1 |
Estudo de um sistema de medição a laser na análise da textura da superfície gerada por torneamentoMarchiori, Marcelo Mennet January 2013 (has links)
A determinação da rugosidade é parte fundamental para a classificação da qualidade de uma superfície. Assim, iniciou-se este trabalho realizando-se estudos a respeito de seus métodos de medição. Devido à grande adaptabilidade e à velocidade dos métodos a laser, os estudos foram direcionados para estes tipos de técnicas de medição. Verificou-se que esses dispositivos vinculavam-se a sistemas em que o laser refletido era analisado através de sistemas com detectores do tipo CCD, em que a imagem refletida era analisada num todo. Assim, a bibliografia trouxe inspiração para mensurar a rugosidade de uma superfície gerada por torneamento horizontal, a partir da intensidade laser refletida. Propôs-se, então, um método baseado exclusivamente, na intensidade do sinal que era refletido pela superfície em estudo, a contar de uma incidência normal, já que aos autores ressaltavam que quanto maior a rugosidade da superfície menor seria o sinal refletido por ela. O sistema foi montado e sua capacidade de diferenciar distintas rugosidades foi testada. Então foram produzidas amostras com diferentes rugosidades, a fim de se obter uma função que pudesse correlacionar o sinal laser com a respectiva rugosidade (medida esta feita em rugosímetro de agulha). A função de transferência encontrada foi testada em amostras dissemelhantes das que a geraram, com o intuito de comprovar sua eficácia. Amostras fabricadas com ferramentas distintas de corte também foram produzidas e submetidas ao mesmo procedimento. As funções de transferência geradas alcançaram sucesso na previsão da rugosidade em, no máximo, 16,6% dos pontos, considerando uma margem de erro de 20%. A seguir, procurando-se os motivos que pudessem ter causado este percentual, levantou-se a possibilidade de estarem ocorrendo efeitos ópticos capazes de causar interferências devido às irregularidades na superfície. Efeitos capazes de degenerarem o sinal refletido. A comprovação de que o sinal eventualmente poderia estar sendo perturbado aconteceu através de referência bibliográfica e de imagens obtidas por microscopia eletrônica de varredura, em que se pôde observar a existência de estruturas na face das amostras que seriam isolada ou conjuntamente capazes de causar os efeitos citados. / The determination of the roughness is a key for a good classification of a surface. Thereby, the work was started with a study about the roughness measurements methods. Due to the great adaptability and speed of laser methods, the studies were directed to these kinds of measurement techniques. It was observed in the literature that these laser devices were linked to systems where the reflected laser was analyzed by systems with CCD detectors, where the reflected image was entirely analyzed. Hence, the bibliography brought inspiration to measure the surface roughness generated by axial turning from the intensity of the reflected laser. It was proposed then a measurement method exclusively based on the intensity of the signal that was reflected by the surface under study, because the authors noted that as the roughness of surface became bigger as the signal reflected is became smaller. The proposed system has been assembled and ability to distinguish different roughness was tested successfully. Then samples were produced with different roughness in order to obtain a function that would correlate the laser signal with its roughness (this measurement is made by tactile measurement instrument). The transfer function obtained was tested on different samples that generated in order to prove its efficacy. Samples produced with different cutting tools were also produced and subjected to the same procedure. The transfer functions reached a successful prediction of the roughness maximum for 16.6% of the points assuming a margin of error of 20%. So, looking up the reasons that could have caused this percentage we think the possibility as the occurrence of some optical effects that can cause interference due to irregularities on the surface. These optical effects can degenerate the reflected signal. The proof that the signal could possibly be corrupted was made by the bibliographic references and some images obtained by scanning electron microscopy in which they could observe the existence of structures on the sample surfaces that would can be a reason for these effects individually or together.
