This paper outlines the operational feasibility of very early ERS SAR based acreage estimation of non-agriculture land (set-aside, fallow) and economically important crops in Europe, already during the winter season. To achieve this goal,... more
This paper outlines the operational feasibility of very early ERS SAR based acreage estimation of non-agriculture land (set-aside, fallow) and economically important crops in Europe, already during the winter season. To achieve this goal, a novel method for SAR time-series classification and interpretation has been developed. Results of a real-time ERS experiment are presented. Such results have been used for
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A new segmentation method is applied to different types and combinations of optical data and radar data over an agricultural area. The images, which were of different resolution, have been co-registered in order to make a qualitative... more
A new segmentation method is applied to different types and combinations of optical data and radar data over an agricultural area. The images, which were of different resolution, have been co-registered in order to make a qualitative comparison of the segmented data possible. Comparison of the segmentation results on optical and radar images is done using ground truth for certain crops
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Spatial estimators originating from the local autocorrelation functions (ACF) are introduced into the Gamma-Gamma MAP single-point speckle filter for SAR images in order to account for the effects of speckle and scene spatial correlation,... more
Spatial estimators originating from the local autocorrelation functions (ACF) are introduced into the Gamma-Gamma MAP single-point speckle filter for SAR images in order to account for the effects of speckle and scene spatial correlation, to enhance scene texture, and to preserve the spatial resolution in the restored image. To this end, these estimators are used for the evaluation of the
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The information content of usual SAR data is mainly contained in the radiometric polarization channels i.e. the four Iu, Iw Ihv and 1.h backscattered intensities. For polarimetric data, additional information 1s contained in the extrema... more
The information content of usual SAR data is mainly contained in the radiometric polarization channels i.e. the four Iu, Iw Ihv and 1.h backscattered intensities. For polarimetric data, additional information 1s contained in the extrema of the degree of polarization (l). In the case of clutter, polarimetric information is given by the four complex degrees of coherence, from which the
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Abstract The Maximum A Posteriori (MAP) approach for speckle filtering uses an appropriate speckle model and a Gaussian scene modelisation. Effects of the speckle model and the use of local statistics in the filtering process are... more
Abstract The Maximum A Posteriori (MAP) approach for speckle filtering uses an appropriate speckle model and a Gaussian scene modelisation. Effects of the speckle model and the use of local statistics in the filtering process are analysed. More realistic texture models are ...
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A radiometric and textural per-pixel segmentation method for single channel SAR images is proposed, which takes explicitly into account the probability density function of the imaged scene. This method makes an extensive use of adaptive... more
A radiometric and textural per-pixel segmentation method for single channel SAR images is proposed, which takes explicitly into account the probability density function of the imaged scene. This method makes an extensive use of adaptive preprocessing methods (gamma-gamma MAP speckle filtering, features detection by the ratio detectors, local statistics refined computation), in order to ensure good classification accuracy as well
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ABSTRACT The usefulness of SAR images to detect geological features has been widely demonstrated by numerous studies. Nevertheless, when applied to SAR images, lithologies classification algorithms and pattern recognition tools intended... more
ABSTRACT The usefulness of SAR images to detect geological features has been widely demonstrated by numerous studies. Nevertheless, when applied to SAR images, lithologies classification algorithms and pattern recognition tools intended for the extraction of features of interest are often unable to separate correctly actual geological features from artefacts due to speckle microtexture. The objective of this paper is twofold. The authors first demonstrate that appropriate preprocessing by an advanced tool like the gamma-gamma MAP features retaining an adaptive speckle filter makes the discrimination of lithologies both easier for photo-geologists and possible for automatic classifiers. Next, the combined use of X- and C-band data allow the authors to show how their different sensitivity enhances both discrimination of lithologies and identification of geological features
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ABSTRACT The spatial statistics in a SAR (synthetic aperture radar) image is an important parameter for the classification of different targets, in two respects: it can be an additional discriminant and it can be used as the basis in... more
