Orientação exterior de imagens orbitais usando modelos rigorosos com feições retas
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Data
2007-08-31
Autores
Medeiros, Nilcilene das Graças [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O objetivo deste trabalho é o desenvolvimento e avaliação de dois modelos de orientação exterior para sensores de varredura linear (pushbroom) que permitem estimar os coeficientes que descrevem a trajetória da plataforma, ambos utilizando feições retas como controle de campo. Considerando que a aquisição da imagem de varredura linear não é instantânea, devem ser calculados seis Parâmetros de Orientação Exterior (POE) para cada linha adquirida. Para tanto a posição e atitude do sensor são modeladas a partir de um polinômio temporal. A relação de uma reta no espaço imagem e sua homóloga no espaço objeto é estabelecida no primeiro modelo, a partir da equivalência entre o vetor normal ao plano de projeção no espaço imagem e o vetor normal ao plano de projeção no espaço objeto rotacionado. A propriedade de equivalência entre planos foi adaptada para considerar a geometria da imagem de varredura linear. O segundo modelo tem como princípio a ortogonalidade do vetor posição de um ponto da reta no espaço imagem (vetor de visada) e o vetor normal ao plano de projeção que contém essa reta no espaço objeto. Além destes, o modelo de colinearidade usando pontos adaptado ao sensor de varredura linear, também foi implementado a fim de comparar as metodologias. Experimentos com dados simulados correspondentes a uma cena do satélite CBERS (China-Brazil Earth Resource Satellite) e experimentos com dados reais usando uma imagem CBERS foram realizados para testar os modelos desenvolvidos. Os resultados mostraram que os modelos propostos podem ser usados para calcular os POE de imagens de varredura linear, e dispondo de tais parâmetros, a correção geométrica de imagens orbitais pode ser realizada. São analisados ainda, vários fatores determinantes da precisão, como o número e distribuição das entidades de controle.
The aim of this paper is to present the derivation and evaluation of two models for orientation of pushbroom sensors that allow estimating the polynomial coefficients describing the platform trajectory. Both models use only linear features as ground control. Considering that pushbroom image acquisition is not instantaneous, six EOP (Exterior Orientation Parameters) for each scanned line must be estimated. The sensor position and attitude parameters are modeled with a time dependent polynomial. The relationship between a straight line in the image space and its homologous in the object space is established in the first model through a mathematical model based on the equivalence between the vector normal to the projection plane in the image space and the vector normal to the rotated projection plane in the object space. The equivalence property between planes was adapted to consider the pushbroom geometry. The second model rely on the principle that the position vector containing image point (viewing vector) and the normal vector to the projection plane in the object space are orthogonal. The model based on collinearity equations using points adapted to the pushbroom geometry were also implemented aiming at the comparison the methodologies. Experiments with simulated data corresponding to a CBERS scene (China-Brazil Earth Resource Satellite) and experiments with real data using a CBERS image were accomplished in order to test the developed models using straight lines. The obtained results showed that the proposed models can be used to estimate the EOP of pushbroom images with suitable accuracy. Such parameters (EOP) can be used to accomplish the geometric correction of orbital images. Several other factors attesting accuracy like distribution and number of control entities were also evaluated.
The aim of this paper is to present the derivation and evaluation of two models for orientation of pushbroom sensors that allow estimating the polynomial coefficients describing the platform trajectory. Both models use only linear features as ground control. Considering that pushbroom image acquisition is not instantaneous, six EOP (Exterior Orientation Parameters) for each scanned line must be estimated. The sensor position and attitude parameters are modeled with a time dependent polynomial. The relationship between a straight line in the image space and its homologous in the object space is established in the first model through a mathematical model based on the equivalence between the vector normal to the projection plane in the image space and the vector normal to the rotated projection plane in the object space. The equivalence property between planes was adapted to consider the pushbroom geometry. The second model rely on the principle that the position vector containing image point (viewing vector) and the normal vector to the projection plane in the object space are orthogonal. The model based on collinearity equations using points adapted to the pushbroom geometry were also implemented aiming at the comparison the methodologies. Experiments with simulated data corresponding to a CBERS scene (China-Brazil Earth Resource Satellite) and experiments with real data using a CBERS image were accomplished in order to test the developed models using straight lines. The obtained results showed that the proposed models can be used to estimate the EOP of pushbroom images with suitable accuracy. Such parameters (EOP) can be used to accomplish the geometric correction of orbital images. Several other factors attesting accuracy like distribution and number of control entities were also evaluated.
Descrição
Palavras-chave
Cartografia, Orbitas, Orientação de imagens, Pushbroom
Como citar
MEDEIROS, Nilcilene das Graças. Orientação exterior de imagens orbitais usando modelos rigorosos com feições retas. 2007. 183 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências e Tecnologia, 2007.