|
2 |
Estudo de um sistema de medição a laser na análise da textura da superfície gerada por torneamentoMarchiori, Marcelo Mennet January 2013 (has links)
A determinação da rugosidade é parte fundamental para a classificação da qualidade de uma superfície. Assim, iniciou-se este trabalho realizando-se estudos a respeito de seus métodos de medição. Devido à grande adaptabilidade e à velocidade dos métodos a laser, os estudos foram direcionados para estes tipos de técnicas de medição. Verificou-se que esses dispositivos vinculavam-se a sistemas em que o laser refletido era analisado através de sistemas com detectores do tipo CCD, em que a imagem refletida era analisada num todo. Assim, a bibliografia trouxe inspiração para mensurar a rugosidade de uma superfície gerada por torneamento horizontal, a partir da intensidade laser refletida. Propôs-se, então, um método baseado exclusivamente, na intensidade do sinal que era refletido pela superfície em estudo, a contar de uma incidência normal, já que aos autores ressaltavam que quanto maior a rugosidade da superfície menor seria o sinal refletido por ela. O sistema foi montado e sua capacidade de diferenciar distintas rugosidades foi testada. Então foram produzidas amostras com diferentes rugosidades, a fim de se obter uma função que pudesse correlacionar o sinal laser com a respectiva rugosidade (medida esta feita em rugosímetro de agulha). A função de transferência encontrada foi testada em amostras dissemelhantes das que a geraram, com o intuito de comprovar sua eficácia. Amostras fabricadas com ferramentas distintas de corte também foram produzidas e submetidas ao mesmo procedimento. As funções de transferência geradas alcançaram sucesso na previsão da rugosidade em, no máximo, 16,6% dos pontos, considerando uma margem de erro de 20%. A seguir, procurando-se os motivos que pudessem ter causado este percentual, levantou-se a possibilidade de estarem ocorrendo efeitos ópticos capazes de causar interferências devido às irregularidades na superfície. Efeitos capazes de degenerarem o sinal refletido. A comprovação de que o sinal eventualmente poderia estar sendo perturbado aconteceu através de referência bibliográfica e de imagens obtidas por microscopia eletrônica de varredura, em que se pôde observar a existência de estruturas na face das amostras que seriam isolada ou conjuntamente capazes de causar os efeitos citados. / The determination of the roughness is a key for a good classification of a surface. Thereby, the work was started with a study about the roughness measurements methods. Due to the great adaptability and speed of laser methods, the studies were directed to these kinds of measurement techniques. It was observed in the literature that these laser devices were linked to systems where the reflected laser was analyzed by systems with CCD detectors, where the reflected image was entirely analyzed. Hence, the bibliography brought inspiration to measure the surface roughness generated by axial turning from the intensity of the reflected laser. It was proposed then a measurement method exclusively based on the intensity of the signal that was reflected by the surface under study, because the authors noted that as the roughness of surface became bigger as the signal reflected is became smaller. The proposed system has been assembled and ability to distinguish different roughness was tested successfully. Then samples were produced with different roughness in order to obtain a function that would correlate the laser signal with its roughness (this measurement is made by tactile measurement instrument). The transfer function obtained was tested on different samples that generated in order to prove its efficacy. Samples produced with different cutting tools were also produced and subjected to the same procedure. The transfer functions reached a successful prediction of the roughness maximum for 16.6% of the points assuming a margin of error of 20%. So, looking up the reasons that could have caused this percentage we think the possibility as the occurrence of some optical effects that can cause interference due to irregularities on the surface. These optical effects can degenerate the reflected signal. The proof that the signal could possibly be corrupted was made by the bibliographic references and some images obtained by scanning electron microscopy in which they could observe the existence of structures on the sample surfaces that would can be a reason for these effects individually or together.
|
3 |
Estudo de um sistema de medição a laser na análise da textura da superfície gerada por torneamentoMarchiori, Marcelo Mennet January 2013 (has links)
A determinação da rugosidade é parte fundamental para a classificação da qualidade de uma superfície. Assim, iniciou-se este trabalho realizando-se estudos a respeito de seus métodos de medição. Devido à grande adaptabilidade e à velocidade dos métodos a laser, os estudos foram direcionados para estes tipos de técnicas de medição. Verificou-se que esses dispositivos vinculavam-se a sistemas em que o laser refletido era analisado através de sistemas com detectores do tipo CCD, em que a imagem refletida era analisada num todo. Assim, a bibliografia trouxe inspiração para mensurar a rugosidade de uma superfície gerada por torneamento horizontal, a partir da intensidade laser refletida. Propôs-se, então, um método baseado exclusivamente, na intensidade do sinal que era refletido pela superfície em estudo, a contar de uma incidência normal, já que aos autores ressaltavam que quanto maior a rugosidade da superfície menor seria o sinal refletido por ela. O sistema foi montado e sua capacidade de diferenciar distintas