automatically adjusts the parameter for Wiener Filter, this method seek the optimal solution by transferring information between individuals and information sharing, which is a highly efficient parallel search algorithm, insuring the accuracy of parameter selection, effectively reducing the ringing effect after image restoration, improve image quality of restoration.

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