Dissertations / Theses on the topic 'RGBW LEDs'
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Coufal, Miroslav. "Modulární RGB LED displej." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220135.
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The aim of this master’s thesis was the design RGB LED display with Ethernet interface. I created a display module, controlled by a microcontroller ATmega 2560-16AU. These modules can be connected via a serial RS485 standard. Ethernet connection is made via plug-in interface that uses the programmable module Rabbit RCM 3200. I documented a proposal. I tested designed device.
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Zemánek, Petr. "Modulární RGB LED displej s rozhraním Ethernet." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220700.
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This thesis deals with an electronic circuit and a PCB of a modular RGB LED display with the Ehernet interface. Firstly, author describes a RGB colour model, features of RGB LED displays, ways of control them. The next chapter contains a short description of the Ethernet interface, UDP and TCP protocols and a lwIP TCP/IP stack. The last theoretical chapter is an introduction to ARM Cortex-M3 and Cortex-M4 based microcontrollers. The next chaper is deals with a hardware design of the modular RGB LED display. The device is designed to be modular. Individual devices can be combosed together and create a larger display. Data from the Ethernet interface will be displayed on the RGB LED matrix, resolution of the matrix is 32 × 32 (1024 diodes). A refresh frequency is 100 Hz, a color depth is High color (16 bits) and a scanning 1/16 (two rows is driven at the same time). The next chapter describes the firmware for the RGB LED display, all its logical parts including a web page. Author also created the PC application, which sends pictures using UDP protocol to individual modules.
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Левковський, О. В. "Світлодіодна стрічка. RGB–стрічка." Thesis, Сумський державний університет, 2015. http://essuir.sumdu.edu.ua/handle/123456789/43713.
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В останній час світлодіодні стрічки набирають все більшу популярність в житті та побуті людей. Світлодіодна стрічка - джерело світла, зібраного на основі світлодіодів. Являє собою гнучку друковану (монтажну) плату, на якій рівновіддалено один від одного розташовані світлодіоди.
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Šunka, Pavel. "Aplikace FPGA v řízení maticových displejů LED." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-376970.
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The thesis gives an overview of the issue of control of full-color RGB LED panels with a large number of rows and columns. It deals with communication protocols for image transfer and information exchange. It focuses on implementing the FPGA into the RGB LED control structure. In the first half, the thesis focuses on deepening the theoretical knowledge about LED technologies, their control and color display. It further solves communication with superior elements. The last part of the theory is dedicated to FPGA circuits. The second part of the thesis describes the practical design of the FPGA circuit from UART and SPI communication through data storage from the communication to the panel control itself.
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Biba, Panagiota. "New waviness measurement system using RGB LED lights." Thesis, Högskolan i Halmstad, Akademin för informationsteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-28314.
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Due to the rapid technological developments in the car industry and the high quality demands of customers, manufacturers and researchers focus on the reduction of surface roughness making use of various surface topography measurement systems. This master thesis focuses on development of a waviness measurement system (WMS) at Volvo Cars where light from different heights and angles illuminates the surface of an extended object in order to acquire images with different intensities due to shadowing effect and reflection. With this, surface irregularities and imperfections can be detected both in polished and unpolished surfaces for improving the car panels in the manufacturing process. The initial WMS idea was to illuminate the surface at different heights from the four corners of a dark room using 20 flash lights and a camera positioned exactly on the top of the surface in the middle of the room. The first light goes on and the image is acquired. This procedure continues for all flash lights in 19s.The acquired images were evaluated by Matlab application. With the new WMS system flash lights are replaced by 32 RGB COB LED lights using the DMX512 protocol to communicate with them. The system runs in 9s which is half the time of the old WMS system. New LabView and Matlab codes were adjusted to the new parameters and devices. In the end, measurements were taken with different surfaces, exposure times and color lights. Details of the new devices and software are analyzed in this thesis.
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Baldárrago, Catcoparco Jhair Andree. "Diseño de efectos y variación de colores mediante degradé en leds de potencia RGB aplicados a paneles publicitarios." Bachelor's thesis, Pontificia Universidad Católica del Perú, 2010. http://tesis.pucp.edu.pe/repositorio/handle/123456789/527.
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En el presente trabajo se realizó el diseño de efectos con colores mediante
degradés en una matriz de LEDs de potencia RGB orientado a paneles publicitarios,
con el objetivo de implementar este sistema de iluminación como una opción frente
a los métodos tradicionales, pues estos últimos ofrecen muchas desventajas, tanto
en la parte visual como en la parte económica. Además de incluir en el diseño, una
interfaz para ser operada por un usuario, de manera fácil e intuitiva, la cual
actualmente no es brindada por los equipos comerciales que ofrecen este tipo de
iluminación, pues estos ya vienen predeterminados desde su fabricación.
El diseño realizado consta de 2 partes. La primera parte es el desarrollo del
software, es decir, el programa cuyo fin es lograr el degradés de los colores, así
como los efectos realizados con estos; mientras que la segunda parte es el
hardware, lo que incluye tanto los controladores de potencia para los LEDs, como
los LEDs mismos y la tarjeta de control de todo el sistema. Ambas partes, así como
la investigación previa, están documentadas en 4 capítulos.
En el primer capítulo, se definen los métodos de publicidad visual, dentro de los
cuales se encuentra la publicidad exterior (paneles), así como la visión humana y
sus características en función a los colores.
Luego, en el segundo capítulo, se muestra el estado actual de la iluminación con
LEDs de potencia RGB, su funcionamiento y aplicaciones actuales en la industria.
En el tercer capítulo, se desarrolla el diseño planteado para cubrir los objetivos,
tanto en la parte de hardware (controladores, LEDs de potencia, etc.) como en
software (desarrollo de programa).
Finalmente, en el cuarto capítulo, se presentan las simulaciones y fotografías, las
cuales prueban en correcto funcionamiento de los subsistemas que conforman la
iluminación con LEDs, así como el sistema integral conjunto.
Además, en la última parte se presentan las conclusiones y recomendaciones en el
desarrollo del prototipo presentado, para que puedan ser tomadas en cuenta para
futuras mejoras de este.Tesis
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Medrano, Arias Eduardo Alfredo. "Rediseño e implementación de un sistema de iluminación para espacios publicitarios usando Led RGB." Bachelor's thesis, Pontificia Universidad Católica del Perú, 2010. http://tesis.pucp.edu.pe/repositorio/handle/123456789/509.
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Los sistemas de iluminación son desarrollos que permiten al hombre visualizar de una mejor
forma a los objetos desde un punto de vista artístico y funcional. Estos sistemas tienen un
amplio campo de aplicación en nuestra vida diaria. Están referidos al proceso en el cual la
iluminación forma parte del diseño del objeto usando dispositivos capaces de satisfacer el tipo,
calidad y color de luz que se requiere.
Dado que en el Perú los sistemas de iluminación cumplen una gran importancia como elemento
que forma parte del diseño de espacios públicos y comerciales, es necesario enfrentar el
problema de la iluminación conociendo las características de ella. Por esto se plantea la
utilización de una nueva tecnología como el LED (Light-Emitting Diode) de potencia en el
desarrollo de sistemas de iluminación aprovechando las características que este dispositivo
trae.
La presente tesis consiste en el rediseño e implementación de un sistema de iluminación
aplicado a un display1 publicitario de una superficie de 25x25cm2. Uno de los objetivos es
mejorar la iluminación mediante la aplicación de la nueva tecnología, el LED RGB (Red Green
Blue) que permite obtener un color determinado, rojo, verde y azul; además de variar su
intensidad de brillo. Con el uso de lentes convergentes es posible mezclar los colores primarios
para obtener los colores secundarios; amarillos, cian y magenta; y el color blanco.
El siguiente documento se encuentra dividido en cuatro capítulos principales; el primero de
ellos explica la importancia de la iluminación publicitaria en espacios publicitarios.
El segundo capítulo brinda información sobre la evolución de los sistemas de iluminación
convencionales hasta llegar a la tecnología LED.
El tercer capítulo muestra las consideraciones para el rediseño e implementación del sistema,
los componentes elegidos, así como los cálculos y criterios de selección.
El último capítulo menciona los resultados obtenidos, análisis de costo y conclusiones finales.
Al final del documento se muestra las recomendaciones, sobre el rendimiento del sistema de
iluminación y como mejorarlo, las referencias utilizadas y en la sección de anexos hojas de
datos de los componentes utilizados.Tesis
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Lara, Alvarado Carlo Manuel. "Diseño de un sistema de iluminación para espacios publicitarios pequeños usando Leds de potencia RGB / Carlo Manuel Lara Alvarado." Bachelor's thesis, Pontificia Universidad Católica del Perú, 2009. http://tesis.pucp.edu.pe/repositorio/handle/123456789/258.
