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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Monitoring Physiological Signals Using Camera

January 2016 (has links)
abstract: Monitoring vital physiological signals, such as heart rate, blood pressure and breathing pattern, are basic requirements in the diagnosis and management of various diseases. Traditionally, these signals are measured only in hospital and clinical settings. An important recent trend is the development of portable devices for tracking these physiological signals non-invasively by using optical methods. These portable devices, when combined with cell phones, tablets or other mobile devices, provide a new opportunity for everyone to monitor one’s vital signs out of clinic. This thesis work develops camera-based systems and algorithms to monitor several physiological waveforms and parameters, without having to bring the sensors in contact with a subject. Based on skin color change, photoplethysmogram (PPG) waveform is recorded, from which heart rate and pulse transit time are obtained. Using a dual-wavelength illumination and triggered camera control system, blood oxygen saturation level is captured. By monitoring shoulder movement using differential imaging processing method, respiratory information is acquired, including breathing rate and breathing volume. Ballistocardiogram (BCG) is obtained based on facial feature detection and motion tracking. Blood pressure is further calculated from simultaneously recorded PPG and BCG, based on the time difference between these two waveforms. The developed methods have been validated by comparisons against reference devices and through pilot studies. All of the aforementioned measurements are conducted without any physical contact between sensors and subjects. The work presented herein provides alternative solutions to track one’s health and wellness under normal living condition. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2016
2

Projeto e desenvolvimento de um sistema de medição sem contato aplicado ao processo de torneamento / Design and development of a non contact measurement system applied the process of turning

Silva, Rafael Franklin Alves 14 December 2011 (has links)
Made available in DSpace on 2015-05-08T14:59:34Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1933952 bytes, checksum: 631f48c47124341fd9bdddc854ca8722 (MD5) Previous issue date: 2011-12-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work presents a non contact measurement techniques study on the manufacturing process and the design and development of a non contact measurement system for inspection of diameters of parts during the machining process on the lathe. Amongst the techniques are showed technologies which are based on physical principles of optical, pneumatic, electric or ultrasound. The system developed to this work uses an optical sensor to take the scan on the part and an incremental rotary encoder to monitor the displacement of that one. At the end of the inspection operation, the diameter of the part is indicated on a display and transmitted to the computer to standard RS-232 serial communication. Test with the developed measurement system were realized such in the laboratory like a machine shop environment in order to determine the metrological characteristics of the prototype in different conditions of operation. Based on experiments with non contact measuring system, it presented good repeatability, reproducibility and long term stability. / Este trabalho apresenta um estudo das técnicas de medição sem contato em processo de fabricação e o projeto e desenvolvimento de um sistema de medição sem contato, para inspeção de diâmetros de peças durante o processo de usinagem em um torno mecânico. Dentre as técnicas são apresentadas tecnologias que se baseiam nos princípios físicos da óptica, pneumática, elétrica ou ultra-som. O sistema desenvolvido para esta dissertação utiliza um sensor óptico de presença para realizar a varredura na peça e um encoder rotativo incremental para monitorar o deslocamento do sensor óptico. Ao final da operação de inspeção, o diâmetro do mensurando é indicado em um display e transmitido ao computador pelo padrão de comunicação serial RS-232. Testes com o sistema de medição desenvolvido foram realizados tanto em laboratório quanto no ambiente de uma oficina mecânica, a fim de determinar as características metrológicas do protótipo em condições distintas de operação. Com base nos experimentos realizados com o sistema de medição sem contato, o mesmo apresentou boa repetitividade, reprodutibilidade e estabilidade a longo prazo.
3

Teplotní vlastnosti automobilových zdrojů světla - LED / Thermal properties of automotive light sources - LED

Bárta, Jiří January 2018 (has links)
The aim of this theses is to summarize the basic information about thermal properties of automobile lighting sources. The main topic is a LED diode. A model of a LED diode is going to be created in Inventor. A simulation of Joule's losses will be performed in Ansys Workbench Transient.
4

