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Geoscience and Remote Sensing Symposium, 1994. IGARSS '94. Surface and Atmospheric Remote Sensing: Technologies, Data Analysis and Interpretation., International

Date 8-12 Aug 1994

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Displaying Results 1 - 25 of 197
  • The generation and propagation of internal wave forms in the Strait of Gibraltar studied by ERS-1 SAR imagery and a numerical model

    Publication Year: 1994, Page(s):2023 - 2025 vol.4
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    The generation and propagation of internal waves in the Strait of Gibraltar has been studied by analyzing 131 ERS-1 SAR scenes from 78 satellite overflights over this area in the period from December 1991 to February 1994. From the analysis of the ERS-1 SAR images the authors obtain the following results: (1) roughness patterns over the Camarinal Sill are visible from 1h after low tide at Gibralta... View full abstract»

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  • ERS-1 SAR images of atmospheric gravity waves

    Publication Year: 1994, Page(s):2026 - 2028 vol.4
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    ERS-1 synthetic aperture radar (SAR) images of atmospheric gravity waves are discussed. One case study is presented in detail, in which it is shown that the intense long wavelength phenomenon observed in the SAR image is an atmospheric gravity wave generated by the passage of a warm front. Atmospheric soundings and a 2-layer model indicate that the wave phenomenon could have been supported by the ... View full abstract»

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  • Design of a Ka band polarimetric radiometer

    Publication Year: 1994, Page(s):2419 - 2420 vol.4
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (164 KB)

    In order to develop the capability of conducting more efficient research flights, the University of Massachusetts secured funding from the U.S. Navy to develop a Ka band polarimetric radiometer for future airborne surveys. The design, which is discussed, uses concepts developed as part of the ESTAR thinned array radiometer project, which uses correlation techniques to image terrain at L... View full abstract»

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  • Motion compensation for airborne SAR based on inertial data, RDM and GPS

    Publication Year: 1994, Page(s):1971 - 1973 vol.4
    Cited by:  Papers (12)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (228 KB)

    Two new motion compensation methods for airborne SAR are presented. Both methods are based on the evaluation of acceleration data measured by an Attitude and Heading Reference System (AHRS). The motion compensation algorithms were developed for the Experimental SAR System (E-SAR) of DLR which operates in L/C/X-Band. It is installed in a small Dornier Do-228 turboprop aircraft. Due to atmospheric t... View full abstract»

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  • Model-based feature classification and change detection

    Publication Year: 1994, Page(s):2531 - 2533 vol.4
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    Describes a novel image processing system which performs constant false-alarm rate (CFAR) change detection and model-based feature classification on temporally separated and precision registered images. The authors present results of algorithms performed on 0.5 m to 2 m resolution scanned aerial photographs of the Yuma, Arizona region to identify changes that correspond to man-made targets and new... View full abstract»

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  • Multispectral classification by a modular neural network architecture

    Publication Year: 1994, Page(s):1873 - 1876 vol.4
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (264 KB)

    Deals with the application of a modular neural network system to classification of remote sensed data characterized by a high number of spectral bands. The classification task was separated into two phases: (i) unsupervised data compression by a linear propagation network (LPN); (ii) supervised feature classification by a multi layer perceptron (MLP). In this work the unsupervised LPN module has b... View full abstract»

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  • Transmitted radiation of searchlight in turbid atmosphere

    Publication Year: 1994, Page(s):1911 - 1913 vol.4
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    It is shown how to get an analytically Cauchy system of the scattering and transmission functions in the searchlight problem in a turbid atmosphere bounded by a diffuse reflector. An invariant imbedding leads to an initial-value solution of the scattering and transmission functions for the searchlight. The Riccati-type of nonlinear integro-differential equations are used. The authors discuss the c... View full abstract»

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  • MTF measurement using spotlight

    Publication Year: 1994, Page(s):2010 - 2012 vol.4
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB)

    For Earth observation satellites such as SPOT, it is important to measure the modulation transfer function (MTF) in order to quantify the spatial resolution of the imaging system. This measurement is useful to decide to focus the telescope or to make a deconvolution filter whose purpose is to enhance image contrast by ground processing. The paper presents an MTF measurement method used during the ... View full abstract»

