Armand Lopes

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Edge detection is a fundamental issue in image analysis. Due to the presence of speckle, which can be modeled as a strong, multiplicative noise, edge detection in synthetic aperture radar (SAR) images is extremely difficult, and edge detectors developed for optical images are inefficient. Several robust operators have been developed for the detection of(More)
This paper presents a study of SAR images which aims to demonstrate the capability of radar to identify vegetation types and to determine the vegetation canopy parameters. The investigations, per­ formed on bi-temporal and dual-polarization (HH and VV) X-band SAR images of an agricultural scene, included all the steps involved, from SAR images to(More)
This paper presents an analysis of ENSIVAT advanced synthetic aperture radar data acquired over a Sahelian region located in Mali, West Africa. The considered period is 2004-2005 and includes two rainy seasons. Emphasis is put on two ScanSAR modes, namely, the global monitoring (GM) and the wide swath (WS) modes characterized by spatial resolutions of about(More)
| We here develop optimal criteria for detection and localization of step edges in single look complex (SLC) synthetic aperture radar (SAR) images. By working on complex data rather than intensity images, we can easily take the speckle autocorrelation into account, obtain more accurate estimates of local mean reeectivities, and thus achieve better edge(More)
This paper presents an analysis of leaf-characteristics effects on the microwave emission of land surfaces. In order to simulate these effects, a radiative transfer model is presented. The medium consists of a vegetated layer containing randomly oriented leaves, modeled as elliptic-shaped scatterers, over the ground surface. Radiative transfer equations are(More)