Método de medição sem contato e reconstrução 3D a partir do foco utilizando processamento e análise de imagens

Barbosa, Jonathas Jeronimo 10 July 2012 (has links)
Made available in DSpace on 2015-05-08T14:59:54Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 6740318 bytes, checksum: 039aeeeb7ab617f3306f6110a5f307b0 (MD5) Previous issue date: 2012-07-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The massive use of mills and hydrocyclones operating in closed circuit, in several great relevance socio-economic industrial applications, checks special importance to the problem of the development of processes and mathematical models returned to the optimization of the circuit. This work presents an investigation about about techniques for reducing the prediction error (approximation by spheres) to increase accuracy in non-contact measurements of particle size of minerals in order to increase the effciency of classiffcation by hydrocyclones. Computational methods for counting and measuring particles were developed and implemented, in order to compare the computational vision and particle size separation sieving methods. The proposed method also deals with 3D reconstruction of the particles based on the measurement of their heights. To this goal, a stack of images with variable focus is captured. From this stack calculate the average particle size (estimated from the z axis), display the pictures of the stack through the focus index and the image height. An estimate of the average height of the particles is done and than approximate the shape of the particles (spheroids) and comparison with the results approximating a sphere. Measuring instruments have been adapted for the acquisition of images and also for estimating the height of the particles of the samples. / A utilização massiva de moinhos e hidrociclones operando em circuito fechado, em diversas aplicações industriais de grande relevância sócioeconômica, confere especial importância ao problema do desenvolvimento de processos e modelos matemáticos voltados à otimização do circuito de cominuição-classificação. Este trabalho apresenta uma investigação sobre técnicas para redução do erro de predição (aproximação por esferas) em medições sem contato visando aumentar a exatidão na granulometria de minérios com o intuito de aumentar a eficiência de classificação por hidrociclonagem. Métodos computacionais para contagem e mensuração de partículas foram desenvolvidos e implementados, com vistas a comparar a visão computacional ao método de separação de partículas por peneiramento. O método proposto trata, também, da reconstru ção 3D das partículas baseado na medida de suas alturas. Para tanto, uma pilha de imagens com foco variável é capturada. A partir desta pilha calcula-se a altura mé- dia das partículas (estimativa do eixo Z), exibem-se as imagens da pilha completamente em foco e a imagem de índices de alturas. De posse da estimativa da altura média das partículas é feita a aproximação da forma das partículas (esferóides) e a comparação com os resultados da aproximação por esferas. Instrumentos de medição foram adaptados para aquisição das imagens e também para estimar a altura das partículas das amostras.
5

Electromagnetic digital actuators array : characterization of a planar conveyance application and optimized design / Réseau d’actionneurs électromagnétiques numériques : caractérisation d’une application de type convoyage et conception optimisée