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  • Interpretation of parametric maps obtained by means of “blue to green ratio” over coastal waters

    Publication Year: 1994, Page(s):2106 - 2108 vol.4
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    This paper deals with the effects of dissolved organic matter on the “blue to green ratio” used for pigment estimation in oceanography. A model of ocean colour by Sathyendranath et al. (1989), with slight modifications, was used to compute mean reflectance values in the blue and green channels of a radiometer. A statistical analysis was performed to find the best correlation between th... View full abstract»

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  • Aerosol retrieval based on photopolarimetry

    Publication Year: 1994, Page(s):1898 - 1900 vol.4
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (128 KB)

    Photopolarimetric measurements of atmospheric aerosols are interpreted based on an idea that aerosol characteristics can be estimated in terms of the scattering behavior. The radiance and polarization degree of atmospheric aerosols were measured by using the portable photopolarimeter (FPR2000) at wavelengths 0.559, 0.662 and 0.811 μm, which correspond to the wavelengths of the optical sensor (O... View full abstract»

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  • Discrimination between young sea ice types from single look SAR image texture

    Publication Year: 1994, Page(s):2158 - 2161 vol.4
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (408 KB)

    This study addresses the modeling of synthetic aperture radar (SAR) image texture for sea ice targets in the Labrador marginal ice zone (MIZ). The image texture of distributed scatterers contains a substantial component relating to the imaging system as well as information about the target itself. Theory shows that the image autocorrelation function (ACF) may be analyzed to separate system contrib... View full abstract»

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  • A new MTI-SAR-approach using the reflectivity displacement method

    Publication Year: 1994, Page(s):1974 - 1976 vol.4
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (300 KB)

    The detection of moving targets by a side-looking air- or space-borne synthetic aperture radar (SAR) is limited due to the bandwidth of the clutter. It has an azimuth spectrum whose bandwidth is determined by the antenna beamwidth in azimuth, the platform speed and the wavelength. Application of the reflectivity displacement method (RDM) allows the detection of moving targets, whose azimuth spectr... View full abstract»

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  • On-line complex permittivity measurements for ground penetrating radar

    Publication Year: 1994, Page(s):2513 - 2515 vol.4
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (188 KB)

    One of the major problems for a subsurface radar to predict is the true target distance and maximum likely penetration depth in the media under investigation. These radar parameters can be determined from the complex permittivity of the media. Since the permittivity of the surface under examination is usually unknown, most subsurface radars are calibrated in time units only: actual subsurface dist... View full abstract»

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  • Estimation of penetration depth in a random medium using frequency decorrelation of the backscattered field

    Publication Year: 1994, Page(s):2492 - 2493 vol.4
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (140 KB)

    Frequency decorrelation of co-polarized and cross-polarized fields backscattered from a random medium is shown to be sensitive to the penetration depth and the physical parameters of the medium. The backscatter decorrelation bandwidth is shown to be inversely proportional to the penetration depth. Measurements conducted on snow under wet and dry conditions using 35 and 94 GHz scatterometers showed... View full abstract»

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  • Modeling surface effects with the parabolic equation method

    Publication Year: 1994, Page(s):2322 - 2325 vol.4
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB)

    An approximate but efficient technique is presented that accounts for vertical polarization and rough surface effects over the sea for ducting conditions using the split-step parabolic equation method. The primary justification for this semi-empirical technique is that in most cases propagation loss predictions match results from a waveguide model that is believed to account for these effects prop... View full abstract»

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  • Design of new photodiode standards for use in the MISR in-flight calibrator

    Publication Year: 1994, Page(s):1998 - 2000 vol.4
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    The Multi-Angle Imaging SpectroRadiometer (MISR) is to be launched in 1998 as part of NASA's Earth Observing System. The 3% (1σ) absolute radiometric calibration requirement for this instrument is considered challenging, particularly since it must be maintained through the five-year mission life. To meet this specification MISR will rely on detector-based calibration techniques, which are pr... View full abstract»

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  • Spectral error characterization and database development

