Análise de modelos digitais de superfície gerados a partir de imagens do sensor PRISM/ALOS

• Autor(a) principal: Oliveira, Leila Freitas de
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3764
• topic: Modelo Digital de Superfície; Correção geométrica; Avaliação de qualidade global e local; Digital surface model; Geometric correction; Assessment of overall quality and local; CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOFISICA::SENSORIAMENTO REMOTO

The purpose of this study is the quality assessment of Digital Surface Models (DSMs) generated from stereo pairs of PRISM/ALOS images, considering aspects regarding different approaches of geometric correction, image matching strategies, grid distance and positional accuracy. The standard of accuracy expected for the products evaluated considers the Technical Standards of the National Cartography, defined by the Cartographic Accuracy Standard of the brazilian systematic mapping for 1:25,000 scale, class A. In the geometric correction step are considered the approaches of rigorous sensor model and generalized model using Rational Polynomial Coefficients (RPCs). The ground control points used in geometric correction and in global assessment of the positional accuracy of orthoimages and DSMs, were determined by GPS relative static positioning. The local assessments, aiming the analysis of DSMs as to different morphologies, are performed from control points determined by relative kinematic GPS positioning in low-slope surfaces and on inclined surfaces. The global results achieved indicate that the geometric modeling, the number of control points considered, as well as the strategies for image matching and grid distance influence the vertical accuracy of the DSM, in relation to the expected accuracy standard. The experiments performed to orthorectify the nadir images using the DSMs previously selected, show that variations as to these factors, beyond different vertical accuracies, not affect the expected horizontal accuracy of the orthoimage, portraying, therefore, the same horizontal quality standard for the MDSs used in the orthorectification. The statistical tests for trend and precision detection, confirm the relative consistency on all orthoimages and MDSs generated. However, most of these products presents trend, except for some isolated cases. As to the local assessment, the results indicate that different morphologies influence the accuracy of the DSM, in relation to global assessment. In general, the results in low-slope areas present greater accuracy. The local analyses also indicate that the slope, associated with factors such as failure image matching and interpolation procedures, provides degradation of DSM vertical accuracy.