Huyan, Pengfei 27 March 2015 (has links)
Dans les systèmes mécaniques ou mécatroniques, les actionneurs sont les composants utilisés pour convertir l’énergie d’entrée, généralement l’énergie électrique, en tâche mécanique telles que le mouvement, la force ou une combinaison des deux. Actionneur analogique et actionneur numérique sont les deux types d’actionneurs les plus communs. Les actionneurs numériques possèdent les avantages du contrôle en boucle ouverte, faible consommation d’énergie par rapport aux actionneurs analogiques. Cependant, les actionneurs numériques présentent deux inconvénients majeurs. Les erreurs de fabrication de ces actionneurs doivent être contrôlées précisément parce que, contrairement à des actionneurs analogiques, une erreur de fabrication ne peut pas être compensée par la loi de commande. Un autre inconvénient est leur capacité à réaliser les tâches continues en raison de leur corse discrète. Un assemblage de plusieurs actionneurs numériques peut néanmoins réaliser des tâches multiples discrètes. Cette thèse porte sur la caractérisation et l’optimisation d’une conception expérimentale actionneurs tableau numériques pour l’application planaire de transport. Le premier objectif principal de la présente thèse est axé sur la caractérisation de l’ensemble des actionneurs existants et aussi une application planaire de transport sur la base du tableau des actionneurs. A cette fin, une modélisation de la matrice des actionneurs essais expérimentaux ont été effectués afin de déterminer l’influence de certains paramètres sur le comportement des actionneurs de tableau. Le deuxième objectif est de concevoir une nouvelle version du tableau actionneurs sur la base de l’expérience du premier prototype. Une optimisation de la conception a ensuite été réalisée en utilisant des techniques d’algorithmes génétiques tout en tenant compte de plusieurs critères. / In mechanical or mechatronical systems, actuators are the components used to convert input energy, generally electrical energy, into mechanical tasks such as motion, force or a combination of both. Analogical actuator and digital actuator are two common types of actuators. Digital actuators have the advantages of open-loop control, low energy consumption and etc compared to analogical actuators. However, digital actuators present two main drawbacks. The manufacturing errors of these actuators have to be precisely controlled because, unlike to analogical actuators, a manufacturing error cannot be compensated using the control law. Another drawback is their inability to realize continuous tasks because of their discrete stroke. An assembly of several digital actuators can nevertheless realize multi-discrete tasks. This thesis focuses on the experimental characterization and optimization design of a digital actuators array for planar conveyance application. The firs main objective of the present thesis is focused on the characterization of the existing actuators array and also a planar conveyance application based on the actuators array. For that purpose, a modeling of the actuators array and experimental test has been carried out in order to determine the influence of some parameters on the actuators array behavior. The second objective is to design a new version of the actuators array based on the experience of the first prototype. An optimization of the design has then been realized using genetic algorithm techniques while considering several criteria.
6

Digital State Models for Infrastructure Condition Assessment and Structural Testing

Lama Salomon, Abraham 10 February 2017 (has links)
This research introduces and applies the concept of digital state models for civil infrastructure condition assessment and structural testing. Digital state models are defined herein as any transient or permanent 3D model of an object (e.g. textured meshes and point clouds) combined with any electromagnetic radiation (e.g., visible light, infrared, X-ray) or other two-dimensional image-like representation. In this study, digital state models are built using visible light and used to document the transient state of a wide variety of structures (ranging from concrete elements to cold-formed steel columns and hot-rolled steel shear-walls) and civil infrastructures (bridges). The accuracy of digital state models was validated in comparison to traditional sensors (e.g., digital caliper, crack microscope, wire potentiometer). Overall, features measured from the 3D point clouds data presented a maximum error of ±0.10 in. (±2.5 mm); and surface features (i.e., crack widths) measured from the texture information in textured polygon meshes had a maximum error of ±0.010 in. (±0.25 mm). Results showed that digital state models have a similar performance between all specimen surface types and between laboratory and field experiments. Also, it is shown that digital state models have great potential for structural assessment by significantly improving data collection, automation, change detection, visualization, and augmented reality, with significant opportunities for commercial development. Algorithms to analyze and extract information from digital state models such as cracks, displacement, and buckling deformation are developed and tested. Finally, the extensive data sets collected in this effort are shared for research development in computer vision-based infrastructure condition assessment, eliminating the major obstacle for advancing in this field, the absence of publicly available data sets. / Ph. D.
7

Measurement of range of motion of human finger joints, using a computer vision system