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Debido al acelerado desarrollo de los semiconductores, en los últimos 15 años, se
ha logrado dejar de usar a los LEDs como simplemente fuentes de señalización en
diversas aplicaciones minúsculas, por ejemplo en los muy conocidos displays de 7
segmentos o como puntos brillantes en los teclados y circuitos electrónicos, para
pasar con fuerza al ámbito de la iluminación. Es así, como grandes empresas
internacionales han fijado su interés en el desarrollo y afianzamiento en el mercado
de los llamados LEDs de potencia o alto brillo, dado que, como su nombre lo indica,
han llegado a multiplicar su capacidad de generar luz y mejorar su eficiencia
luminosa hasta el punto de competir y superar otros tipos tradicionales de fuentes
de iluminación.
Es por estas razones, que el objetivo de este trabajo de tesis es diseñar un sistema
de iluminación usando LEDs de potencia RGB para espacios publicitarios de
tamaño pequeño, ya que el ámbito de la publicidad es un mercado donde se
permite aplicar todo el potencial de una nueva tecnología de iluminación multicolor.Tesis
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Stuchi, José Augusto. "Registro de imagens por correlação de fase para geração de imagens coloridas em retinógrafos digitais utilizando câmera CCD monocromática." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18152/tde-18072013-110903/.
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A análise da retina permite o diagnostico de muitas patologias relacionadas ao olho humano. A qualidade da imagem e um fator importante já que o médico normalmente examina os pequenos vasos da retina e a sua coloração. O equipamento normalmente utilizado para a visualização da retina e o retinógrafo digital, que utiliza sensor colorido com filtro de Bayer e luz (flash) branca. No entanto, esse filtro causa perda na resolução espacial, uma vez que e necessário um processo de interpolação matemática para a formação da imagem. Com o objetivo de melhorar a qualidade da imagem da retina, um retinógrafo com câmera CCD monocromática de alta resolução foi desenvolvido. Nele, as imagens coloridas são geradas pela combinação dos canais monocromáticos R (vermelho), G (verde) e B (azul), adquiridos com o chaveamento da iluminação do olho com LED vermelho, verde e azul, respectivamente. Entretanto, o pequeno período entre os flashes pode causar desalinhamento entre os canais devido a pequenos movimentos do olho. Assim, este trabalho apresenta uma técnica de registro de imagens, baseado em correlação de fase no domínio da frequência, para realizar precisamente o alinhamento dos canais RGB no processo de geração de imagens coloridas da retina. A validação do método foi realizada com um olho mecânico (phantom) para a geração de 50 imagens desalinhadas que foram corrigidas pelo método proposto e comparadas com as imagens alinhadas obtidas como referência (ground-truth). Os resultados mostraram que retinógrafo com câmera monocromática e o método de registro proposto nesse trabalho podem produzir imagens coloridas da retina com alta resolução espacial, sem a perda de qualidade intrínseca às câmeras CCD coloridas que utilizam o filtro de Bayer.The analysis of retina allows the diagnostics of several pathologies related to the human eye. Image quality is an important factor since the physician often examines the small vessels of the retina and its color. The device usually used to observe the retina is the fundus camera, which uses color sensor with Bayer filter and white light. However, this filter causes loss of spatial resolution, since it is necessary a mathematical interpolation process to create the final image. Aiming at improving the retina image quality, a fundus camera with monochromatic CCD camera was developed. In this device, color images are generated by combining the monochromatic channels R (red), G (green) and B (blue), which were acquired by switching the eye illumination with red, green and blue light, respectively. However, the short period between the flashes may cause misalignment among the channels because of the small movements of the eye. Thus, this work presents an image registration technique based on phase correlation in the frequency domain, for accurately aligning the RGB channels on the process of generating retina color images. Validation of the method was performed by using a mechanical eye (phantom) for generating 50 misaligned images, which were aligned by the proposed method and compared to the aligned images obtained as references (ground-truth). Results showed that the fundus camera with monochromatic camera and the method proposed in this work can produce high spatial resolution images without the loss of quality intrinsic to color CCD cameras that uses Bayer filter.
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Ashiabor, Awo Dede O. "A design for an RGB LED driver with independent PWM control and fast settling time." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41251.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (leaves 76-77).
A small sized and efficient method to power RGB LEDs for use as backlights in flat panel displays is explored in this thesis. The proposed method is to drive a parallel switched connection of LEDs with a single Average Mode Controlled buck regulator.Specifications for the switching regulator and control circuitry are described. The application circuit demonstrates current settling times between 7[mu]s and 30[mu]s at a switching frequency of 290kHz. Current settling is improved at higher switching frequencies, with settling times approaching a 2[mu]s to 4[mu]s range at 1MHz switching.
by Awo Dede O. Ashiabor.
M.Eng.
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Palacios, Ana. "Processus de transport et nucléosynthèse dans les étoiles évoluées." Toulouse 3, 2002. http://www.theses.fr/2002TOU30174.
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Dans le cadre du problème de l'étude des "anomalies d'abondances" observées à la surface des étoiles géantes rouges, ce travail de thèse a consisté à étudier les effets de la rotation sur le transport du moment cinétique et des espèces chimiques au cours de l'évolution des étoiles de faible masse. Après avoir déterminé les caractéristiques que doit avoir le mélange non-standard pour reproduire les observations, j'ai inclus dans le code d'évolution stellaire STAREVOL, le traitement du transport rotationnel dans les intérieurs radiatifs stellaires sous l'action combinée de la circulation méridienne et de la turbulence. Si ces processus permettent de reproduire les observations du côté chaud de la brèche du lithium, ils se sont avérés être inefficaces à modifier les abondances de surface des géantes rouges. Nous proposons cependant un scénario physique auto-cohérent, utilisant la rotation comme détonateur d'une série d'évènements permettant de reproduire une grande partie des observationsIn this thesis, we have studied the effects of rotation on the transport of angular momentum and chemicals all along the evolution of low-mass stars. This work was done within the framework of the study of abundance anomalies observed at the surface of low mass red giant stars. I have first determined the properties required for the non-standard mixing to account for the observations. I have then implemented the treatment of rotation-induced transport through meridional circulation and turbulence in stellar radiative interiors in the STAREVOL stellar evolution code. While these processes can account for observations on the hot side of the lithium dip, they appeared to fail in changing the surface abundances of low mass red gieant stars. We nevertheless propose a physical and self-consistent scenario, using rotation as the trigger to a series of events leading to the observed patterns
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Palmqvist, Linnea, and Hillevi Nilsson. "Musikvisualisering med LED-kub." Thesis, Uppsala universitet, Institutionen för materialvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-412444.
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En 4x4x4 kub konstrueras av RGB LED's med integrerad drivrutin och via en Arduino styrs den av musiken som spelas. Arduinon får musiken som input och med hjälp av fouriertransform delas signalen upp i 128 logaritmiskt uppdelade bins. Efter många olika teorier om hur bas, volym och känsla skulle kunna bestämmas i Arduinon bestämdes slutligen att de skulle bero av olika frekvensintervall; basen i 50-250 Hz, volymen i 500-2000 Hz och känslan i 2000-4000 Hz. Basen förflyttar mönstret framåt, volymen bestämmer ljusintensiteten (mellan 50% - 100% av max) och känslan avgör vilket av 6 mönster som aktiveras.
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Guerreiro, Thiago Brito. "Desenvolvimento e aplicação de um fotômetro/fluorímetro microcontrolado à base de LED RGB para a determinação de espécies de interesse analítico." Universidade Federal de São Carlos, 2015. https://repositorio.ufscar.br/handle/ufscar/7716.