rugosidades foi testada. Então foram produzidas amostras com diferentes rugosidades, a fim de se obter uma função que pudesse correlacionar o sinal laser com a respectiva rugosidade (medida esta feita em rugosímetro de agulha). A função de transferência encontrada foi testada em amostras dissemelhantes das que a geraram, com o intuito de comprovar sua eficácia. Amostras fabricadas com ferramentas distintas de corte também foram produzidas e submetidas ao mesmo procedimento. As funções de transferência geradas alcançaram sucesso na previsão da rugosidade em, no máximo, 16,6% dos pontos, considerando uma margem de erro de 20%. A seguir, procurando-se os motivos que pudessem ter causado este percentual, levantou-se a possibilidade de estarem ocorrendo efeitos ópticos capazes de causar interferências devido às irregularidades na superfície. Efeitos capazes de degenerarem o sinal refletido. A comprovação de que o sinal eventualmente poderia estar sendo perturbado aconteceu através de referência bibliográfica e de imagens obtidas por microscopia eletrônica de varredura, em que se pôde observar a existência de estruturas na face das amostras que seriam isolada ou conjuntamente capazes de causar os efeitos citados. / The determination of the roughness is a key for a good classification of a surface. Thereby, the work was started with a study about the roughness measurements methods. Due to the great adaptability and speed of laser methods, the studies were directed to these kinds of measurement techniques. It was observed in the literature that these laser devices were linked to systems where the reflected laser was analyzed by systems with CCD detectors, where the reflected image was entirely analyzed. Hence, the bibliography brought inspiration to measure the surface roughness generated by axial turning from the intensity of the reflected laser. It was proposed then a measurement method exclusively based on the intensity of the signal that was reflected by the surface under study, because the authors noted that as the roughness of surface became bigger as the signal reflected is became smaller. The proposed system has been assembled and ability to distinguish different roughness was tested successfully. Then samples were produced with different roughness in order to obtain a function that would correlate the laser signal with its roughness (this measurement is made by tactile measurement instrument). The transfer function obtained was tested on different samples that generated in order to prove its efficacy. Samples produced with different cutting tools were also produced and subjected to the same procedure. The transfer functions reached a successful prediction of the roughness maximum for 16.6% of the points assuming a margin of error of 20%. So, looking up the reasons that could have caused this percentage we think the possibility as the occurrence of some optical effects that can cause interference due to irregularities on the surface. These optical effects can degenerate the reflected signal. The proof that the signal could possibly be corrupted was made by the bibliographic references and some images obtained by scanning electron microscopy in which they could observe the existence of structures on the sample surfaces that would can be a reason for these effects individually or together.
|
4 |
Исследование работы радиовысотомера с линейной частотной модуляцией над лесной поверхностью : магистерская диссертация / The research of the work of the radioaltimeter with linear frequency modulation over the forest surfaceСмирнов, Н. В., Smirnov, N. V. January 2015 (has links)
The purpose of the current exploration is creation of the mathematical model of different modifications of the underlying surface of the «forest» type.
During the exploration the mathematical model of the beating signal of the altimeter was created. That’s allows to explore facet models of different types of underlying surfaces. The model was designed in the MATLAB system.
As the result of the exploration the mathematical models of the underlying surfaces for different types of forests were created. During the modeling process it was designed two different variants of the model. The first variant corresponded only to the MATLAB system and based on the layers during the modeling process. The second variant is based on the 3D-Max model of the underlying surface with the following processing into the MATLAB system.
The explored variants of the model allows to stress facet parameters during the furtherer exploration of the different types of the underlying surfaces.
The diploma project contains four parts and includes 144 pages, 72 figures, 31 sources, 6 appendixes, 58 formulas. / Целью данной работы является создание математической модели различных модификаций подстилающей поверхности типа лес.
В процессе работы была создана математическая модель сигнала биений радиовысотомера, позволяющая исследовать фацетные модели различных типов подстилающей поверхности. Модель разработана в математическом пакете MATLAB.
В результате исследований созданы математические модели подстилающей поверхности для различных видов лесов. При моделировании поверхности было разработано два подхода. Первый подход использует только программный пакет MATLAB и основан на моделировании наборов фацетов в виде слоев. Второй подход основан на построении требуемой поверхности в программе трехмерной визуализации (3Ds MAX) с дальнейшей обработкой экспортированных данных с помощью разработанной модели в среде MATLAB.
Исследованные подходы моделирования поверхности позволяют изучать различные типы подстилающих поверхностей, акцентируя внимание на разных параметрах фацетов.
