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Geoscience and Remote Sensing Symposium, 1999. IGARSS '99 Proceedings. IEEE 1999 International

Date June 28 1999-July 2 1999

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  • IGARSS'99 Proceedings [front matter]

    Publication Year: 1999 , Page(s): i - xci
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  • Author index

    Publication Year: 1999 , Page(s): 2771 - 2782
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  • Monitoring the evolution of Europe's urban landscapes

    Publication Year: 1999 , Page(s): 2705 - 2707 vol.5
    Cited by:  Papers (1)
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    Monitoring urban dynamics (MURBANDY) aims to provide a synoptic view of Europe's urban areas and their dynamics using very high resolution satellite imagery. MURBANDY also measures past land uses and combines them with a socio-economic data-set to understand historical development of cities and develops scenarios of urban growth. Preliminary results show that most cities have more than doubled in size in the last 50 years View full abstract»

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  • Evaluation and comparison of two fuzzy classifiers for multi-spectral imagery analysis

    Publication Year: 1999 , Page(s): 2495 - 2497 vol.5
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    Two fuzzy classifiers were evaluated and compared in this study. A parameter, fuzzy classification accuracy, was proposed in order to evaluate the two classifiers. The experimental results indicate that the two fuzzy classifiers are potential algorithms for classifying mixed pixels in multispectral images, and the neural network classifier trained with the data containing mixed pixels performed better in classification quality for mixed pixels, compared to the posterior probability classifier and the neural network classifier trained with the data containing converted pure pixels from mixed pixels View full abstract»

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  • POLSAR data compensation for terrain azimuth slope variation

    Publication Year: 1999 , Page(s): 2437 - 2439 vol.5
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    This paper addresses the problem of polarimetric SAR data correction for slope induced radar cross section variations in the azimuth direction. Most radiometric slope corrections remove slope effects in the range direction to account for local incidence angle variation. Two approaches to compensate azimuth slope effects are proposed. In the first approach, the DEM, obtained from interferometric SAR or other means is used to estimate the orientation angle, and in the second approach, the orientation angle is derived from Cloude's and Huynen's decompositions, and the peak-shift in polarization signature. Comparison on the accuracy of estimating the orientation angle with that derived from the DEM is given. NASA/JPL AIRSAR data is used for illustration View full abstract»

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  • Data compression-a possibility for the integration of remote sensing data in GISs

    Publication Year: 1999 , Page(s): 2687 - 2689 vol.5
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    One main goal of processing remote sensing data is the classification of these data to derive thematic maps and to include those in geographical information systems (GIS). In this study the authors focus on RADAR-data. The classification of RADAR-data shows various advantages and disadvantages compared with a classification based on optical data. Main advantages are the independence of atmospheric conditions, the independence of illumination and the penetration depth, which allows an observation of volumetric properties and surface properties. A detailed explanation of the advantages is given elsewhere. Disadvantages arise from the special geometry of RADAR-systems (forshortening, layover) and the ambiguity of the signal interference patterns (speckle). Speckle filters are implemented in various image processing software packages, but an improvement of speckle reduction techniques is necessary to allow an automatic classification. Taking into account that speckle can be regarded as a stochastic process and not as information, it is obvious to treat the processes of data compression and speckle removal as one problem. Therefore the author gives an overview on compression techniques and the coding scheme used in chapter 2. Chapter 3 describes the integration of algorithms in a commercial GIS/remote sensing package. In the final chapter 4 a glance on applications is made View full abstract»

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  • Active and passive microwave multi-sensor system for anti-personal mine detection

    Publication Year: 1999 , Page(s): 2461 - 2464 vol.5
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    The major problems of the presently available mine detection equipment are its reliability, the safety of the operators, and the efficiency limited by the very high number of false alarms. Consequently, the principal goals of the authors' project supported by the European Community for a modern, reliable, efficient and handheld mine detection system must be focused on the following key requirements: The system should be capable of detecting small surface and subsurface plastic mines with very low metal content under most environmental conditions; the detection probability should be maximised; the hardware expense should be as most cost-effective as possible. Following previous investigations the authors believe that these very complex tasks can be fulfilled by a multi-sensor system consisting of a metal detector, a ground penetrating radar, and a microwave radiometer. This paper considers only the microwave part of the system View full abstract»

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  • Radio-wave penetration in the Greenland Ice Sheet inferred from interferometric correlation

    Publication Year: 1999 , Page(s): 2383 - 2385 vol.5
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    A novel way to exploit radar interferometry for studying glacier structure is to use interferometric correlation. Spatial decorrelation, a function of viewing angle difference between observations, is exacerbated by volume scatter; the larger the vertical extent of the scatterers contributing to the radar echo, the greater the decorrelation. By modelling this effect and accounting for other types of correlation the authors can determine radio wave penetration depths. They have done this for an area within the dry snow zone of Greenland using ERS data, and have found a mean C-band penetration depth of ~33 m View full abstract»