Ben-Naser, Abdusalam January 2011 (has links)
Assessment of finger range of motion (ROM) is often required for monitoring the effectiveness of rehabilitative treatments and for evaluating patients' functional impairment. There are several devices which are used to measure this motion, such as wire tracing, tracing onto paper and mechanical and electronic goniometry. These devices are quite cheap, excluding electronic goniometry; however the drawbacks of these devices are their lack of accuracy and the time- consuming nature of the measurement process. The work described in this thesis considers the design, implementation and validation of a new medical measurement system utilized in the evaluation of the range of motion of the human finger joints instead of the current measurement tools. The proposed system is a non-contact measurement device based on computer vision technology and has many advantages over the existing measurement devices. In terms of accuracy, better results are achieved by this system, it can be operated by semi-skilled person, and is time saving for the evaluator. The computer vision system in this study consists of CCD cameras to capture the images, a frame-grabber to change the analogue signal from the cameras to digital signals which can be manipulated by a computer, Ultra Violet light (UV) to illuminate the measurement space, software to process the images and perform the required computation, a darkened enclosure to accommodate the cameras and UV light and to shield the working area from any undesirable ambient light. Two calibration techniques were used to calibrate the cameras, Direct Linear Transformation and Tsai. A calibration piece that suits this application was designed and manufactured. A steel hand model was used to measure the fingers joint angles. The average error from measuring the finger angles using this system was around 1 degree compared with 5 degrees for the existing used techniques.
8

Estudo e aplicação de medição com câmera de vídeo em máquinas de medição por coordenadas

Silva, Marlio Antonio da 26 January 2017 (has links)
Submitted by Maike Costa (maiksebas@gmail.com) on 2017-06-06T11:51:16Z No. of bitstreams: 1 arquivototal.pdf: 3218304 bytes, checksum: ceed68b62fab16215d2955936b2afcf1 (MD5) / Made available in DSpace on 2017-06-06T11:51:16Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3218304 bytes, checksum: ceed68b62fab16215d2955936b2afcf1 (MD5) Previous issue date: 2017-01-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / It is evident that with the increasing advance of the manufacturing industry there is a need for an efficient quality control that meets this demand produced within an increasingly shorter period of time. As a result of this, Coordinate Measuring Machines (CMMs) are widely used for inspection of various components in the current industry, in addition to having the Computer Numeric Control (CNC) - which makes the measurement process much faster than conventional methods - can still measure numerous geometries, since they have several sensors that are suitable for various situations, therefore, there is hardly a configuration that the CMM can’t measure. Measurements made by a CMM can be divided into two groups: contact measurements and non-contact measurements. Contact measurements use the touch sensor, known as a probe, which collects coordinate points on the measured piece with the sensor deflection when touching. Non-contact measurements can be performed with the laser sensor or a digital camera. The present work of master dissertation aims to present some applications of non-contact measurements with the use of a CMM, which incorporates a Charge-Coupled Device (CCD) camera, in components such as fuel injectors nozzles, printed circuit boards and sphere of high accuracy, since these elements have geometries with dimensions less than 4 mm, making it impossible to measure with the use of the conventional contact measurement system. / É evidente que com o crescente avanço da indústria manufatureira exista a necessidade de um controle de qualidade eficiente, que atenda essa demanda produzida dentro de um espaço de tempo cada vez mais curto. Em função disto, as Máquinas de Medição por Coordenadas (MMC) são amplamente empregadas para inspeção de diversos componentes na indústria atual, pois além de contarem com o Comando Numérico Computacional (CNC) – o que torna o processo de medição muito mais rápido do que os métodos convencionais - podem ainda medir inúmeras geometrias, uma vez que dispõem de diversos sensores que são adequados para várias situações, por conseguinte, dificilmente haverá uma configuração que a MMC não possa medir. As medições efetuadas por uma MMC podem ser dividas em dois grandes grupos: as medições por contato e as medições sem contato. As medições por contato utilizam o sensor de toque, conhecido como apalpador, que coleta pontos coordenados na peça medida com a deflexão do sensor quando houver o toque. As medições sem contato podem ser realizadas com o sensor laser ou uma câmera digital. O presente trabalho de dissertação de mestrado tem como finalidade apresentar algumas aplicações de medições sem contato com a utilização de uma MMC, que incorpora uma câmera CCD (Charge-Coupled Device), em componentes como bicos injetores de combustível, placas de circuito impresso e esferas de alta exatidão, visto que esses elementos apresentam geometrias com dimensões inferiores a 4 mm, impossibilitando medições com o uso do sistema de medição por contato convencional.
9