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In this work, a photometer/fluorometer micro-controlled (P2FM) multifunctional, portable, communicated by USB 2.0, robust, easy handling and with low consumption of energy was developed. The P2FM was built using a micro-controlled (PIC-18F2455) as central unit of process (CPU), two tricolors LEDs (470, 528, 621 nm) as source of radiation, a multichannel sensor (TCS3200) and the management program wrote in Visual Studio. One of the two LED was used as radiation source for photometric mode. The TCS-3200 is a multichannel sensor with four photosensitive tracks: 480, 540, 750 e 830 nm, being that selection of track is performed by program controlled. The management program operates sending functions for microcontroller, record of dates and storage of signal (*.txt) through of USB port 2.0 (5.0 VCC, 300 mA). The P2FM is compact, with 3.5 cm × 7.0 cm × 8.5 cm size and 159.4 g of weight, considered as a portable device. In the program is selected of function mode: photometer or fluorimeter. In the analytic performance test by photometric mode, were used three solutions amaranth (AM), blue light (AB) and tartrazine (TT). The detection limits obtained were 1.6 × 10−7, 5.4 × 10−7 e 1.9 × 10−6 mol L−1 for AM, AB and TT, respectively. The quantification limits obtained were 4.8 × 10−7, 1.6 × 10−6 e 5.9 × 10−6 mol L−1 for AM, AB and TT, respectively. The correlation coefficients were AM = 0.997, AB = 0.975 and TT = 0.994. The analytic performance for fluorometric mode was carried using in both fluorescein (FL) and Rodamine 6G (R6G) solutions, were obtained a detection limit of 8.3 × 10−8 and 4.79 × 10−8 mol L−1, respectively for FL and R6G. The correlations coefficients were 0.997 for FL and 0.999 for R6G. Also, the proposed device was successfully used to sulphite determination in drinks, total hardness in water, determination of stability constant and study of stoichiometry of a chromogenic complex, aiming to show any applications of photometer/fluorimeter. The constant of formation obtained was 5.04 × 1018 is concordant with that presented in previous reports 6.2 × 1018. In sulphite determinations on eight samples of drinks, the paired studen’s t-test showed that reference method and photometric method using P2FM was 0.66 times smaller than critic value (2.36, α = 0.05). The total hardness in water was determined by fluorometric method, being that the P2FM showed best sensibility 8.94 × 106 that a determination using the RF5301/PC spectrofluorometer. The paired studen’s t-test (α = 0.05) no showed significant differences, calculated t (0.36) small than tabulated t (2.01).
Um fotômetro/fluorímetro microcontrolado (P2FM) multifuncional, portátil, comunicado via USB 2.0, robusto, de fácil operação e com baixo consumo de energia foi desenvolvido neste trabalho. O P2FM foi construído utilizando-se um microcontrolador (PIC-18F2455) como unidade central de processamento (CPU), dois LEDs tricolores (470, 528, 621 nm) como fonte de radiação, um sensor multicanal (TCS3200), e o programa de gerenciamento escrito em Visual Studio. Um dos LED foi utilizado como fonte de radiação para o modo fotométrico e o outro para o modo fluorimétrico. O TCS-3200 é um sensor multicanal com quatro faixas fotossensíveis: 480, 540, 750 e 830 nm, sendo que a seleção da faixa é realizada via programa de controle. O programa de gerenciamento atua no envio de funções para o microcontrolador, registro de dados e armazenamento do sinal (*.txt) através da porta USB 2.0 (5,0 VCC, 300 mA). O P2FM é compacto, com dimensões de 3,5 cm × 7,0 cm × 8,5 cm e massa de 159,4 g, configurando-se um instrumento portátil. No programa é selecionado o modo de funcionamento: fotométrico ou fluorimétrico. Nos testes de desempenho analítico no modo fotométrico foram empregadas soluções dos corantes amaranto (AM), azul brilhante (AB) e tartrazina (TT). Os limites de detecção obtidos foram 1,6 × 10, 5,4 × 107 e 1,9 × 106 mol L1 para AM, AB e TT, respectivamente. Os limites de quantificação obtidos foram 4,8 × 107, 1,6 × 10 e 5,9 × 106 mol L1 para AM, AB e TT, respectivamente. Os coeficientes de correlação foram: AM = 0,997, AB = 0,975 e TT = 0,994. O desempenho analítico no modo fluorimétrico foram realizados empregando-se soluções de fluoresceína (FL) e Rodamina 6G (R6G), sendo obtidos um limite de detecção de 8,3 × 108 e 4,79 × 108 mol L1, respectivamente para FL e R6G. Os coeficientes de correlação foram 0,997 para FL e 0,999 para R6G. Ademais, o instrumento proposto foi aplicado com sucesso na determinação de sulfito em bebidas, dureza total em água e determinação da constante de estabilidade e estequiometria de um complexo cromogênico, objetivando mostrar algumas aplicações do fotômetro/fluorímetro. A constante de formação obtida (5,04 × 1018) está em consonância com aquela apresentada na literatura, 6,2 × 1018. Na determinação de sulfito em oito amostras de bebidas, o teste t-pareado mostrou que método de referência e o método fotométrico usando P2FM foi de 0,66 menor do que o valor crítico (2,36, α = 0,05). A dureza da água foi determinada empregando-se o método fluorimétrico, sendo que o P2FM apresentou melhor sensibilidade 8,94 × 106 que a determinada empregandose o espectrofluorímetro (RF5301/PC). O teste t-pareado (α = 0,05) mostrou que não há diferença significativa, t critico (0,36) menor que o t crítico (2,01).
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Pontes, Aline Santos de. "Desenvolvimento de um fotômetro LED-Vis portátil e microcontrolado por Arduino." Universidade Federal da Paraíba, 2014. http://tede.biblioteca.ufpb.br:8080/handle/tede/7136.
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Previous issue date: 2014-04-28Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
A portable and low-cost photometer is proposed in this work. The instrument uses a tri-color light emitting diode (LED) as its radiation source in maximum emission wavelengths of 480 (blue), 534 (green) and 630 nm (red). It employs a phototransistor with spectral sensitivity in the visible region, as well as an Arduino microcontroller. Its analytical performance was evaluated by means of quantitative analysis (analytical curves), whose models were validated by analysis of variance (ANOVA). The instrument was applied to determine sunset yellow dye in energy drinks and sodas, and potassium permanganate pills. For comparison purposes, a commercial spectrophotometer was used to construct the calibration curves for the reference method. Applying the paired t-test at a 95 % confidence level for the concentration results obtained with the two instruments, we observed no statistically significant difference. Furthermore, accurate concentration estimates were obtained for the analytes as confirmed by the low relative standard deviation range of 0.2 and 0.5%, respectively, for both the dye and the permanganate. The proposed photometer might be an economically viable alternative to spectroscopic analysis, especially in teaching laboratories with limited financial resources or lacking in highly qualified personnel.
Um fotômetro portátil e de baixo custo é proposto neste trabalho. Esse instrumento utiliza um diodo emissor de luz (LED-Light Emitting Diode) tricolor como fonte de radiação nos comprimentos de onda do máximo de emissão de 480 (azul), 534 (verde) e 630 nm (vermelho). Além disso, emprega um fototransistor com sensibilidade espectral na região do visível como fototransdutor, bem como um microcontrolador Arduino como unidade de controle. Seu desempenho analítico foi avaliado por meio de análises quantitativas baseadas em curvas analíticas, cujos modelos foram validados por meio da Análise de Variância (ANOVA). O instrumento foi aplicado à determinação do corante amarelo crepúsculo em amostras de refrigerantes e bebidas energéticas e de permanganato de potássio em amostras de medicamentos. Para fins de comparação, um espectrofotômetro comercial foi empregado para construir as curvas analíticas do instrumento de referência. Aplicando o teste t-emparelhado ao nível de 95% de confiança para os resultados de concentração obtidos com os dois instrumentos, observa-se que não houve diferença estatisticamente significativa. Ademais, resultados precisos nas estimativas das concentrações dos analitos foram obtidos sendo atestado pelo baixo desvio padrão relativo conjunto de 0,2 e 0,5%, respetivamente, para o corante e permanganato. O fotômetro proposto pode ser uma alternativa economicamente viável para análises espectrométricas, sobretudo, em laboratórios de ensino com poucos recursos financeiros e carentes de pessoal altamente qualificado.
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Pham, Huy-Hieu. "Architectures d'apprentissage profond pour la reconnaissance d'actions humaines dans des séquences vidéo RGB-D monoculaires : application à la surveillance dans les transports publics." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30145.