ABSTRACT The spatial statistics in a SAR (synthetic aperture radar) image is an important parameter for the classification of different targets, in two respects: it can be an additional discriminant and it can be used as the basis in speckle filtering techniques. The authors survey some statistical image models presented in the literature, and then focus on the experimental characterization of the spatial statistics in SAR imagery. Experimental data acquired by the JPL AIRSAR multifrequency polarimetric SAR sensor within the MAESTRO-1 and MAC-Europe campaign, as well as the ESA ERS-1 data are used in the study. MAESTRO 1 was a campaign flown in 1989 and jointly funded by ESA and the CEC JRC Ispra. MAC was a multisensor airborne campaign organized by NASA in 1991. The authors characterize texture in an intensity image by 2 parameters (first order and second order statistics): the alpha parameter in the K distribution, the autocorrelation function. Methods are presented to estimate experimentally these parameters. The parameters are studied for different types of targets and as a function of other parameters, such as polarization, frequency band, viewing direction, multilook processing, spatial resolution
ERS-1 acquisitions of the Black Forest test site in Germany from 1991 to 1993 were selected to cover a variety of seasonal and phenological stages. Multisensor analysis (ERS-1, SPOT) was performed using a forestry GIS data base from the... more
ERS-1 acquisitions of the Black Forest test site in Germany from 1991 to 1993 were selected to cover a variety of seasonal and phenological stages. Multisensor analysis (ERS-1, SPOT) was performed using a forestry GIS data base from the regular forest taxation. It turned out that the C-VV band of ERS-1 is sensitive to age in young deciduous and coniferous forest stands of temperate zones. A synergetic relationship between optical and microwave data has been established. The combined data set provided a combination that allowed better differentiation of forest age classes, as compared to results obtained with the individual sensors
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Ideally, using SAR data in combination with optical data or to invert a physical backscattering model, prior scene knowledge is introduced in adaptive speckle filters in order to restore radar reflectivity i.e. of the physical quantity,... more
Ideally, using SAR data in combination with optical data or to invert a physical backscattering model, prior scene knowledge is introduced in adaptive speckle filters in order to restore radar reflectivity i.e. of the physical quantity, proportional to the backscattering coefficient, that is measured by a SAR instrument. Introduction of a priori knowledge or a priori guess implies generally the
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Most of the processing/analysis tools for SAR images, and particularly the most usual speckle filters, are based on the use of first order local statistics (local mean and local variance). In order to account for the effects due to the... more
Most of the processing/analysis tools for SAR images, and particularly the most usual speckle filters, are based on the use of first order local statistics (local mean and local variance). In order to account for the effects due to the spatial correlation of both the speckle and the scene in SAR images, estimators originating from the local autocorrelation functions (ACF)
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ABSTRACT The usefulness of SAR images to detect geological features has been widely demonstrated by numerous studies. Nevertheless, when applied to SAR images, lithologies classification algorithms and pattern recognition tools intended... more
ABSTRACT The usefulness of SAR images to detect geological features has been widely demonstrated by numerous studies. Nevertheless, when applied to SAR images, lithologies classification algorithms and pattern recognition tools intended for the extraction of features of interest are often unable to separate correctly actual geological features from artefacts due to speckle microtexture. The objective of this paper is twofold. The authors first demonstrate that appropriate preprocessing by an advanced tool like the gamma-gamma MAP features retaining an adaptive speckle filter makes the discrimination of lithologies both easier for photo-geologists and possible for automatic classifiers. Next, the combined use of X- and C-band data allow the authors to show how their different sensitivity enhances both discrimination of lithologies and identification of geological features
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Presents some results of a study carried out in the MTV (Monitoring of the Tropical Vegetation) unit of the Institute for Remote Sensing Applications at the JRC Ispra in the context of the TREES project (Tropical Ecosystem Environment... more
Presents some results of a study carried out in the MTV (Monitoring of the Tropical Vegetation) unit of the Institute for Remote Sensing Applications at the JRC Ispra in the context of the TREES project (Tropical Ecosystem Environment observations by Satellites). The goal of the study is to reach a physical interpretation of the observed time and space changes in
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For surfaces satisfying the “product model”, the sample covariance matrix (CM) is the product of a positive scalar random variable μ representing texture and a mean CM representing the polarimetric properties of the surface. The maximum... more
For surfaces satisfying the “product model”, the sample covariance matrix (CM) is the product of a positive scalar random variable μ representing texture and a mean CM representing the polarimetric properties of the surface. The maximum likelihood (ML) estimator of μ is given by the multilook polarimetric whitening filter (MPWF). The ML estimator satisfies the well known multiplicative speckle model.