Adaptation de la méthode de projection de franges pour la mesure du relief de grands objets et pour la modélisation anthropométrique : application à l'étude de flotteurs sous pression et au suivi de pathologie de l'abdomen / Fringes projection adaptation for large object dimension measurement and anthropometrical modelling : application to the study of floats and the folluw-up of abdomina pathology

Leandry, Ismaëlle 12 November 2012 (has links)
L'étude proposée porte sur l'adaptation d'une méthode de mesure optique à lamesure de la topologie d'objet de grandes dimensions et à une distance de travail proche. Laméthode optique utilisée est la projection de franges car elle permet l'étude de grands objets.Dans un premier temps, des essais expérimentaux ont été réalisés pour évaluer l'exactitudedu développement actuel ; ce dernier utilisant une analyse de franges s'appuyant sur lacombinaison d'une méthode quasi-hétérodyne utilisant une transformation de Fourier etd'une méthode de code gray.Après avoir quantifié les erreurs et déterminé leurs sources, le choix dudéveloppement d'une procédure d'étalonnage et de nouvelles équations associées à cetteprocédure se sont imposés. Le nouvel étalonnage est quant à lui basé sur une interpolationpolynomiale de points définissant un volume de grandes dimensions. Un objet étalon a étéspécialement conçu pour cette procédure de calibration. Pour évaluer l'erreur du à lacalibration, une étude systématique de cas de polynômes dont le plus haut degré varie de 1à 4 a été effectué. Cette approche a permis de déterminer le degré optimal du polynôme àutiliser. Dans le meilleur cas, l'estimation de l'erreur a permis d'évaluer la précision del'étalonnage à 1 mm sur un objet de 2 m évalué à une distance de 2 m.La méthode a été par la suite appliquée, dans un cadre industriel à l'étude deflotteurs et dans un cadre médical à l'étude du relief de la paroi abdominale. D'un point devue médical, cette méthode permet d'obtenir rapidement et facilement la morphologie ducorps humain. Elle permet aussi d'effectuer un meilleur suivi des pathologiesmorphologiques des patients. / The proposed study deals with the adaptation of an optical method to themeasurement of large objects at a low working distance. The optical method used is thefringe projection technique allowing the study of large objects. At first, experimental trials hasbeen used to evaluate the accuracy of the actual development combining the phase shiftingmethod using a Fourier transform and the gray code technique.When the errors have been quantified and their origins determined, the developmentof a calibration procedure and new associated equations have been chosen. The newcalibration is based on polynomial interpolation of points defining a volume of largedimensions. A tested object was designed specifically for this calibration procedure. Toestimate the calibration error, a systematic study of polynomials cases is performed. Thehighest degree of those cases varies from 1 to 4. This approach allows the determination theoptimal polynomial degree to be used. In the best case, the estimation of the error allows theevaluation of the calibration accuracy of about 1 mm for an object of 2 m large, measured ata distance of 2 m.The method has been subsequently applied, in an industrial setting, to the study offloats and in a medical setting to the study of the relief of the abdominal wall. From a medicalpoint of view, this method gives a rapid and easy access to the topology of human body. Itallows a better follow-up of the patient pathology.
10

Teplotní vlastnosti automobilových zdrojů světla - Halogenové zdroje / Thermal properties of automotive light sources - Halogen sources

Hlubinka, David January 2017 (has links)
The aim of master´s thesis is to get acquainted with the design and materials used in selected automotive light source – tungsten halogen lamp. Further, the thesis focused on the theory and appropriate selection of the thermal measurement method on a real sample. Subsequently, a model of the light source and its simulation in the ANSYS – Maxwell 3D and Mechanical programs are created. Finally, the results of the thermal simulation and the non-contact measurement of the tungsten halogen lamp are evaluated

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