    Publication Year: 1994, Page(s):2534 - 2537 vol.4
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    The authors are utilizing existing data as well as additional materials characterization to provide high resolution spectra and error statistics for a wide range of engineered and natural materials. Important aspects of the authors' methodology involve determining the variability of these measurements between samples and among different samples belonging to broad material classes (e.g., soils, roc... View full abstract»

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  • PRF ambiguity determination for Radarsat ScanSAR system

    Publication Year: 1994, Page(s):1964 - 1966 vol.4
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (236 KB)

    PRF ambiguity is a potential problem for a spaceborne SAR operated at high frequencies. For a strip mode SAR, there were several approaches to solve this problem. This paper, however, addresses PRF ambiguity determination algorithms suitable for a burst mode SAR system such as the Radarsat ScanSAR. The candidate algorithms include the wavelength diversity algorithm, range look cross correlation al... View full abstract»

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  • Restoration of textural properties in SAR images using second order statistics

    Publication Year: 1994, Page(s):2165 - 2167 vol.4
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (504 KB)

    Local second order properties, which describe spatial relations between pixels are introduced into single-point speckle filtering processes, in order to account for the effects of speckle correlation and to enhance scene textural properties in the restored image. To this end, texture measures originating, first from local grey level co-occurrence matrices (GLCM), then from the local autocorrelatio... View full abstract»

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  • A combination of temporal thresholding and neural network methods for classifying multiscale remotely-sensed image data

    Publication Year: 1994, Page(s):1877 - 1879 vol.4
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    A thresholding technique applied to a time series of 1 km, biweekly composited AVHRR-NDVI data stratifies a Sierra Nevada test site into broad vegetation classes based on temporal habit. These classes provide a basis for developing strata specific neural network classifiers which operate on single date 250 m and 500 m data simulated from Landsat Thematic Mapper, as well as 1000 m digital elevation... View full abstract»

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  • Measurements of ocean currents with SAR interferometry and HF radar

    Publication Year: 1994, Page(s):2020 - 2022 vol.4
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (268 KB)

    The purpose of this paper is to report the authors' preliminary efforts to calibrate and intercompare interferometric SAR and OSCR HF radar measurements of ocean current fields collected during the ONR High-Resolution Remote Sensing Experiment in June, 1993. This experiment acquired both strip-map and interferometric SAR imagery from a region that contained interesting oceanographic features where... View full abstract»

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  • Simulation of SAR images of submesoscale ocean phenomena

    Publication Year: 1994, Page(s):2015 - 2016 vol.4
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (152 KB)

    Patterns are observed on radar images of the ocean surface on scales of 10-1000 meters which are related to phenomena such as internal waves, current or temperature fronts, and tidal flow over shallow bottom topography. These features are caused by a complex set of interactions between surface waves, air flow above the surface, current fields at and below the surface, and the electromagnetic waves... View full abstract»

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  • Monitoring land surfaces with combined DMSP-SSM/I and ERS-1 scatterometer data

    Publication Year: 1994, Page(s):1945 - 1947 vol.4
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB)

    Microwave data from the DMSP-SSM/I sensor and the ERS-1 Scatterometer are used to monitor the temporal behaviour of deserts, forests and snow-covered areas. The SSM/I brightness temperatures were spatially interpolated using the algorithm proposed by Poe (1990). In order to detect the different land surface types according to their spectral signature, the surface emissivity has to be derived from ... View full abstract»

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  • Multispectral LANDSAT images segmentation using neural networks and multi-experts approach

    Publication Year: 1994, Page(s):2109 - 2111 vol.4
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (228 KB)

    The application of a combined segmentation method using the Canny-Deriche filter and a multi layer perceptron neural network is considered. The segmentation of five LANDSAT spectral bands is conducted. Obtained segmented images are combined using a multi experts approach in order to improve the segmentation quality and to preserve the land cover regions View full abstract»

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  • 93 GHz airborne imaging radiometer

    Publication Year: 1994, Page(s):2243 - 2245 vol.4
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    A 93 GHz conically scanning imaging radiometer is under construction at HUT. The system consists of a sensor unit to be mounted under a Bell Jetranger helicopter and a control electronics unit to be strapped on the helicopter's back seat. The new features of the compact instrument are the ability to follow any conical scan path, the airborne liquid nitrogen cooled cold calibration as well as the f... View full abstract»

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