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Geoscience and Remote Sensing, IEEE Transactions on

Issue 5 • Date Sept. 1989

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Displaying Results 1 - 20 of 20
  • Multiple incidence angle SIR-B forest observations

    Publication Year: 1989 , Page(s): 586 - 591
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (625 KB)  

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  • Estimation of signal-to-noise: a new procedure applied to AVIRIS data

    Publication Year: 1989 , Page(s): 620 - 628
    Cited by:  Papers (28)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1496 KB)  

    To make the best use of narrowband Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data, an investigator needs to know the signal-to-noise ratio (SNR). The signal is land cover dependent and varies with both wavelength and atmospheric absorption, and random noise comprises sensor noise and intrapixel variability (i.e. variability within a pixel). The three existing methods for estimating the SNR are inadequate, since typical laboratory methods inflate, while typical dark-current and image methods deflate the SNR value. The authors propose a procedure called the geostatistical method that is based on the removal of periodic noise by notch filtering in the frequency domain and the isolation of sensor noise and intrapixel variability using the semivariogram. This procedure was applied easily and successfully to five sets of AVIRIS data from the 1987 flying season and could be applied to remotely sensed data from broadband sensors View full abstract»

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  • Snow cover detected by diurnal warming of sea ice/snow surface off Labrador in NOAA imagery

    Publication Year: 1989 , Page(s): 552 - 560
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1512 KB)  

    Four consecutive NOAA-9 infrared images show diurnal warming of the sea-ice surface off the coast of Labrador. For three subdomains with scales of ~100 km, the warming of the surface is obtained on the assumption that the warming of the surface is obtained on the assumption that the warming in one pixel is proportional to ice compactness, which is given in turn by brightness of a visible (daytime) image. A one-dimensional heat transfer equation for snow and ice is solved. An algorithm to estimate the snow thickness, which is required to calculate the heat flux through ice, from this extra warming is proposed View full abstract»

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  • Constraint optimum well-log signal segmentation

    Publication Year: 1989 , Page(s): 633 - 641
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (884 KB)  

    A special classification algorithm is proposed that can be applied to a preprocessed (or the original noisy) well-log signal for segmentation. Knowledge of the number of segments or any other constraint, if existent, along with a criterion function can be used to complete the algorithm. The preprocessing routine consists of a running window change-detection algorithm which detects all the potential candidates for the location of changes in the signal. This routing can be applied in way that significantly overestimates the number of changes. These points of change along with other estimated parameters are used by the classification algorithm to find the global best-segmentation that agrees with the a priori knowledge of the number of segments (or any other constraint) and satisfies a criterion function. The resultant optimum classification algorithm is recursive and computationally efficient. The performance of the overall algorithm is demonstrated by several examples View full abstract»

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  • Imaging of ocean waves by synthetic aperture radar: a comparison of results from Seasat and SIR-B experiments in the North Atlantic

    Publication Year: 1989 , Page(s): 568 - 575
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (864 KB)  

    New analyses of wave spectra extracted from Seasat SAR images of the JASIN site in the northeast Atlantic are presented as tests of wave-imaging theory. Spectra extracted from orbit 757 during a high sea state are dominated by the effects of smearing, but the rms image smear is less than half that expected from in situ measurements of surface motions. In a low sea state on orbit 547 fair agreement can be achieved between SAR and buoy spectra, but this requires that the smearing length be greater than was observed on orbit 757. These findings are compared with results obtained from the Shuttle Imaging Radar SIR-B mission in order to assess the quantitative understanding of wave imaging by SAR View full abstract»

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  • Estimating aircraft SAR response characteristics and ocean wave spectra in the Labrador Sea Extreme waves Experiment

    Publication Year: 1989 , Page(s): 483 - 491
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1508 KB)  

    The Labrador Extreme Waves Experiment (LEWEX) was an international effort to assess methods of measuring and modeling the directional aspects of wind-generated ocean waves, especially their evolution in the presence of rapidly turning winds. The author describes data-processing methods that have been developed to derive estimates of two-dimensional wave height-variance spectra from the ocean imagery obtained in LEWEX by a C-band synthetic aperture radar (SAR) system aboard a Canadian CV-580 aircraft. SAR spectra at altitudes of 20000 and 12000 ft are compared for both large (~50°) and small (~25°) radar look angles. Independence spectral estimates from both a surface contour radar and a radar ocean wave spectrometer aboard a NASA aircraft are used to verify the surface wave spectrum View full abstract»

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  • A review of sea ice and ocean modeling relevant to the Labrador and Newfoundland shelves

    Publication Year: 1989
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (664 KB)  