Дипломный проект содержит 144 страницы, 72 рисунка, 31 источник, 6 приложений, 58 формул, состоит из четырех глав.
|
5 |
Моделирование процесса обработки сигналов в космических РСА высокого разрешения : магистерская диссертация / Modeling of signal processing in high resolution synthetic aperture radarКурганский, А. А., Kurganski, A. A. January 2015 (has links)
В работе актуализируется цель создания учебного программного приложения, позволяющего моделировать процесс формирования и обработки сигналов в космических РСА высокого разрешения. В ходе работы разработано программное приложение, которое позволяет создать облучаемую сцену земной поверхности и сформировать в зависимости от сцены отраженный сигнал с пользовательскими характеристиками РСА, провести его обработку с целью получения радиоголограмм и радиолокационных изображений. Результатом разработки стало учебное программное приложение, которое позволит магистрам направления «Радиотехника» понять принцип формирования и обработки сигналов в космических РСА высокого разрешения и провести ряд исследований, направленных на изучения особенностей формирования радиолокационных изображений. / Problem of development of educational software application that allows to simulate the process of forming and signal processing in space high-resolution SAR is disclosed. In result software application that allows to create an irradiated scene of earth's surface and to form depending on the scene reflected signal with custom features SAR in order to obtain RF holograms and radar images was developed. The achievement is the educational software application that allows magisters of speciality «Radiotechnics» to understand the principle of formation and signal processing in high-resolution SAR and to perform a series of test aimed at studying the characteristics of radar image .
|
6 |
Ultra-Wideband Imaging System For Medical Applications. Simulation models and Experimental Investigations for Early Breast Cancer & Bone Fracture Detection Using UWB Microwave SensorsMirza, Ahmed F. January 2019 (has links)
Near field imaging using microwaves in medical applications is of great current
interest for its capability and accuracy in identifying features of interest, in
comparison with other known screening tools. Many imaging methods have been
developed over the past two decades showing the potential of microwave imaging
in medical applications such as early breast cancer detection, analysis of cardiac
tissues, soft tissues and bones. Microwave imaging uses non-ionizing ultra wideband (UWB) electromagnetic signals and utilises tissue-dependent dielectric
contrast to reconstruct signals and images using radar-based or tomographic
imaging techniques. Microwave imaging offers low health risk, low operational
cost, ease of use and user-friendliness.
This study documents microwave imaging experiments for early breast cancer
detection and bone fracture detection using radar approach. An actively tuned
UWB patch antenna and a UWB Vivaldi antenna are designed and utilised as
sensing elements in the aforementioned applications. Both UWB antennas were
developed over a range of frequency spectrum, and then characteristics were
tested against their ability for microwave imaging applications by reconstructing
the 3D Inversion Algorithm.
An experiment was conducted using patch antenna to test the detection of
variable sizes of cancer tissues based on a simple phantom consisting of a plastic
container with a low dielectric material emulating fatty tissue and high dielectric
constant object emulating a tumour, is scanned between 4 to 8 GHz with the patch antenna. A 2-D image of the tumour is constructed using the reflected
signal response to visualize the location and size of the tumour.
A Vivaldi antenna is designed covering 3.1 to 10.6 GHz. The antenna is tested
via simulation for detecting bone fractures of various sizes and 2-D images are
generated using reflected pulses to show the size of fracture. The Vivaldi antenna
is optimised for early breast cancer detection and detailed simulated study is
carried out using different breast phantoms and tumour sizes. Simulations are
backed with the experimental investigation with the test setup used for patch
antenna. Generated images for simulations and experimental investigation show
good agreement, and show the presence of tumour with good location accuracy.
Measurements indicate that both prototype microwave sensors are good
candidates for tested imaging applications.
|
7 |
Simulace vícecestného šíření vícestavových modulací / Simulation of multipah propagation of multistate modulationsPolák, Ladislav January 2009 (has links)
The diploma thesis Simulation of Multipath Propagation of Multistate Modulations is focused on the development of an appropriate algorithm in MATLAB environment, which is capable to simulate the impact of the multipath propagation on received signal (error rate) on the basis of given parameters of the transmission channels. Mechanisms and characteristics of the wave propagation in communication environment, types of digital modulations and their most important parameters are described in the first part of this thesis. The second part is focused on the simulation itself. Created GUI (Graphical User Interface) is able to display constellation diagrams of transmitted and received signals, as well as their bit error rate. It is also possible to compare these data with the data of signal, which is passed by a non-fading channel.
|
Page generated in 0.1674 seconds