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  • Acquisition and updating of ATKIS using satellite remote sensing imagery

    Publication Year: 1999 , Page(s): 2690 - 2692 vol.5
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    Remote sensing is one of the workhorses of topographic and thematic mapping of large areas of the Earth surface and is a prime data source for the acquisition and updating of topographic geo-data at small scales. Satellite imagery of a sub-meter ground resolution in the panchromatic channel, which has been announced for some time and will most probably be available in the near future, has the potential to be also useful in medium scale applications. Along with the better resolution a change of automatic image exploitation techniques from purely pixel-based multi-spectral classification to model-based image analysis, and an increasing integration with GIS (geographic information system) can be observed View full abstract»

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  • Multiresolution techniques in microwave tomography and subsurface sensing

    Publication Year: 1999 , Page(s): 2516 - 2518 vol.5
    Cited by:  Papers (2)
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    The application of multiresolution techniques to subsurface sensing in the framework of linearized models of the scattering equation and in 2D geometry is considered. In particular, two approaches based on the so called “fixed” and “adaptive” multiresolution schemes, are been proposed View full abstract»

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  • Multi-resolution phase model reconstruction for phase unwrapping

    Publication Year: 1999 , Page(s): 2395 - 2397 vol.5
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    An algorithm for phase unwrapping is presented that deals with the problem of error propagation due to interferometric noise. The proposed technique belongs to the category of global analysis methods, and it is based on the generation of an approximate phase model, which is iteratively refined until a stopping condition is reached. The underlying principle is that the interferogram is partitioned into square-shaped, non-overlapping elements such that the unwrapped phase on each element can be modelled by the mean value of the local slopes. Starting from this information, which in two dimensions is represented by flat surfaces that best fit the real ground behaviour, the global model is reconstructed by linking the vertices of the found planes through the solution of a least mean square problem. The effectiveness of this method is limited by the presence, in real interferometrical data, of large areas in which the information about local slopes is absent due to layover, noise, vegetation, etc. In order to solve this problem, a weighted version of the algorithm has been developed View full abstract»

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  • Corner reflectors' responses observed by X-band polarimetric airborne synthetic aperture radar

    Publication Year: 1999 , Page(s): 2667 - 2669 vol.5
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    In order to make radiometric calibration of an X-band airborne synthetic aperture radar (SAR), calibration targets of trihedral corner reflectors (consisting of four different sizes) were imaged several times. The radar was developed by the Communications Research Laboratory (CRL) for research purposes and has been operated, with polarimetric and interferometric functions, simultaneously with an L-band SAR developed by the National Space Development Agency of Japan (NASDA). The authors show some results of the calibration experiments with the reflectors deployed in a dune in 1998 focusing on radiometric calibration of like-polarization (HH and VV) images. Also shown are results of a similar calibration experiment in a frozen lake in 1999, to verify calibration coefficients estimated from the previous experiment View full abstract»

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  • Towards operational systems of monitoring regional patterns of degradation in Sahelian Africa - a multisensor remote sensing approach

    Publication Year: 1999 , Page(s): 2563 - 2565 vol.5
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    Presents preliminary results of two case studies focussing on Sahelian regions of the Niger inland delta (Mali, West Africa). The focus is set on the important preprocessing step of data homogenization for supporting reasonable comparative investigations of multitemporal and multisensor Earth observation data. The first study deals with the preprocessing of radiometric and atmospheric corrections applied to a series of LANDSAT-MSS data from the dry season of 1972, 1974 and 1982, covering the region of Lac Faguibine, at the northern fringe of the Niger inland delta. The accurate assessment of landcover change depends on the correction of different sensor radiometry. The second study deals with computer assisted photo interpretation. Image analysis of rasterized photographic data has some positive drawbacks compared with traditional visual photo interpretation. Results of detection and evaluation of quantitative indicators are more accurate and thus finer landcover change evaluation is made possible View full abstract»

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  • Calibration of the RADARSAT SWB processor at the Alaska SAR Facility

    Publication Year: 1999 , Page(s): 2355 - 2359 vol.5
    Cited by:  Papers (1)
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    Calibration of the RADARSAT ScanSAR Wide B (SWB) processor at the Alaska SAR Facility (ASF) was completed at the end of 1998, making ASF one of the world's first synthetic aperture radar (SAR) processing facilities to distribute calibrated ScanSAR data to its users. SWB is one of several imaging modes onboard Canada's RADARSAT C-band SAR satellite. In the SWB beam-mode, wide-swath coverage of 450 km is achieved by combining four overlapping beams each about 150 km in range. To meet the requirements for absolute radiometric calibration error of +/-2 dB and relative calibration error of +/-0.5 dB, the authors used external calibration data of the Amazon rain forest. Absolute location accuracy requirements (+/-500 m) were verified using corner reflectors and U.S. Department of Defense coastline data. Results show radiometric and geometric calibration for the ASF RADARSAT SWB processor meet specifications. Image quality issues such as scalloping and beam overlap regions are discussed, as are several software tools that allow users to more effectively utilize SWB data View full abstract»