    Numerical and analytical models of sea ice and ocean circulation are reviewed from a viewpoint of their application to the Labrador and Newfoundland shelves. Seasonal variabilities of sea ice and ocean circulation have not been reported in numerical models. The difficulty comes from the importance of both stratification and bottom topography. Sea ice should be included for seasonal cycle calculations. Individual mechanisms of variabilities with time scales ranging from a day to a month have been studied extensively using various models so that the coupling of these models will make it possible to test the predictability of sea ice and ocean circulation. The data collected during LIMEX'87 and '89 provide verification of the models View full abstract»

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  • Rain, radiometry, and radar

    Publication Year: 1989 , Page(s): 576 - 585
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1012 KB)  

    A remote sensing system is proposed for quantitative operational measurement of the amount of liquid per unit volume in heavy rain. In particular, a 6-GHz radiometer in conjunction with a 10-cm wavelength radar is discussed. An experimental example involving a discrete heavy rain cell with a derived rainrate of 150 mm/h measured by a 6-GHz radiometer/3-GHz radar combination is given. The effect of clear air brightness temperatures, from oxygen and water vapor, on the 6-GHz radiometric rain measurements is analyzed, and an equation relating the 6-GHz brightness temperature from the rain to the radar backscattered power is derived. Design factors important in an operational observing system are also discussed View full abstract»

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  • Registering Landsat images by point matching

    Publication Year: 1989 , Page(s): 642 - 651
    Cited by:  Papers (61)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2236 KB)  

    Image registration of Landsat Thematic Mapper scenes with translational and rotational differences is studied. Two major steps of image registration, control-point selection and control-point matching, are emphasized. In control-point selection, the properties that a good control point should satisfy are defined. Several potential control-point candidates are suggested, and methods are discussed for extracting them from the input image. In control-point matching, a relaxation algorithm proposed in the literature is improved by reducing its time complexity from O(n4) to O(n3 ), where n is the number of control points. The matching algorithm also uses a two-way matching concept which utilizes the inherent symmetry property of the point-matching problem. The robustness of the proposed algorithm was demonstrated through simulation experiments by evaluating a matching index. Experimental results on Landsat images show that the proposed method produces results comparable to those obtained by an experienced photointerpreter View full abstract»

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  • Overview of LIMEX'87 ice observations

    Publication Year: 1989 , Page(s): 468 - 482
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3404 KB)  

    Ice observations, results, and conclusions are summarized for the March 1987 Labrador Ice Margin Experiment (LIMEX'87), an international oceanographic study conducted in the pack ice of the Grand Banks area off the coast of Newfoundland. Included are the ice extent, flow size and thickness, ice kinematics and rheology, ice microwave properties, oceanic properties under the ice, and penetration of swell into the ice View full abstract»

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  • Classification of radar signatures by autoregressive model fitting and cluster analysis

    Publication Year: 1989 , Page(s): 606 - 610
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (628 KB)  

    Ninety radar signatures were digitally recorded during the probing of ten different land and marine objects with a pulsed coherent Doppler radar. Their spectra were evaluated on the basis of the Marple algorithm for autoregressive model fitting. An attempt at classification is made. The method consists in representing the radar signatures as points in four-dimensional space and identifying the obtained clusters of four-dimensional points with the observed objects. The cluster analysis is carried out assuming that the classification parameters have different clustering lengths View full abstract»

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  • Seasat over-land scatterometer data. I. Global overview of the Ku-band backscatterer coefficients

    Publication Year: 1989 , Page(s): 592 - 605
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1944 KB)  

    Statistics on the backscatter coefficient σ0 from the Ku-band Seasat-A Satellite Scatterometer (SASS) collected over the world's land surfaces are presented. This spaceborne scatterometer provided data on σ0 between latitude 80° S and 80° N at incidence angles up to 70°. The global statistics of vertical (V) and horizontal (H) polarization backscatter coefficients for 10° bands in latitude are presented for incidence angles between 20° and 70° and compared with the Skylab and ground spectrometer results. Global images of the time-averaged V polarization σ0 at a 45° incidence angle and its dependence on the incidence angle are presented and compared to a generalized map of the terrain type. Global images of the differences between the V an H polarization backscatter coefficients are presented and discussed. The most inhomogeneous region, which contains the deserts of North Africa and the Arabian Peninsula, is studied in greater detail and compared with the terrain type View full abstract»

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  • An efficient technique for lithology classification

    Publication Year: 1989 , Page(s): 629 - 632
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (420 KB)  

    An efficient technique for the computer classification of lithologies is presented that utilizes well logs. For this study, a training data set has been obtained from a key well in the Abu-Garadig field area in the Western Desert of Egypt. The true classification of the training data is determined from the core description of the key well. Suboptimal feature selection techniques are used for the selection of the effective features containing most of the discriminatory information from a given set of measurements. The nearest-neighbor rule is used for classification after the editing and condensing of the training set in feature space. The classification rate, using all training patterns, is slightly higher than the rate obtained by using instead the condensed training set. The lithology classifier is used in other wells in the same field. The resulting classification rate demonstrates that the output lithologies are in accordance with geological reference View full abstract»