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Cette thèse porte sur la reconnaissance d'actions humaines dans des séquences vidéo RGB-D monoculaires. La question principale est, à partir d'une vidéo ou d'une séquence d'images donnée, de savoir comment reconnaître des actions particulières qui se produisent. Cette tâche est importante et est un défi majeur à cause d'un certain nombre de verrous scientifiques induits par la variabilité des conditions d'acquisition, comme l'éclairage, la position, l'orientation et le champ de vue de la caméra, ainsi que par la variabilité de la réalisation des actions, notamment de leur vitesse d'exécution. Pour surmonter certaines de ces difficultés, dans un premier temps, nous examinons et évaluons les techniques les plus récentes pour la reconnaissance d'actions dans des vidéos. Nous proposons ensuite une nouvelle approche basée sur des réseaux de neurones profonds pour la reconnaissance d'actions humaines à partir de séquences de squelettes 3D. Deux questions clés ont été traitées. Tout d'abord, comment représenter la dynamique spatio-temporelle d'une séquence de squelettes pour exploiter efficacement la capacité d'apprentissage des représentations de haut niveau des réseaux de neurones convolutifs (CNNs ou ConvNets). Ensuite, comment concevoir une architecture de CNN capable d'apprendre des caractéristiques spatio-temporelles discriminantes à partir de la représentation proposée dans un objectif de classification. Pour cela, nous introduisons deux nouvelles représentations du mouvement 3D basées sur des squelettes, appelées SPMF (Skeleton Posture-Motion Feature) et Enhanced-SPMF, qui encodent les postures et les mouvements humains extraits des séquences de squelettes sous la forme d'images couleur RGB. Pour les tâches d'apprentissage et de classification, nous proposons différentes architectures de CNNs, qui sont basées sur les modèles Residual Network (ResNet), Inception-ResNet-v2, Densely Connected Convolutional Network (DenseNet) et Efficient Neural Architecture Search (ENAS), pour extraire des caractéristiques robustes de la représentation sous forme d'image que nous proposons et pour les classer. Les résultats expérimentaux sur des bases de données publiques (MSR Action3D, Kinect Activity Recognition Dataset, SBU Kinect Interaction, et NTU-RGB+D) montrent que notre approche surpasse les méthodes de l'état de l'art. Nous proposons également une nouvelle technique pour l'estimation de postures humaines à partir d'une vidéo RGB. Pour cela, le modèle d'apprentissage profond appelé OpenPose est utilisé pour détecter les personnes et extraire leur posture en 2D. Un réseau de neurones profond est ensuite proposé pour apprendre la transformation permettant de reconstruire ces postures en trois dimensions. Les résultats expérimentaux sur la base de données Human3.6M montrent l'efficacité de la méthode proposée. Ces résultats ouvrent des perspectives pour une approche de la reconnaissance d'actions humaines à partir des séquences de squelettes 3D sans utiliser des capteurs de profondeur comme la Kinect. Nous avons également constitué la base CEMEST, une nouvelle base de données RGB-D illustrant des comportements de passagers dans les transports publics. Elle contient 203 vidéos de surveillance collectées dans une station du métro incluant des événements "normaux" et "anormaux". Nous avons obtenu des résultats prometteurs sur cette base en utilisant des techniques d'augmentation de données et de transfert d'apprentissage. Notre approche permet de concevoir des applications basées sur des techniques de l'apprentissage profond pour renforcer la qualité des services de transport en communThis thesis is dealing with automatic recognition of human actions from monocular RGB-D video sequences. Our main goal is to recognize which human actions occur in unknown videos. This problem is a challenging task due to a number of obstacles caused by the variability of the acquisition conditions, including the lighting, the position, the orientation and the field of view of the camera, as well as the variability of actions which can be performed differently, notably in terms of speed. To tackle these problems, we first review and evaluate the most prominent state-of-the-art techniques to identify the current state of human action recognition in videos. We then propose a new approach for skeleton-based action recognition using Deep Neural Networks (DNNs). Two key questions have been addressed. First, how to efficiently represent the spatio-temporal patterns of skeletal data for fully exploiting the capacity in learning high-level representations of Deep Convolutional Neural Networks (D-CNNs). Second, how to design a powerful D-CNN architecture that is able to learn discriminative features from the proposed representation for classification task. As a result, we introduce two new 3D motion representations called SPMF (Skeleton Posture-Motion Feature) and Enhanced-SPMF that encode skeleton poses and their motions into color images. For learning and classification tasks, we design and train different D-CNN architectures based on the Residual Network (ResNet), Inception-ResNet-v2, Densely Connected Convolutional Network (DenseNet) and Efficient Neural Architecture Search (ENAS) to extract robust features from color-coded images and classify them. Experimental results on various public and challenging human action recognition datasets (MSR Action3D, Kinect Activity Recognition Dataset, SBU Kinect Interaction, and NTU-RGB+D) show that the proposed approach outperforms current state-of-the-art. We also conducted research on the problem of 3D human pose estimation from monocular RGB video sequences and exploited the estimated 3D poses for recognition task. Specifically, a deep learning-based model called OpenPose is deployed to detect 2D human poses. A DNN is then proposed and trained for learning a 2D-to-3D mapping in order to map the detected 2D keypoints into 3D poses. Our experiments on the Human3.6M dataset verified the effectiveness of the proposed method. These obtained results allow opening a new research direction for human action recognition from 3D skeletal data, when the depth cameras are failing. In addition, we collect and introduce in this thesis, CEMEST database, a new RGB-D dataset depicting passengers' behaviors in public transport. It consists of 203 untrimmed real-world surveillance videos of realistic "normal" and "abnormal" events. We achieve promising results on CEMEST with the support of data augmentation and transfer learning techniques. This enables the construction of real-world applications based on deep learning for enhancing public transportation management services
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Tsai, Chi-Chu, and 蔡期竹. "180Hz Stencil-FSC Method With RGBW 4-in-1 LEDs for Color Filter-Less LCDs." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/60156618612917517273.
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碩士國立交通大學
光電工程學系
98
The Global warming issue has become more seriously in recent years. Therefore, how to reduce the speed of earth damage becomes a hot issue in many research areas. In the display area, field-sequential-color (FSC) technology not requiring color filter was proposed to enhance light transmittance of LCDs. It has some advantages like high image resolution, high color gamut, and low material cost. However, FSC technology has a fatal drawback, color breakup (CBU) phenomenon. CBU phenomenon seriously decreases image quality. Therefore, there are some CBU suppression method were proposed. However, those methods also have some issues like low LC response time. Therefore, our group proposed 240Hz, 180Hz Stencil-FSC methods and Two-color-field method to suppress CBU, however, the 180Hz Stencil-FSC method has a minor issue, color distortion. In this thesis, the “adaptive base 180Hz Stencil-FSC method” was proposed to reduce color distortion of 180Hz Stencil-FSC method. By determining the dominant color of first field, the color distortion was much reduced to average ΔE00<1. The relative CBU was reduced to 59% of conventional RGB-FSC method. Furthermore, the adaptive base 180Hz Stencil-FSC method was verified in a 46” 120Hz MVA-LCD and made CBU almost imperceptible. On the other hand, this thesis also proposed RGBW 4-in-1 LEDs backlight system to further reduce the power consumption of FSC-LCDs. The gray/white part of image was generated using high efficiency white-light LED instead of low efficiency RGB LED. The remaining color part was generated using RGB LED. By this way, the power consumption of FSC-LCDs was further reduced. However, the two-color-field method could not reduce power with RGBW 4-in-1 LEDs because there were only two primary colors in each field. Therefore, this thesis modified the algorithm to be 120Hz Stencil-FSC method by making first field become a multi-color single field. Then 240Hz, adaptive base 180Hz, and 120Hz Stencil-FSC methods were applied on RGBW 4-in-1 LEDs backlight system and reduced optical power to 62%, 52%, and 24% of conventional RGB-FSC method respectively. Therefore, the Stencil-FSC method with RGBW 4-in-1 LEDs backlight system provide high image quality with low power consumption.
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Wu, Guo-Yang, and 吳國揚. "Analysis of LED Array of RGB LEDs by Artificial Neural Network." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/12968455321632161681.
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碩士國立雲林科技大學
電子與光電工程研究所碩士班
100
High power light-emitting diodes (HP-LEDs) always are applied for energy-saving to replace the traditional light sources. Therefore, the high power LED lighting has been regarded in the next generation lighting. In this study, we design the LED array of 2 × 3 with the best artificial neural network (ANN) training model to find the optimization of the neural network calculus. Then, one array data of experimental result was used as the basic to forecast the chromaticity coordinate values of the other 16 arrays. The chromaticity coordinates of the 17 groups LED array were measured by the integrating sphere based on the color temperature of D65. The coordinates of the chromaticity would be simulated and discussed by the optical simulation software and the Artificial Neural Network with optimization algorithms. It was the smallest average error than all with the neural algorithm of Levenberg-Marquardt (L.M.) model. Using the L.M. model to train the model and get the error percentage for the 16 arrays to compare on the basic array. Anyway, the least and highest error rate are 0.2272% and 2.028% for 14th array, respectively. The simulation results with neural network training are 1.027% better than 2.141% that of Trace-Pro simulation. 94.12% arrays could reach the standard with the error rate under 2%, but only 35.29% arrays could reach the standard with the error rate under 1%.
