Uma análise da infestação por plantas aquáticas utilizando imagens multiescala e redes neurais artificiais
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Data
2005
Autores
Cruz, Narjara Carvalho da [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Nos últimos anos, infestações de plantas aquáticas em reservatórios estão sendo estudadas como um efeito do desequilíbrio causado pela poluição e represamento dos rios. A quantidade excessiva de plantas, conseqüente desse desequilíbrio, dificulta tanto a navegação como a produção de energia elétrica. Esse tipo de ocorrência, assim como a presença de algumas substâncias na água, provocam mudanças na radiância da mesma, registradas por sensores orbitais. Nesse sentido, técnicas de processamento e análise de dados de sensoriamento remoto podem se constituir em uma fonte complementar de dados e fornecer informações relacionadas ao grau de infestação de reservatórios. Nesse contexto, o presente trabalho teve como objetivo verificar a influência da resolução espacial de imagens multiespectrais na detecção e mapeamento de áreas infestadas por plantas aquáticas emersas em um reservatório de pequeno porte, através de utilização de procedimentos de análise multiescala e classificação supervisionada usando redes neurais artificiais. Para isso foram utilizadas imagens IKONOS multiespectrais (4 metros de resolução espacial) do reservatório de Salto Grande localizado na cidade de Americana- SP. Assim, foram geradas imagens multiescala, resultando em imagens de 8, 16 e 32 metros de resolução espacial. Na classificação das imagens, utilizando Redes Neurais Artificiais, os dados de entrada constituíram-se de imagens multiespectrais IKONOS (bandas 1, 2, 3 e 4), imagem de textura (banda do IVP), e uma imagem de índice de vegetação (NDVI). O procedimento metodológico adotado mostrou-se adequado para o mapeamento das variações espectrais da água e detecção das infestações por plantas aquáticas, nos vários níveis de resolução da imagem. Os resultados obtidos mostraram que a classificação pela rede neural, com os parâmetros...
In past few years, great infestations of aquatic plants in reservoirs have been studied as an effect of the environmental unbalance caused by pollution and damming of rivers. The excessive amount of plants, deriving from this unbalance, makes navigation and the production of electricity difficult. This kind of occurrence, as well as the appearance of some substances in the water, cause changes in the water radiance detected by satellite sensors. Thus, processing techniques and data analysis may be used as a complementary data source to give information related to the degree of infestation of these plants in reservoirs. So, the present dissertation aimed at verifying the influence of the spatial resolution of multispectral images in the detection and mapping of areas infested by aquatic plants in a small reservoir , through the use of multiscale analysis procedures and supervised classification using artificial neural networks. Multiespectral imagens IKONOS (spatial resolution of 4 meters) of the reservoir of Salto Grande, in the city of Americana-SP were used. So, multiscale images were generated, resulting in images of 8, 16 and 32 meters of spatial resolution. In the classification of these images, using Artificial Neural Networks, the input data was constituted of multispectral images IKONOS (bands 1, 2, 3 and 4), image of texture (band of NIR), and one image of vegetation index (NDVI). The method used was adequate to map the spectral variation of the water and to detect infested areas of aquatic plants in the various levels of resolution of the image. The results obtained showed that the classification by the parameters defined for the original image and applied in the training of the scheme adopted for the different resolution levels was satisfactory. Furthermore, an analysis was made comparing multiscale images classified through crossed comparison, which permits comparing...(Complete abstract click electronic access below)
In past few years, great infestations of aquatic plants in reservoirs have been studied as an effect of the environmental unbalance caused by pollution and damming of rivers. The excessive amount of plants, deriving from this unbalance, makes navigation and the production of electricity difficult. This kind of occurrence, as well as the appearance of some substances in the water, cause changes in the water radiance detected by satellite sensors. Thus, processing techniques and data analysis may be used as a complementary data source to give information related to the degree of infestation of these plants in reservoirs. So, the present dissertation aimed at verifying the influence of the spatial resolution of multispectral images in the detection and mapping of areas infested by aquatic plants in a small reservoir , through the use of multiscale analysis procedures and supervised classification using artificial neural networks. Multiespectral imagens IKONOS (spatial resolution of 4 meters) of the reservoir of Salto Grande, in the city of Americana-SP were used. So, multiscale images were generated, resulting in images of 8, 16 and 32 meters of spatial resolution. In the classification of these images, using Artificial Neural Networks, the input data was constituted of multispectral images IKONOS (bands 1, 2, 3 and 4), image of texture (band of NIR), and one image of vegetation index (NDVI). The method used was adequate to map the spectral variation of the water and to detect infested areas of aquatic plants in the various levels of resolution of the image. The results obtained showed that the classification by the parameters defined for the original image and applied in the training of the scheme adopted for the different resolution levels was satisfactory. Furthermore, an analysis was made comparing multiscale images classified through crossed comparison, which permits comparing...(Complete abstract click electronic access below)
Descrição
Palavras-chave
Cartografia, Redes neurais (Computação), Plantas aquaticas, Classificação de imagens, Redes Neurais Artificiais, Infestações de Plantas aquáticas, Image Classification, Artificial Neural Networks, Infestations of Aquatic Plants
Como citar
CRUZ, Narjara Carvalho da. Uma análise da infestação por plantas aquáticas utilizando imagens multiescala e redes neurais artificiais. 2005. 99 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências e Tecnologia, 2005.