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  • Airborne SAR observations of ocean surface waves penetrating floating ice

    Publication Year: 1989 , Page(s): 492 - 500
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1144 KB)  

    The results are presented for a new and improved procedure for estimating the synthetic-aperture radar (SAR) image spectrum of ocean waves. This procedure, the spectral-sum method, involves summing individual image spectra derived from each of the looks of a multilook set. An automatic registration of the per-look spectral information is achieved, accounting for subimage look misregistration due to the wave propagation between looks. Spectral-sum processing is compared with traditional look-sum processing as a function of the radar slant-range. Spectral-sum processing is applied to SAR imagery of waves penetrating the marginal ice zone View full abstract»

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  • The effect of ice pressure on marginal ice zone dynamics

    Publication Year: 1989 , Page(s): 514 - 521
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (864 KB)  

    To evaluate the role of compressive ice pressure in marginal ice zone dynamics, a cavitating fluid model with periodic boundaries is developed and subjected to a fixed wind field and both cyclonic and anticyclonic wind vortices. In this model, ice interaction is approximated by assuming that sea ice has no resistance to divergence or shear, but has some compressive strength which is taken to be a linear function of compactness. Time scales of ice pressure effects are examined and their relevance to ocean eddies is discussed View full abstract»

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  • LIMEX '87 ice surface characteristics: implications for C-band SAR backscatter signatures

    Publication Year: 1989 , Page(s): 501 - 513
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1680 KB)  

    Ice surface characterization data collected in 1987, during the Labrador Ice Margin Experiment, are analyzed to estimate the changes in snow and ice properties at the onset of melt. Surface measurements were made from an ice research vessel on several days (some of which had coincident remote sensing flights) at a number of locations in the marginal ice zone. These data are used as input parameters in a simple scattering model to simulate the effects of variations in material properties upon C-band scattering signatures View full abstract»

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  • An improved decorrelation method for the efficient display of multispectral data

    Publication Year: 1989 , Page(s): 611 - 619
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1464 KB)  

    A technique to enhance multispectral image displays and to improve their visual interpretations is proposed. The decorrelation approach is tested with a SPOT simulation and thematic mapper image. The technique is considered to be of great help for the interpretation of remotely sensed images. Furthermore, the choice between two-, three-, and N -dimensional decorrelation allows the user to adjust to specific cases. However, the main drawback of this technique is its strong link to the statistics of the image being displayed, which makes the analysis of the displayed image data (in terms of spectral properties of the surface, for example) more complex. For a specific application conducted with a given satellite, this inconvenience could be overcome by using a set of fixed linear combinations View full abstract»

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  • Use of a new high-speed digital data acquisition system in airborne ice-sounding

    Publication Year: 1989 , Page(s): 561 - 567
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1440 KB)  

    A high-speed digital data acquisition and signal averaging system for borehole, surface, and airborne radio-frequency geophysical measurements was designed and built by the US Geological Survey. The system permits signal averaging at rates high enough to achieve significant signal-to-noise- enhancement in profiling, even in airborne applications. The first field use of the system took place in Greenland in 1987 for recording data on a 150 by 150-km grid centered on the summit of the Greenland ice sheet. About 6000-line km were flown and recorded using the new system. The data can be used to site a proposed scientific corehole through the ice sheet View full abstract»

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  • Beaufort-Chukchi seas summer and fall ice margin data from Seasat: conditions with similarities to the Labrador Sea

    Publication Year: 1989 , Page(s): 541 - 551
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1568 KB)  

    The margin of the sea-ice pack of the Beaufort and Chukchi seas is examined using the microwave data from Seasat taken during the summer to early fall, July 4 through October 8, 1978, and the observations are compared to the analogous observations taken in LIMEX'87. The sensors used are synthetic-aperture radar (SAR), the Seasat-A scatterometer system, and the Scanning Multichannel Microwave Radiometer View full abstract»

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  • C-band SAR observations of marginal ice zone rheology in the Labrador Sea

    Publication Year: 1989 , Page(s): 522 - 534
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2516 KB)  

    Synthetic-aperture radar (SAR) imagery collected during the LIMEX'87 field program in the Labrador Sea is used to qualitatively interpret the deformation modes in play throughout the experiment. The ice cover exhibited two distinct rheologies separated by a clear line of shear: a nonlinear viscous outer regime, and a quasi-brittle inner regime. A single constitutive relation capable of effectively modeling both is unlikely within a plastic rate-independent formulation. Rate-dependent effects are discussed in relation to favoring brittle fraction in an otherwise ductile material View full abstract»

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING (TGRS) is a monthly publication that focuses on the theory, concepts, and techniques of science and engineering as applied to sensing the land, oceans, atmosphere, and space; and the processing, interpretation, and dissemination of this information.

 

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Meet Our Editors

Editor-in-Chief
Antonio J. Plaza
University of Extremadura