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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

Pré-processamento digital de imagens obtidas na faixa espectral do infravermelho distante / Digital image processing in the longwave infrared spectral range

Bittencourt, Thiago de Morais Gonçalves 14 September 2012 (has links)
Este trabalho apresenta a pesquisa e desenvolvimento de algoritmos de pré-processamento digital de imagens para câmeras térmicas não refrigeradas na faixa espectral do infravermelho distante. O estudo de câmeras infravermelhas é uma questão estratégica, uma vez que tem aplicações militares, civis e científicas. Este trabalho define a concepção e implementação de algoritmos de pré-processamento de imagem necessários para obter imagens com baixo ruído e alto contraste, tais como: correção de não-uniformidade, substituição de pixels defeituosos, geração de histograma, aumento de contraste e processamento de saída do pixel, com taxa de 30 quadros por segundo, utilizando detector não-resfriado com matriz de plano focal de 320 x 240 pixels. Neste trabalho todos os algoritmos foram implementados em software para se obter resultados rapidamente e, assim, facilitar a validação dos códigos. Foram gerados resultados de caracterização eletro-óptica do sistema montado com indicação das principais figuras de mérito que norteiam o estudo desta tecnologia, tais como: componentes de ruído tridimensionais, potência equivalente de ruído, responsividade e relação sinal-ruído. Os resultados indicam que os algoritmos de pré-processamento de imagem propostos aumentam a qualidade da imagem a ser exibida, e os resultados das figuras de mérito calculadas sobre o vídeo digital mostram que todas as métricas apresentaram resultados satisfatórios. / This work aims to present the research and development of digital image processing algorithms for uncooled LWIR thermal camera in Brazil. The study of an infrared thermal camera is a strategic issue since that has more and more applications in military, judicature, rescue, industry, hospital and science areas. This work describes the design and implementation of all image-processing algorithms required to obtain high-performance images with low noise and high contrast, such as: functions for non-uniformity correction of sensor deficiencies, dead-pixel replacement algorithms, histogram generation, contrast enhancement methods and output pixel processing with frame rate of 30 frames per second based on 320 x 240 Uncooled Focal Plane Array (UFPA). In this work all algorithms was implemented in software to get results quickly and to facilitate the validation of computer codes. There are some results of electro-optical characterization on the assembled system, indicating the main figures of merit that guide the study of this technology, such as: 3D noise components, noise equivalent power (NEP), signal transfer function (SiTF) and noise equivalent temperature difference (NETD). The results indicate that the proposed imageprocessing algorithms increase the quality of the corrected image, and the test results through the digital video of the infrared camera show that all metrics are in accordance with its nominal value.
2

Pré-processamento digital de imagens obtidas na faixa espectral do infravermelho distante / Digital image processing in the longwave infrared spectral range

Thiago de Morais Gonçalves Bittencourt 14 September 2012 (has links)
Este trabalho apresenta a pesquisa e desenvolvimento de algoritmos de pré-processamento digital de imagens para câmeras térmicas não refrigeradas na faixa espectral do infravermelho distante. O estudo de câmeras infravermelhas é uma questão estratégica, uma vez que tem aplicações militares, civis e científicas. Este trabalho define a concepção e implementação de algoritmos de pré-processamento de imagem necessários para obter imagens com baixo ruído e alto contraste, tais como: correção de não-uniformidade, substituição de pixels defeituosos, geração de histograma, aumento de contraste e processamento de saída do pixel, com taxa de 30 quadros por segundo, utilizando detector não-resfriado com matriz de plano focal de 320 x 240 pixels. Neste trabalho todos os algoritmos foram implementados em software para se obter resultados rapidamente e, assim, facilitar a validação dos códigos. Foram gerados resultados de caracterização eletro-óptica do sistema montado com indicação das principais figuras de mérito que norteiam o estudo desta tecnologia, tais como: componentes de ruído tridimensionais, potência equivalente de ruído, responsividade e relação sinal-ruído. Os resultados indicam que os algoritmos de pré-processamento de imagem propostos aumentam a qualidade da imagem a ser exibida, e os resultados das figuras de mérito calculadas sobre o vídeo digital mostram que todas as métricas apresentaram resultados satisfatórios. / This work aims to present the research and development of digital image processing algorithms for uncooled LWIR thermal camera in Brazil. The study of an infrared thermal camera is a strategic issue since that has more and more applications in military, judicature, rescue, industry, hospital and science areas. This work describes the design and implementation of all image-processing algorithms required to obtain high-performance images with low noise and high contrast, such as: functions for non-uniformity correction of sensor deficiencies, dead-pixel replacement algorithms, histogram generation, contrast enhancement methods and output pixel processing with frame rate of 30 frames per second based on 320 x 240 Uncooled Focal Plane Array (UFPA). In this work all algorithms was implemented in software to get results quickly and to facilitate the validation of computer codes. There are some results of electro-optical characterization on the assembled system, indicating the main figures of merit that guide the study of this technology, such as: 3D noise components, noise equivalent power (NEP), signal transfer function (SiTF) and noise equivalent temperature difference (NETD). The results indicate that the proposed imageprocessing algorithms increase the quality of the corrected image, and the test results through the digital video of the infrared camera show that all metrics are in accordance with its nominal value.
3

Properties of metastable linkage NO isomers in Na2[Fe(CN)5NO]·2H2O incorporated in mesopores of silica xerogels

Tahri, Zakaria, Lepski, Robert, Hsieh, Kuan-Ying, Bendeif, El-Eulmi, Pillet, Sebastien, Durand, Pierrick, Woike, Theo, Schaniel, Dominik 07 April 2014 (has links) (PDF)
We study the properties of photoinduced metal–nitrosyl linkage isomers in sodium nitroprusside (SNP) as a function of particle size. By embedding the molecular complex at various concentrations into mesopores of silica xerogels the size of the particles can be adjusted. The ground state is characterized by X-ray diffraction, absorption and infrared spectroscopy. The physical properties of the photoswitched molecules were analysed by steady-state low-temperature absorption, infrared spectroscopy and by nanosecond transient absorption spectroscopy. The electronic structure as well as the activation energies of the metastable linkage isomers are independent of the particle size down to single isolated molecules, indicating that the SNP complexes are quasi-free inside the pores of the gel. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
4

Properties of metastable linkage NO isomers in Na2[Fe(CN)5NO]·2H2O incorporated in mesopores of silica xerogels

Tahri, Zakaria, Lepski, Robert, Hsieh, Kuan-Ying, Bendeif, El-Eulmi, Pillet, Sebastien, Durand, Pierrick, Woike, Theo, Schaniel, Dominik January 2012 (has links)
We study the properties of photoinduced metal–nitrosyl linkage isomers in sodium nitroprusside (SNP) as a function of particle size. By embedding the molecular complex at various concentrations into mesopores of silica xerogels the size of the particles can be adjusted. The ground state is characterized by X-ray diffraction, absorption and infrared spectroscopy. The physical properties of the photoswitched molecules were analysed by steady-state low-temperature absorption, infrared spectroscopy and by nanosecond transient absorption spectroscopy. The electronic structure as well as the activation energies of the metastable linkage isomers are independent of the particle size down to single isolated molecules, indicating that the SNP complexes are quasi-free inside the pores of the gel. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

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