Restauração de imagens do satélite Landsat-7. / Restoration of LANDSAT-7 satellite images.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The techniques of image restoration are oriented for the modeling of the degradation and recovery of the original signal that was degraded during the process of image formation. In Remote Sensing, sensor?s nominal spatial resolution, that defines the precision with which details of objects of interest in the image are perceivable, is one of the most importa nt characteristics. During the process of image generation, the spatial resolution is degraded due to optic diffraction, to detector size, to limitations of the electronic filter, to means of transmission, etc. This degradation makes that the images present a blurred aspect that characterizes the loss of details. A form to evaluate the performance of the sensor, in terms of spatial resolution, is through Effective Instantaneous Field of View parameter (EIFOV) that defines the effective spatial resolution of the sensor. In the on board satellite systems, the values of EIFOV are usually worst then the nominal resolution, which does not take in account the imperfections of the sensor. Using restoration techniques, it is possible to improve the effective resolution of the image up to a certain level. Thus, this work?s proposal is to accomplish an evaluation of the effective resolution of Enhanced Thematic Mapper (ETM+) bands of Landsat-7 satellite, and to implement a restoration method to correct the images generated by this sensor. The model of imaging system of ETM+ sensor, as well as, the factors that contribute for the degradation of its effective spatial resolution are discussed in this work. The restoration algorithm is based on the method of the compensation of transference function of the sensor or on the method of the modified inverse filter. Moreover, the combination of processes of restoration and resampling are used to generate ETM+ images in a finer grid with better visual quality then the images resampled through conventional interpolation filters such as the one of cubic convolution.

ASSUNTO(S)

modulation transfer function (mtf) image processing restoration restauração landsat-7 interpolation função de transferência de modulação (ftm) effective instantaneous field of wiew (eifov) interpolação processamento de imagens

ACESSO AO ARTIGO

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