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Liao, Chi-nan, and 廖啟男. "Investigation on Operating Characteristics of RGB LEDs." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/jqwn59.
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碩士國立中山大學
電機工程學系研究所
95
This thesis seeks to gain a better understanding on operating characteristics of the three primary color light emitting diode (LED). By applying direct, pulse and sinusoidal currents with dimming function on red, green, and blue LEDs, respectively, the operating characteristics are investigated, including electrical characteristics and their effects on the light efficiency, spectral power distribution, chromaticity on each color LED and the resultant color gamut. The analysis reveals that the illumination characteristics intimately relate to the driving current. LEDs that are driven by pulse currents with pulse-width-modulation (PWM) dimming have less color shift than those driven by direct and sinusoidal currents with amplitude modulation dimming. However, the problematic color shifting is not acceptable when LEDs with pulse current are dimmed at a lower level. Based on the investigation results, a dimming scheme with PWM and pulse- amplitude-modulation (PAM) is proposed to correct the chromaticity and hence to improve the color gamut.
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Hsu, Yu-Wei, and 許煜偉. "White Light Sensing and Mixing of RGB LEDs." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/35885576473099514451.
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碩士國立成功大學
電機工程學系碩博士班
97
The purpose of this thesis is to develop red, green and blue light emitting diode (LED) mixed light driving circuit for the backlight in the liquid crystal display (LCD). Comparing with the cold cathode fluorescent lamp (CCFL) for backlight, LED can make the image more colorful and saturate. The thesis lets eight LED be a string and uses a LED to sense and mix for LED string. First, analyzes the influence of LED brightness intensity versus color sensor circuit and using integrating sphere measurement system to measure the mixing white light of RGB LED forward current in accordance with single chip control circuit. Then, a closed loop buck converter is designed to provide a stable voltage for LED. Besides, stable current circuit can control the forward current of LED. According to the analysis and measurement result, the brightness intensity of LEDs under a specific current ratio would be transfer to the voltage signal by the color sensor circuit. The voltage signal would be send to the single chip control circuit to control the forward current of every LED. Experimental results show that the sensing and mixing can control the forward current of LED under the mixing current.
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Tsai, Yo-Hunmg, and 蔡友煌. "Color Control of RGB LED." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/58422936347529243592.
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碩士明志科技大學
機電工程研究所
98
This thesis presents the color mixing of red, green and blue light emitting diodes (LED).In order to verify the adopted additive color mixing,a MCU-based RGB-LED lamp,which uses an 8-bit microcontroller, HOLTEK 46R24,is built and a miniature fiber optic spectrometer, USB 4000, and accompanied Spectra Suite software produced by Ocean Optics Inc. are used to measure the experimental results. Based on the temperature characteristics of the used red, green and blue LEDs,color deviations arisen from temperature variations are successfully compensated.
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Lin, Hong-Shen, and 林宏森. "RGB LED backlighting optical feedback compensation." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/15251730552257817348.
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Bautista, Meriam Gay, and 梅利安. "Dimmable Multi-Channel RGB LED Driver." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/41938135831591875664.
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碩士國立臺北大學
電機工程學系
101
This paper proposes a dimmable multi-channel Red-Green-Blue (RGB) LED Driver for backlighting and display and applies variable control technique to regulate color mixing. A linear Control DC-DC converter is used to provide the needed constant current for the RGB LEDs. It is designed to provide greater than 25mA constant output current with high accuracy. A PWM control method is used, of which the variable external voltage determines the available brightness levels and has a dimming frequency of 2 kHz. The proposed LED driver system is also able to dim each individual LED color through the dimming controller circuit; for each of the 3 channel per color around 90%, 93% 93% efficiencies for the red, green and blue channels respectively. A digital port was provided for the option of Digital dimming using a microcontroller. A linear current regulator is presented and this can be extended and applied to multiple strings. The temperature coefficient for the red channel is 75.43 ppm/°C and 89.46 ppm/°C for both green and blue channel. This was designed and simulated using 0.35micron TSMC 2P4M 5V technology and the chip area is 2.31x1.48 (mm2).
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Huang, Zhi-Xin, and 黃之新. "The design of small color-mixing elements of RGB LEDs." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/11962957977244187935.
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碩士國立中央大學
光電科學研究所
93
In this paper, we study in the small color-mixing elements.Finally, we propose a new color-mixing device,which can transform the RGB light into the white light equivalently,and we verify the color-uniformity and efficiency.
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Yeh, Wei-Chen, and 葉韋辰. "Spatial MIMO CSK Visible Light Communications with Addressable RGB LEDs." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/wmc5ya.
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碩士國立臺灣大學
資訊工程研究所
107
Addressable RGB LEDs have gained popularity among computer peripherals in recent years due to its compact size, ease of use and low cost. They can be easily powered and controlled with single power supply and microcontroller such as Arduino. Different level of R, G, B intensities can also be assigned to each addressable RGB LED with refresh rate of hundreds of Hz. Despite that the applications of RGB addressable LEDs are currently limited to indicators or decorating light of computer peripherals such as keyboards, headphones and cooling systems, transmission of information with these LEDs is possible with proper design of modulation and format calibration. In this work, a prototype Visible Light Communications system combining multiple addressable RGB LEDs and a camera is built and evaluated. Spatial MIMO and Color Shift Keying are adopted in the system to maximize data rate under the current hardware setting. Performance impacted factors such as temperature and brightness control mechanism of addressable RGB LEDs are also investigated and discussed. Finally, a novel method to address the symbol-mixing issue is proposed by exploiting multiple LEDs. Our system utilizes 4096 colors to represent data symbols and is capable of achieving a data rate of 1.5 kbps with 5 addressable RGB LEDs under 50 frames per second in 6m, less than 20 pixels for region of each LED while achieving symbol accuracy of 95%.
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Wu, Zong-hua, and 吳宗樺. "An RGB-LED Back-Light Driving Circuit." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/4829ez.
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碩士國立中山大學
電機工程學系研究所
95
This thesis proposes a novel driving circuit of the RGB light emitting diodes (LEDs) for the back-light source of the liquid crystal display. In stead of employing three dc-to-dc converters, a fly-back converter with three secondary windings is used to drive RGB-LED light bars. By adjusting the duty-ratio, the fly-back converter provides compromised voltages to RGB-LEDs in accordance with the operating modes of dimming control, so as to retain current magnitudes within the acceptable values. LEDs of three colors are dimmed by regulating the duty-ratios of three active power switches individually. By changing the ratio of the average currents of the three primary color LEDs, the color temperature range of driving can reach the requests of dimming control. As compared with a consumer product using the conventional driving circuit, the proposed circuit is obviously much simpler with less components and a higher efficiency.
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Lai, Shih-Tao, and 賴世道. "Implementation of RGB Mixed LED Backlight Circuit." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/61022110861728633701.
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碩士中原大學
電機工程研究所
95
Abstract Conventionally, multiple cold cathode fluorescent lamps (CCFLs) are required to provide sufficient backlighting for a large-scale of LCD panels. Growing concerns about environmental issues will exhibit the use of CCFLs that contain poisonous mercury. Owing to improvement in long operative life, wider operation temperature range, and the simplicity of driver circuit: work with low and safe voltages, LED has gradually substituted for CCFL as backlight. In this thesis, a LED backlight circuit for a large-scale LCD panel is studied. The design considerations for RGB LED backlighting circuit are discussed in detail. Burst-mode dimming control is designed to achieve the brightness regulation of the backlighting LEDs. A laboratory prototype for the studied RGB LED backlight circuit is implemented and tested. The experimental results of the prototype circuit are shown and discussed to verify the proposed scheme.
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Lin, Yu-Te, and 林育德. "AC/DC integrated RGB LED backlight driver." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/60298945731246619418.
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碩士雲林科技大學
電機工程系碩士班
97
A RGB LED backlight driven by a integrated converter is proposed in the thesis instead of CCFL as a Lcd backlight. A flyback converter with three windings takes place of conventional three DC/DC converter so as to improve the efficiency and to decrease the cost. Series-parallel LEDs is controlled by several constant-current circuits and the brightness modulation can be much find and smooth by adjusting PWM signal. The operation principle, analysis and design of the converter more detail. Experimental results show a prototype for Vin=85~265VAC, 40W, operating at switching frequency of 65KHz to verify the performance of the proposed converter.