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  • Analysis of the iterative Kirchhoff approximation for rough surface scattering

    Publication Year: 1999 , Page(s): 2410 - 2412 vol.5
    Cited by:  Papers (2)
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    The iterative Kirchhoff approximation has been numerically applied to one-dimensionally rough, perfectly conducting statistical surfaces, and the backscattering predicted from the first and second iterations compared with the “exact” scattering found from the moment method. The VV second-iteration scattering proves accurate at all incidence angles with slightly rough surfaces and up to 85° with large-scale rough surfaces. At HH the second-iteration scattering loses accuracy at 75° with small scale rough surfaces and 50° with large-scale roughness. Scattering models based on the second-iteration IKA actually give better results at HH than would be suggested by the numerical evaluation of the IKA. The numerical results show that these models can be accurately applied to surfaces that include moderate large-scale roughness without first separating the roughness spectrum into large- and small-scale components View full abstract»

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  • Monitoring urban areas by using ERS-SAR data and neural networks algorithms

    Publication Year: 1999 , Page(s): 2696 - 2698 vol.5
    Cited by:  Papers (1)
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    This contribution discusses the kind of information contained in multitemporal SAR data and shows how it can be exploited for classifying the urban area of Rome, Italy. Multitemporal, coherence and textural features are obtained from a set of SAR images taken in winter, spring and summer by the ERS tandem mission. These features are used to identify areas belonging to various urban classes, including water surfaces, woodland and parks, and continuous high/low density residential areas. The decision-making process is performed by a classifier based on a neural network algorithm View full abstract»

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  • Experimenting with radar backscattering models using E-SAR imagery

    Publication Year: 1999 , Page(s): 2628 - 2630 vol.5
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    This paper presents a study on the problem of separation and extraction of interrelated parameters, namely soil moisture and surface roughness, from a series of radar images acquired with the DLR airborne experimental sensor E-SAR. Many models have been developed in the active microwave domain to explain backscatter as a function of soil moisture and/or surface roughness. The complexity of the theoretical models and the non reliability of the empirical models motivated the authors to choose semi-empirical models. The results produced up to now using the OH-model show a rough compliance with the soil moisture terrain observations, but it has to be ameliorated significantly for the roughness estimation. The results obtained using the DUBOIS-model show a better agreement with C-band than with L-band. In this context, the relation between the estimated soil surface parameters (RMS-height and dielectric constant) and the relative and/or absolute sensor calibration errors were analysed. A review of the DUBOIS-model will also be described. It has been found that model parameter adaptions were necessary in the case of the authors hilly agricultural catchment area View full abstract»

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  • Three dimensional urban characterization by IFSAR measurements

    Publication Year: 1999 , Page(s): 2401 - 2403 vol.5
    Cited by:  Papers (5)
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    In this paper a machine vision approach is applied to IFSAR data to extract the most relevant built structures in a dense urban environment. The algorithm tries to cluster primitives (line segments) into more complex surfaces (planes) to approximate the 3D shape of these objects. Very interesting results starting from TOPSAR data recorded over S. Monica are presented View full abstract»

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  • Effects of surface currents on airborne cross track radar interferometry

    Publication Year: 1999 , Page(s): 2610 - 2612 vol.5
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    Since airborne cross track interferometry provided successful results in imaging land surfaces, a mission for achieving high resolution interferometric products over the Waddensea in the German Bight was carried out. In contrast to the nonflooded areas, the interferometric phase over water surfaces, such as tidal channels, was not as expected and indicated an additional interferometric phase difference. It could be induced by the surface movement under squinted imaging geometry, that leads to an along track component. Investigations show that there are some reasons that can add up to the authors' observation. Also experimental data proving this effect are shown View full abstract»

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  • On the use of the polarization information for ice storm tree damage assessment in the Ottawa region

    Publication Year: 1999 , Page(s): 2455 - 2457 vol.5
    Cited by:  Papers (1)
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    During January, 1998 an unusual and devastating series of ice storms occurred in eastern Ontario and western Quebec. Many forested areas in both these provinces were seriously damaged and sustained severe structural changes which ranged from loss of limbs to being bent horizontally to the ground. The impact on the forests varied from moderate to severe and was usually a function of tree type, and the local severity of the ice storms. In this paper, an investigation is made into the possibility of using the polarization information for classification of damaged forest areas. Polarimetric synthetic aperture radar (SAR) data were collected over a scene in the Ottawa region with the Department of the Environment Convair-580. Reference point targets were deployed during the flight, and used to calibrate the four measured linear polarizations (HH, VV, HV, and VH) in magnitude and phase. Ground truth data were collected in the field and from a helicopter flight View full abstract»