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ABSTRACT It is among the basic principles of physical measurement that changing the conditions of measure results in improving the knowledge of the observed phenomena of interest. In remote sensing this is achieved in the case of... more
ABSTRACT It is among the basic principles of physical measurement that changing the conditions of measure results in improving the knowledge of the observed phenomena of interest. In remote sensing this is achieved in the case of multispectral optical data using wavelength diversity. In the the case of single band ERS-1 data the action of external factors (meteorological, phenological, land practices) have an analogous discriminant effect considering multitemporal data. Improvement of extraction of agricultural information is performed using appropriate preprocessing, standardized principal component analysis, and classification using maximum entropy based method, in order to estimate crops acreage. The experiment, conducted over the great Driffield MARS project test site (ERS-1 data from November 1992 to may 1993) shows that set aside land can be identified as early as in February, and that acreage estimation can be done in may for the most important crop types
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Research Interests: Remote Sensing, Agricultural Development, Data Analysis, Carbon Cycle, Image Classification, and 14 moreSeasonality, Image Filtering, Error Analysis, Oil palm, Supervised Classification, High Temperature, Spectrum, Infrared, Secondary Forest, Plant Regeneration, Early Terrestrial Ecosystems, Oil Palm, Vegetation Cover, and Vegetation Mapping
The authors evaluate how fully polarimetric maximum a posteriori (MAP) speckle filters preserve the polarimetric power and texture signatures of textured targets. To this aim, such signatures are quantitatively compared to their... more
The authors evaluate how fully polarimetric maximum a posteriori (MAP) speckle filters preserve the polarimetric power and texture signatures of textured targets. To this aim, such signatures are quantitatively compared to their counterparts in the MAP filtered polarimetric data
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... follows: lM.'X*.Ci'.X-LRi -R~.Z[log(Rik)-l/Ln(lO)] = 0 ... issue. [13] F. Yakam-Simen, E. Nezry and J. Ewing, 1999: "The legendary lost city 'Ciudad Blanca' found in the Honduran tropical forest, using ERS-2... more
... follows: lM.'X*.Ci'.X-LRi -R~.Z[log(Rik)-l/Ln(lO)] = 0 ... issue. [13] F. Yakam-Simen, E. Nezry and J. Ewing, 1999: "The legendary lost city 'Ciudad Blanca' found in the Honduran tropical forest, using ERS-2 and JERS-1 SAR imagery", Proc. ...
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ABSTRACT Not Available
ABSTRACT
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ABSTRACT On January 13th 2001, a very strong earthquake struck El-Salvador, causing almost 1000 deaths and huge destruction, leaving more than one million people homeless. As support to the rescue teams, a project was initiated to provide... more
ABSTRACT On January 13th 2001, a very strong earthquake struck El-Salvador, causing almost 1000 deaths and huge destruction, leaving more than one million people homeless. As support to the rescue teams, a project was initiated to provide up-to date maps and to identify damages to housing and infrastructures, covering the whole country. Based on the analysis of SPOT Panchromatic satellite imagery, updated maps were delivered to the rescue teams within 72 hours after the earthquake. In addition, during the 10 days following the earthquake, high resolution mapping of the damages was carried out in cooperation and coordination with rescue teams and relief organizations. Some areas of particular interest were even processed and damage maps delivered through the Internet, three hours after the request. For the first time in the history of spaceborne Earth observation, identification and evaluation of the damages were delivered on-site, in real-time (during the interventions), to local authorities, rescue teams and humanitarian organizations. In this operation, operating 24 hours a day and technical ability were the keys for success and contributed to saving lives.