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Wang, Guan-Ren, and 王冠仁. "Characteristic Analysis of High Power RGB-LED." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/96160436535201757150.
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碩士和春技術學院
電機工程研究所
95
The operating characteristics of high power RGB-LED are investigated in the thesis, including the effects of the driving current type, something characteristics about electrical and optical, ambient temperature, and used-time. Before conducting experiment, this thesis is aimed at the process of measure, in order to ensure the experimental accuracy, it would obtain the needful procedure of experiment. To observe the RGB-LED characteristics of optical and electrical, this thesis focus on 1W RGB-LED to use the driving way of constant currents and pulse wave currents when control every 50mA interval from 100mA to 350mA and every 10oC interval from ambient temperature 10oC to 70oC. Additionally, in order to observe the RGB-LED characteristics in long used-time, we would deposit the RGB-LED in a chamber and operate at the constant current 350mA, then it would light up long time with the temperature at 40oC, 50oC, 60oC, 70oC, individually, and which is measured every 500 hours. This associated experiment more realize the characteristics of RGB-LED, it would provide the future with foundation of the LED driving cogitation.
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Shiue, Shy-Haw, and 薛世浩. "RGB LED Color Modulation Driving Circuits Design." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/29606632168875145248.
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碩士華梵大學
機電工程學系博碩專班
98
This thesis presents a digital dimming control circuit for RGB LEDs including driver. We simulate the function of RGB colors using FPGA first, then layout the circuit structure by “TSMC 0.35um MIXED MODE (2P4M, 3.3V/5V) process”. Finally, we can achieve the integrated circuit. The digital circuit is simulated by Xilinx Spartan XCS20XL which is 17 bits dimming. We use a method “pulse width modulation (PWM)” to achieve the RGB mixing light. We simulate the analog circuit with Hspice, layout with Laker made by Springsoft Inc., and verify with Calibre DRC（Design Rule Check）、LVS（Layout vs Schematic）、PEX（Post layout extraction）made by Mentor Graphics Corp. The life of light emitting diode will be decreased with rising temperatures it used by a long time. When we make a module for a LED application, the temperature will rise more easily. Besides packages and cooler, we also have to consider whether if the qualities and functions will be changed by the varieties of the temperature. Therefore, we use “Application-Specific Integrated Circuit” to achieve a high speed, stable, and low cost integrated circuit. Keywords：RGB LED、FPGA、PWM、ASIC
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Yang, Zong-Zhen, and 楊宗振. "Study on RGB LED Backlight Driving System." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/79908509970872481866.
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博士國立臺灣科技大學
電機工程系
100
In this dissertation, a digitally-controlled LLC resonant converter for RGB LED backlight driving system is proposed. The LLC resonant topology allows for zero voltage switching (ZVS) of the main switches thereby dramatically lowering switching losses and boosting efficiency. Field color sequential techniques, local dimming control and dynamic bus voltage regulation technologies are then implemented in the proposed system. Using the topology proposed in this dissertation, only one power converter is required to drive the red, green and blue LED strings; therefore the system configuration is very simple. By dividing the backlight into four areas, the backlight brightness of each area can be individually controlled. The output voltage is adjusted by the proposed digital controller so that RGB LED maintains the desired string current. Because the voltage across the linear current regulators in the system is the minimum voltage, the driving system efficiency is maximized. The proposed backlight driving system boasts the advantages of simple circuit structure, improved power efficiency, high contrast ratio and wide color gamut. Finally, experimental results are presented to validate the effectiveness and correctness of the proposed system. According to the experimental results, the presented system can successfully drive the RGB LED backlight module, and the color-mixing, local dimming and bus voltage regulation functions can be achieved.
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Hou, Chih Teng, and 侯智騰. "Liquid Encapsulated RGB-Stack LED Power Module." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/78146842521719835462.
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Chen, Shin-Pin, and 陳世斌. "The Optical Design and Simulation for Direct RGB LEDs Backlight Module." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/5jy36z.
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碩士國立高雄第一科技大學
光電工程研究所
96
The liquid crystal display will soon to replace cathode ray tube display in the near future, because of its slim appearance, light weight, high brightness, high chromaticity and low electricity consumption, etc. Presently, the thickness of backlight module of direct light emitting diode (LED) cannot be further reduced due to the light source of high power white light LED or the mixing white light from red, green, blue (RGB) light LEDs which luminous intensity is mostly similar to Lambertian. Therefore, it requires space in the outward direction to spread white light uniformly. The encapsulating lens on top of LED die is designed to transform the light emitting from the die to the distribution of horizontal direction using the Advanced System Analysis Program (ASAP) optical software in this thesis. Applying LEDs with the encapsulating lens as the light source in different arrangements of RGGB patterns and depth below the diffuse component, the simulations are given of the distribution of luminance, uniformity, color difference and color mixing for an example of 42 inches direct backlight module.
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Ming-HungPan and 潘明宏. "Chromatic Detection for RGB LED Back Lighting Unit." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/25653303261318200411.
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碩士國立成功大學
工程科學系專班
98
The RGB LED light source not only performs high purity monochromatic light and low power consumption, but also conforms to the environmental protection rule of Restriction of Hazardous Substance. It is one of the major developing techniques for flat panel display industries. This thesis utilized different detection methods to detect the chromaticity variation of RGB LED back lighting units, and then analyzed the advantages and disadvantages of them. These methods primarily involved color-meters, portable spectrometers, and normal color digital cameras as basic frameworks for detection. In addition, the linear light source LED light-bars used in back lighting units were used to exhibit the RGB’s three primary colors and six mixed-color modes through different circuit driver methods. We divided the back lighting unit display area into a 3x3 matrix with nine points for chromatic measurement. The color-meter used in this study directly measured the chromaticity at nine points by single-point movement, which was different from the spectral power distributions measured by the spectrometer. The digital camera obtained image information from the complete display area, then extracted the color map distribution data from nine points at once. Finally, the CIE1931 color system and Matlab programs were used to calculate chromaticity. Using data from RGB LED back lighting unit, this study found that the chromatic detection capacities of the three detection methods- evaluated by NTSC standards, were: color-meter 139.86%, spectrometer 108.42%, and color digital camera 70.69%. By using data from the six mixed-light mode, we can determine the sensitivity based on the largest variance detected by the three detection methods facing minimal color changes, the detection methods were ranked in order as: spectrometer 0.065%, color-meter 0.047%, color digital camera 0.014%. Chromaticity and color temperature data were used to confirm that the color digital camera possessed the detection trends of color-meters and spectrometers, which were useful for RGB LED back lighting unit detection, capturing images via the Matlab program, processing multiple points of color data at once, and obtaining chromaticity values more quickly than the single-point movement method.
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Wang, Shih-Yu, and 王士瑜. "Analysis and design for stable mixed light source based on RGB LEDs." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/12226160470309902983.
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碩士國立中興大學
精密工程學系所
98
The subjects of this study are the temperature and plus width modulation (PWM) duty cycle effect on the characteristics of packaged RGB LEDs with silicon, sapphire, and copper alloy substrates. The way to maintain the color coordinates after the color is mixed by RGB LEDs was also proposed. Several experiments show that output power of LEDs decreases with temperature increasing. During rising temperatures from -10 ℃ to 50 ℃, the output power of red LEDs with silicon substrate decreases around 40 %, peak wavelength increases around 7 nm, and relative uv coordinates shifts around 0.021. At the meantime, peak wavelength and color coordinates also shifts by duty cycle of PWM. The peak wavelength of silicon based red LEDs, sapphire based blue LEDs and copper alloy based LEDs increases 2 nm and relative color coordinates of silicon based red LEDs shifts 0.005 during increases of duty cycle from 0.1 to 1.0. From analyzing the temperature and PWM duty cycle characteristics of silicon based red, green, and blue LEDs and sapphire based, copper alloy based green and blue LEDs, we provide a formula for color mixing. It can maintain the shifts of relative color coordinates lower than industrial standard 0.003 and tristimulus value Y which defines as brightness lower than 5 % with dimming level from 0.3 to 1.0 and operating temperatures range from -10 ℃ to 50 ℃.
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Hong-JiLee and 李鴻基. "Mixed RGB LEDs Driving Circuit with Optical Compensation and Digital Dimming Control." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/73275748738303386751.