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  • The Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS): concept and performance

    Publication Year: 1999 , Page(s): 2674 - 2677 vol.5
    Cited by:  Papers (3)
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    Describes the key features and expected performance of a new radar sounder instrument currently under development by a team of Italian and US researchers and industrial partners, selected to fly with the ESA Mars Express orbiter scheduled for launch to Mars late in 2003. Very low transmitted frequency (1-5 MHz), large instantaneous bandwidth and coherent on-board processing techniques will make it possible to acquire a large amount of science-relevant data about the Mars interior, surface and atmosphere ensuring global coverage at all latitudes while respecting the Mars Express mission constraints View full abstract»

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  • Mapping the features of the chora of Chersonesos via remotely sensed data

    Publication Year: 1999 , Page(s): 2569 - 2571 vol.5
    Cited by:  Papers (1)
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    The chora of Chersonesos, located in southeast Crimea, Ukraine, is a uniquely well-preserved ancient agricultural territory in danger of destruction by urban encroachment and coastal erosion. This study investigates the use of remotely sensed data for the mapping of archaeological features in the territory and as a means to monitor urban encroachment and coastal erosion that threaten this historic monument. Historic aerial photography and Corona photography are being analyzed to map archeological features. A digital elevation model (DEM) created via repeat pass interferometry from the European Remote Sensing (ERS) satellite is being used in conjunction with the multispectral imagery and geophysical and geomorphological in situ data to study the ancient settlement of the area and identify and monitor vulnerable parts of the chora. Preliminary results from classification of Landsat multispectral data and comparisons of Corona photography and the Indian Remote Sensing (IRS) satellite panchromatic data indicate a massive increase in the urban land cover in the study area during the last few decades. A geographical information system (GIS), for which the remotely sensed data provides the spatial framework for integrating site specific and regional information, is being developed for the site as an aid in land use planning, site protection, and development of an archaeological park View full abstract»

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  • Ground penetrating impulse radar for detection of small and shallow-buried objects

    Publication Year: 1999 , Page(s): 2468 - 2470 vol.5
    Cited by:  Papers (10)  |  Patents (1)
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    The video impulse system ground penetrating radar system for detection of small and shallow buried objects has been developed. The hardware combines commercially available components with components (e.g. antennas) specially developed or modified for being used in the system. Antenna system has been designed so that it provides sufficient spatial resolution and power budget together with small coupling and ringing. The GPR has been tested in different environmental conditions and has proved its ability to detect small and shallow buried targets View full abstract»

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  • Tracking of fresh-water plumes in Dutch coastal waters by means of HF radar

    Publication Year: 1999 , Page(s): 2548 - 2550 vol.5
    Cited by:  Papers (1)
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    Progress in electronics and computer techniques allowed the design of a new high-frequency (HF) radar system at the University of Hamburg (Germany). WERA (Wellen Radar) is a frequency-modulated continuous-wave (FMCW) radar which, when linked to a linear array of receive antennae, simultaneously measures surface currents and ocean waves. Operating at 27 MHz, the highest spatial resolution is 0.3 km. The area covered in this mode is about 40 km×40 km. Results from an experiment at the Dutch coast in boreal fall 1996 are presented. Occasionally, a high-velocity jet has been observed which travels northwards along the coast. At the edge of the jet, some 15 km to 30 km off the coast, the high-resolution mode of WERA revealed current shears of up to 0.002 s -1. It is assumed that the jet carries fresh water plumes which originate from the Rhine and Ijssel outflow into the North Sea. In addition to the surface currents, the spatial distribution of backscatter strength is investigated. Some evidence is found that, during phases of low wind, fresh water plumes become visible as areas of reduced backscatter. This finding is in accordance with the dependence of HF ground-wave attenuation on sea-water conductivity View full abstract»

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  • Multi-scale indices for content-based image retrieval

    Publication Year: 1999 , Page(s): 2377 - 2379 vol.5
    Cited by:  Papers (3)
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    For automatic remote-sensing image interpretation it is important to give specific consideration to the resolution of the data. The performance of content-based retrieval systems can be enhanced significantly if the scale of spatial features is used explicitly as a meta feature. This allows to use low-dimensional feature vectors at each scale instead of a high-dimensional feature vector for all scales. The authors developed a system where the user can query for signal properties, like texture characteristics. He is encouraged to restrict the search space by indicating the scale he is interested in. The signal oriented search is done using indices that are computed completely unsupervised. These indices represent the characteristic signal classes of the data. The system does no interpretation of the classes. It is up to the user to “name” the contents according to his application interest View full abstract»

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