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ABSTRACT Five new Distribution-Energy Maximum A Posteriori speckle filters are established for the following cases: single detected, multilook multi-channel detected, single look complex SAR images, separate complex looks, and fully... more
ABSTRACT Five new Distribution-Energy Maximum A Posteriori speckle filters are established for the following cases: single detected, multilook multi-channel detected, single look complex SAR images, separate complex looks, and fully polarimetric SAR data. As shown, these new filters are particularly efficient to reduce speckle noise, while preserving textural properties and spatial resolution, especially in strongly textured SAR images.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
ABSTRACT
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As the output of the SAR data processor is a complex number, speckle reduction should take profit of the additional information contained in the phase and in the complex correlation between the different images. In order to obtain high... more
As the output of the SAR data processor is a complex number, speckle reduction should take profit of the additional information contained in the phase and in the complex correlation between the different images. In order to obtain high equivalent number of looks, we develop the Complex Gaussian-Gamma MAP (Maximum A Posteriori) fdter for complex multiplicative speckle noise and for
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In many SAR image processing stages such as speckle filtering, image segmentation and simulation, it is useful to know the theoretical properties of the image. The a priori knowledge can then be incorporated in the processing for a better... more
In many SAR image processing stages such as speckle filtering, image segmentation and simulation, it is useful to know the theoretical properties of the image. The a priori knowledge can then be incorporated in the processing for a better performance. These properties are often the first order statistics (the probability density function i.e. the pdf) for the underlying scene and
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Two new Bayesian vector speckle filters have been developed for multi-channel SAR images. Since these filters present the structure of data fusion control systems, their application is the first processing step of application-oriented... more
Two new Bayesian vector speckle filters have been developed for multi-channel SAR images. Since these filters present the structure of data fusion control systems, their application is the first processing step of application-oriented control systems designed to exploit the synergy of SAR sensors. The authors present such a control system, to retrieve soil roughness and soil moisture using ERS and
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The states of Honduras, Nicaragua, and El Salvador have been toughly hit by the "Mitch" hurricane in the first days of November 1998. The extent of damages due to this hurricane, as well as their impact upon local economy were... more
The states of Honduras, Nicaragua, and El Salvador have been toughly hit by the "Mitch" hurricane in the first days of November 1998. The extent of damages due to this hurricane, as well as their impact upon local economy were exceptional. In this framework, a remote sensing project was scrambled to provide a large scale evaluation of the damages suffered by the three countries. To reach this objective, new remote sensing products called DYNAMIC products have been designed. These products are, based on using, either RADAR satellite images, or Optical/RADAR satellite data fusion. The most efficient techniques have been applied to produce these products, thus enabling change detection at a very fine spatial scale (10x10 meters). Project schedule and operations, as well as the validation of its products are reported in this paper.
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Privateers NV generated a DEM from optical LANDSAT TM and Spot images as first layer for the GIS system that is used in the Hustain Nuruu national park in Mongolia by the re- introduction program of the Przewalski horse.
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On January 13th 2001, a very strong earthquake stroke El-Salvador, causing almost 1000 deaths and huge destruction, leaving more than one million people homeless. In support to the rescue teams, a project was put up to provide up-to date... more
On January 13th 2001, a very strong earthquake stroke El-Salvador, causing almost 1000 deaths and huge destruction, leaving more than one million people homeless. In support to the rescue teams, a project was put up to provide up-to date maps and to identify damages to housing and infrastructures, covering the whole country. Based on the analysis of SPOT Panchromatic satellite imagery, updated maps were delivered to the rescue teams within 72 hours after the earthquake. In addition, during the 10 days following the earthquake, high resolution mapping of the damages was carried out in cooperation and coordination with rescue teams and relief organizations. Some areas of particular interest were even processed and damage maps delivered through the Internet 3 hours after request. For the first time in the history of spaceborne Earth observation, identification and evaluation of the damages have been delivered on-site, in real-time (during the interventions), to local authorities, rescu...