Full textAbstract:
碩士國立成功大學
電機工程學系
98
The purpose of this paper is to develop a mixed RGB LEDs driving circuit. First, to measures the electric and optical characteristic of RGB LEDs. And based on additive color mixing of color engineering to calculate mixing ratio, in further, utilize the integrating sphere to verify whether RGB three in one LED is mixed white light. Second, implement RGB LEDs backlight driving circuit for LCD Panel. Because RGB LEDs have different operation voltage, need multi-output flyback converter to supply three voltage for RGB LEDs, collocating constant current circuit to achieve accurate current control among RGB LEDs strings. Finally, LED is a semiconductor device so many factors affect its light-emitting characteristics. Photo sensor can be used for optical compensation and peripheral-interface -controller (PIC) is used as a controller. The feedback controller has to maintain the preset flux form each LED to roughly maintain white point.
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Lee, Cheng-Chen, and 李政憲. "Research on PWM Control Circuit Design for Color Temperature of RGB LEDs." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/02482414937814447606.
Full textAbstract:
碩士國立暨南國際大學
光電科技碩士學位學程在職專班
101
Abstract This thesis will mainly focus on discussion of full color LED operating characteristics. Let LEDs use DC Level driving and Pulse Width Modulation, PWM each with two different voltages, currents, and pulse waves, to undergo Blight Dimming at the same time; to analyze electric characteristics and emitting characteristics including: emitting efficiency, spectrum energy, and effects on CCT and CRI. After analysis, differences in LED operating characteristics are affected by driving current. LED with PWM undergoes BL dimming. During analysis of DC Level driving and Pulse Width Modulation, PWM , LED color chromaticity (CCT) and color rendering index (CRI) offset. Thus this thesis propose using Current Control Mode ,Automatic-Current Control Mode and Automatic-Electric Power Control Mode to undergo Blight Dimming experiment, to therefore stabilize LED of CRI ,CCT and LED-related parameter value.
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Hsieh, Min-Hsiu, and 謝明修. "The study of RGB LED variable color temperature light source machine created by combined designs of lens." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/74529616135758550693.
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Al-Saggaf, Abeer. "A Closed-Loop Smart Control System Driving RGB Light Emitting Diodes." Thesis, 2015. http://hdl.handle.net/10754/552732.
Full textAbstract:
The demand for control systems that are highly capable of driving solid-state optoelectronic devices has significantly increased with the advancement of their efficiency and elevation of their current consumption. This work presents a closed-loop control system that is based on a microcontroller embedded system capable of driving high power optoelectronic devices. In this version of the system, the device in the center of control is a high-power red, green, and blue light emitting diode package. The system features a graphical user interface, namely an Android mobile phone application, in which the user can easily use to vary the light color and intensity of the light-emitting device wirelessly via Bluetooth. Included in the system is a feedback mechanism constituted by a red, green, and blue color sensor through which the user can use to observe feedback color information about the emitted light. The system has many commercial application including in-door lighting and research application including plant agriculture research fields.
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Chiu, Bo-Chun, and 邱博鈞. "The study about design and analysis for high efficiency RGB LEDs projection luminaire." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/79575085527078909049.
Full textAbstract:
碩士國立中央大學
光電科學研究所
99
In this thesis, the main object is the design of RGB LEDs projection luminaire. Its color is adjustable, and if using in producing white-light, we can change the CCT. However, the important issues in this luminaire are optical efficiency and color uniformity. Therefore, we will define the method of measuring and analyzing for color uniformity in the thesis. Moreover, we will also discuss each parameters in the luminaire to find the suitable structure. Finally, we design the high efficiency projection luminaire with color-mixing.
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Lee, Wu-Yuan, and 李武原. "Optimize Placement Angles of RGB LEDs for Direct Type Backlight by Genetic Algorithm." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/55112135171617843138.
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碩士中原大學
機械工程研究所
95
This study proposes a novel cone-shaped lens to replace the low light-efficiency diffuser plate to improve the light output efficiency and simultaneously maintain the satisfactory uniformity. The cone-shaped lens is coated as mirror on the outside surface to reflect the light emitting from the LED below the cone. This reflection leads the light from LED to the side of the optical axis, not along with it, and avoids bright spots on the backlight directly. A prototype of LED backlight module with the designed lens is built to verify the simulation results. In this study, the 8.9% increase in cavity efficiency made possible by the combined use of the novel cone-shaped lens. Finally, perform genetic algorithm through Matlab and TracePro, and search for a set of optimal angle placement of LEDs for color uniformity of BLU optimization. Results of simulation for BLU of 55mm by 55mm, the luminance uniformity that can be more than 85%, and the color difference is under 0.015.
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Hung, Chung-Chih, and 洪崇智. "Auto Mixed Light Research for RGB LED Backlight Module." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/26t9k7.
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碩士國立虎尾科技大學
電機工程研究所
96
In this thesis, light emitting diodes with red, green, and blue lights, respectively, are served as the back-light source and employed to generate the three primitive colors that can be adjusted and mixed to realize the output of white light. Attempts to bring out wider range of color space and obtain higher color saturation can, thus, be achieved. With the introduction of a half-bridge converter with power factor correcting function, an isolated-power-driven light-emitting diode is developed. By using the light-mixing and adjustment technique, the power saving and white light stabilizing can be accomplished. Through the experimental observations and quantitative measurements, the features of light-emitting diodes and photo-detectors are found to be susceptible to temperature. Moreover, different photo-detectors experience different degree of change of features for temperature fluctuation. To prevent the output white light from being experienced with color deviation due to temperature effect on the performance of LED, a mixed-light circuit module is developed, by integrating Programmable System on Chip with photo-diode sensor devices, to examine the ambient temperature and feedback voltage level of RGB photo-diodes. Through the usage of mixed-light control circuit module, the corresponding duty cycle of RGB LED can be adjusted, and the stable white light output can, consequently, be achieved. Furthermore, attempts to correct the error produced by photo-detector diode due to temperature are made by the introduction of a temperature sensor. A so-called “Mixed-light and adjustment control module corrector” was implemented to correct temperature modified value. By mixed-light and adjustment control module and calibrating of the corrector, the CIE1931 xy coordinates of output light are in good agreement with the predicted results.
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Hung, Chien-Chung, and 洪健忠. "High Power RGB-LED Model and its Circuit Applications." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/12189294601121264832.
Full textAbstract:
碩士和春技術學院
電機工程研究所
96
The purpose of this thesis is to investigate the optical and electrical characteristics of high power LEDs under different current and ambient temperature. At the same time, Is Spice software is used to build its model and modulize it. In this thesis, integrating sphere system is used to measure the variation of characteristics of 1W RGB-LED, such as luminous flux, dominant wavelength and equivalent resistance, etc., at the driving current from 100mA to 350mA and ambient temperature controlled at 10oC to 70oC. Based on experimental data, a model is built for further verification by practical circuit application after the establishment of such module. The performance of this modulized model is found more accurate through comparison between simulation result and experimental data using a lighting circuit design composed of 5 pieces of 1 W-LED. This finding could provide a reference for future design aiming at high power LED driving circuit to reduce development and design cost.
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Hsieh, Mingyu, and 謝明諭. "Mini/Micro LED Display Module with RGB Full Colorization." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/g874bd.
Full textAbstract:
碩士逢甲大學
自動控制工程學系
107
Mini/Micro-LED display is considered as the most promising one among the products of display technology for next generation. The major advantages are high efficiency, high brightness, high reliability, fast response, and low power consumption. However, it suffers from several limitations, such as mass transfer technology, full colorization, and driver IC. In view of this, this research proposes a Mini/Micro-LED display module with RGB full colorization. The core concept is to produce a white light through integrating the blue LED array and the yellow phosphor film. Furthermore, the color filter was combined to achieve a self-emitting full-color display with RGB dot array. The display module was mainly divided into three parts, including the LED array, electroformed nickel with holes’ structure, and color filter. First of all, the 32×32 LED arrays with the pixel size 200×200 μm2, 100×100 μm2, and 80×80 μm2 are fabricated, simultaneously. After that, the holes and filter fabrication are finished by nickel electroforming and photolithography process. Finally, the three parts of entire display module was integrated by vertical stacking. Based on the above methods, the experimental results show that R, G, and B three color lights are produced, effectively, and the corresponding peak wavelength are 590 nm, 540 nm, 465 nm, respectively. However, the module is limited by the sapphire thickness and the Lambertian light distribution result in the brightness and contrast decreased. In the future, the problems mentioned above can be solved by optimizing the structure design.
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Shen, Chia-Hui, and 沈佳輝. "Design and Fabrication of White-Light Emitters Using RGB Phosphors Excited by UV LEDs." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/31095353761521531927.
Full textAbstract:
碩士國立中興大學
精密工程學系所
95
Abstract Recently, the development of ultraviolet light-emitting diodes (UV-LEDs) to pump red-green-blue (R/G/B) phosphors becomes a promising technique for white LED applications. However, the fabrication process usually needs try-and-error experiments in order to tailor the exact chromaticity coordinate. This thesis has established a computation framework of CIE xy chromaticity coordinate for the white LEDs based on the UV-pumped RGB phosphors. In order to establish the pumping efficiency and emitting spectrum of each phosphor, we have measured the relationship between the excitation power (dominant wavelength: 385 nm) and the phosphor/epoxy mixture ratio. This computation framework can not only predict the CIE xy coordinate but also compute the mixture ratio of the R/G/B phosphors. As a result, an accuracy of ±0.01 can be achieved between the simulation and measured data for the following cases: (0.340,0.350), (0.200,0.200), (0.380,0.350), (0.325,0.275), and (0.300,0.340). The results indicate that the developed computation framework can be successfully used to derive the exact chromaticity coordinate of the white LED products. Under a 20-mA injection current, the white LED presents a conversion efficiency of 3.49 lm/W. It could be attributed to the lower efficiency of UV LED chip and the R/G/B phosphors. Finally, to avoid the residual UV radiation emitted from the white LEDs, an experimental work using the TiO2 absorber was performed in the LED package. An optimum condition was obtained where the residual UV radiation can be reduced by 83 % using a 4% TiO2/epoxy overcoat with a thickness of 150 um.
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Chiu, Chia-hao, and 邱嘉豪. "Color-Temperature Modulation of RGB LEDs and It’s Application of Color-Sequential Pico-Projectors." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/45268182586114439405.
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碩士國立中央大學
光電科學研究所
99
In this thesis, the modulations on LEDs driving current and duration ratio of RGB-LED-array as light source for pico-projector display were proposed. The light source that we use in this study is OSRAM LE ATB S2W. We perform our light source in consideration of three orientations, power consumption, brightness, and color temperature. Two designs for different projection types, low power-consumption and high brightness, are proposed. Both types are designed to achieve color temperature of 6500K. For a low-power-consumption type, the light source is able to supply 47 lm with color temperature of 6530K at only 0.85-watt power consumption. For high-brightness type, 78.08 lm flux output with color temperature of 6700K is achieved at 2.53 W. Only 5 % difference in brightness and 3 % difference in color temperature between design and measurement. Furthermore, we program a computation tool to simplify computations of prominent appropriate RGB duration ratio from inputting different objective color temperature and driving current of each LED. It also shows brightness and color space results.
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Huang, Ming-Wei, and 黃明偉. "The Design of Digital Control System for RGB-LED Backlighting." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/5287w2.
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碩士中原大學
電機工程研究所
98
The objective of this thesis is to design a Digital Control System for RGB-LED backlighting. This study is mainly comprised of software development environment planning, hardware design, and verification of the system functions. The design tools employed for the software include SOC with 8052 MCU, Source-Insight, Keil C, and an ISP Board. The design of hardware involves an RGB-LED array and an RGB-LED driving circuit, in which the electrical design is derived from the requisite specifications whilst involving a designed integrated layout. The control function of the system is produced by SOC with 8052 MCU to produce visible light with full-coloring. Finally, the Digital Control System for the RGB-LED backlighting was verified via the development of an automatic cycling function for the RGB-LED backlighting.
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Lin, Chung-Yi, and 林忠毅. "Study of RGB LED Color Mixing Mechanism for Oral Illumination." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/9pq6cx.
Full textAbstract:
碩士國立中正大學
光機電整合工程研究所
103
This paper studies the detection of oral illumination flashlight lighting, through a flashlight inside the mirror architecture designed to perform the RGB LED color mixing lighting, from past studies typically use color mixing light pipe diffusion sheet and a plurality of optical components such as lenses to complete the color mixing, so we hopes to use the self-developed optical design of stretched the distance mixed light reflective color mixing lighting. By Solidworks modeling and ASAP ray tracing simulation scenarios, lighting placed in front of each one face, face to use for analysis ,project analysis, including illumination, illumination uniformity, color mixed effects. According to the simulation results can be designed to understand the method of the reflecting surface can be simplified and a more uniform illumination, it can achieve the purpose of saving costs, the mixed light lighting can change its color mixing through modulation of the LED luminous intensity in different lighting, so in the future will be for oral illumination medically helpful.
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Lai, Peng-Yu, and 賴鵬宇. "Investigation of Discomfort Glare of RGB LED Billboard at Night." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/55783798744566716363.
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碩士國立臺灣科技大學
色彩與照明科技研究所
101
Mesopic vision is gaining high attention from lighting researchers and industry people re¬cently. Most night-time outdoor and traffic lighting scenarios are belong the mesopic range. As known as the Purkinje effect, the peak of spectral luminous efficiency shifts to the short-wavelength range in mesopic region. Full color RGB LEDs, which are becoming a popular and energy efficient source for dynamic lighting and displaying information, generally have more wide color gamut than conventional lamps for outdoor lighting like high pressure sodium (HPS) lamps. In addition, achromatic and chromatic color stimuli with same luminance are generally different in brightness (or perceived lightness). The brightness of the latter is higher than the former. The phenomena are well-know and identified with the Helmoholz-Kohlrausch effect (H-K effect). Those imply that LEDs have a potential risk over conventional lamps in terms of discomfort glare. In the measurement, we have 108 different kinds of conditions using the full-color LED billboard with nine color photographs, three color gamut, two kinds of background luminance and two groups of ages. Results revealed that there are significant main factor effects of age, saturation, image and gender in twenty subjects for de Boer glare rating scale. There are three significant interaction effects, including age and saturation, age and image, image and gender. Furthermore, we found that different saturation of displayed images will affect glare discomfort score. Post hoc tests indicated that wide-gamut of RGB LED billboard demonstrated the highest de Boer rating scores (Mean100LED = 4.64; Mean069LED = 4.25; Mean033LED = 3.99), with statistically significant differences detected among three gamut settings. For different age groups, the effect of age was significant. The luminance of the background is not significant. This paper presents results from an ongoing study that compares discomfort glare for different color gamut of RGB LED billboard using the de Boer rating scale. The subjective results were also compared with previous discomfort glare equations. Final, the discomfort glare of RGB LED billboard were described to develop a new discomfort glare equation for outdoor at night.
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Huang, Chien-shun, and 黃建順. "Development of Wireless RGB LED Dimming Control Technology Using Tablet." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/50454950974127890772.
Full textAbstract:
碩士國立臺灣科技大學
電機工程系
101
High intensity light emitting diodes (LEDs) are available in an ever-increasing number of general lighting products. In addition to advantages such as higher energy efficiency and longer life, LED lighting also boasts advantages including low profile, compact size, cold temperature operation, fast turn on time and full controllability. For LED lighting applications, lighting control includes dimming and color control offer potential for increased energy efficiency and user satisfaction. On the other hand, tablets are gaining their popularity due to their portability and their ease of use. The tablet users can use a touchscreen to react to what is displayed and to control how it is displayed; therefore is a suitable candidate for home automation. Of all the user interfaces for home automation, touch screens are the most intuitive and easiest to use. In this thesis, a LED lighting control system based on the Bluetooth wireless network is proposed. The presented system includes three RGB LED light bars and one white LED light bar, a lighting control app for tablets and a Bluetooth communication module for remote control. The hardware and software design will be presented in detail. The experimental results show that tablet is a good candidate for home lighting control applications. Moreover, tablet apps enable easy connection; therefore offers advantages include product interoperability, vendor independence, and accessibility to broader markets.
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Sun, Chong-Yuan, and 孫仲元. "Design and Implementation of FPGA-Based RGB LED Dimming Control." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/83203803971251307583.
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碩士南台科技大學
電機工程系
96
This thesis presents the implement and design of FPGA based RGB LED backlight digital control, including dimming control, feedback control and RS-232 baseband control. By using the digital PWM duty cycle to dim the illumination, we can achieve the RGB mixing light source with unique features such as instant color variability, and proposing three kind of RGB LED dimming control circuit. Under the long time use of LED, its part can affect brightness and stability of the color temperature along with the temperature change. The proposed article makes optics feedback on using the photo sensor element, fuzzy controller stabilizing the color of RGB LED backlight color drift phenomenon which under a long usage, produces the feedback voltage of photo sensor element. Finally, through the experiment, it can be demonstrated that the open loop controls RGB LED the color, and closed loop control stabilizes the RGB LED color temperature.