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2008 IEEE International Geoscience and remote sensing Symposium - Proceedings

作者： Morstad, Daniel L. Helder, Dennis L. Image Processing Laboratory South Dakota State University SD 57007 United States Electrical Engineering and Computer Science Department South Dakota State University SD 57007 United States

ISBN: (纸本)9781424428083

Over the past several years, pseudo-invariant sites for trending the radiometric gain of multispectral satellite imaging systems has proven to be very useful and accurate. For example, the lifetime calibration of the Landsat 5 Thematic Mapper (TM) was recently updated based in large part upon this approach. This effort reduced the error in the gain estimate from roughly 13 percent to less than 5 percent and integrated a variety of absolute calibration estimates for the sensor [1]. Typically, pseudo-invariant sites are located in arid regions where very little temporal and spatial change occurs over long periods of time and significant extent. Sites in the Sahara desert are especially attractive. However, drawbacks of this approach are that the sites are relatively unacceptable and, for some instruments, only limited numbers of data sets are available. As a result, it would be helpful to use sites that are observed often, such as locations in North America, so that the technique could be applied to more sensors both historically and in the future. The drawback to these sites is that they are typically of much smaller extent and, therefore, are more difficult to use from a geometric perspective. Recent work has shown that small pseudo-invariant sites, if carefully chosen, can also be used for accurate trending of satellite instruments. This paper will illustrate an approach that suggests the calibration site commonly known as Sonoran Desert can be used to observe the characteristic calibration curve of Landsat 5 TM. Because of the significant number of observations of this site, and other similar sites in North America, there is good potential to extend this technique to additional multispectral instruments for enhanced long term monitoring of radiometric gain. © 2008 IEEE.

关键词： Landsat

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A PYRAMID-BASED BLOCK OF SKEWERS FOR PIXEL PURITY INDEX FOR ENDMEMBER EXTRACTION IN HYPERSPECTRAL imageRY

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International Journal of High Speed Electronics and Systems 2008年第2期18卷 469-482页

作者： CHEIN-I CHANG MINGKAI HSUEH WEIMIN LIU CHAO-CHENG WU FARZEEN CHAUDHRY GREGORY SOLYAR ANTONIO PLAZA Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD 21250 USA Computer Science Department University of Extremadura Avda. de la Universidad s/n 10.071 Caceres Spain

Pixel Purity Index (PPI) has been widely used for endmember extraction. Recently, an approach using blocks of skewers was proposed by Theiler et al., called blocks of skewers (BOS) method, to improve computation of the PPI. It utilizes a block of skewers to reduce number of calculations of dot products operated by the PPI on each skewers with all data sample vectors. Unfortunately, the BOS method also suffers from the same drawbacks that the PPI does in terms of several parameters which are needed to be determined a priori . Besides, it also has an additional parameter, block size, B needed to be determined where no guideline is provided of how to select this parameter. In this paper, the BOS method is also investigated. Most importantly, a new pyramid-based block design for the BOS method is also introduced as opposed to the cube-based block designed used by Theiler et al.'s BOS. One major advantage of our proposed pyramid-based BOS over Theiler et al.'s cube-design BOS is the hardware design for Field Programmable Gate Arrays (FPGAs) implementation.

关键词： Blocks of skewers (BOS) method Field Programmable Gate Arrays (FPGAs) Pixel purity index (PPI)

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Vertical Velocity Turbulence Observed with FMCW Radar

Vertical Velocity Turbulence Observed with FMCW Radar

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： S. J. Frasier A. Muschinski P.-S. Tsai M. Behn Microwave Remote Sensing Laboratory Department of Electrical & Computer Engineering University of Massachusetts Amherst MA USA

Very fine space and time resolution observations of clear air reflectivity and vertical velocity were obtained in a day-time convective boundary layer by a frequency-modulated continuous-wave radar. Historically, most atmospheric FMCW radar investigations have focused on the extremely fine range resolution of which such radars are capable. When used in this mode, Doppler velocity information is usually lost due to the long integration time of the frequency sweep. That is, the effective pulse repetition frequency of the radar is so low that the Nyquist velocity interval is too narrow for useful measurements of atmospheric velocities. However, when configured for rapid profiling at the expense of either height coverage or spatial resolution, FMCW radars are capable of obtaining Doppler velocity timeseries from moderately sized resolution volumes at rates of several Hz. These are sufficient to resolve turbulent velocity variations in the inertial subrange down to timescales of approximately one second or less.

关键词： Doppler radar Frequency Spatial resolution Reflectivity Poles and towers Pulse measurements Radar remote sensing Atmospheric measurements Radar scattering Radar antennas

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A Ka-band Interferometer for Cryospheric Applications-Instrument Description and First Results

A Ka-band Interferometer for Cryospheric Applications-Instru...

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： Harish Vedantham Paul R. Siqueira Karthik Srinivasan Edin Insanic Microwave Remote Sensing Laboratory (MIRSL) Department of Electrical and Computer Engineering University of Massachusetts Amherst MA USA

Characterization of the Earth's oceanic and cryospheric topography is among NASA's strategic goals for the next decade. An effective technique for achieving such measurements is radar interferometry. For this technology, use of mm-wave frequencies (Ku- and Ka-band) is appealing due to the proportional size of the space borne structure to the observing wavelength and minimal snow penetration. At such high frequencies, achieving stability in instrument performance and the mechanical deployment structure for accurate measurements is an engineering challenge. To address this, the Microwave remote sensing laboratory at the University of Massachusetts is developing a high performance Ku- and Ka-band interferometer as a prototype for a space borne instrument. The interferometer will be used in a scaled-down ground-based configuration. This paper presents an instrument description of the Ka-band interferometer (the down-converter in particular) and first results from its performance evaluation.

关键词： Instruments Sea measurements Wavelength measurement Space technology Frequency Earth Surfaces Radar interferometry Marine technology Snow

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Use of Vector Velocity Estimate Accuracy for Improved Resource Allocation in a Network of Doppler Radars

Use of Vector Velocity Estimate Accuracy for Improved Resour...

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： Edin Insanic Paul Siqueira Amherst Department of Electrical and Computer Engineering Microwave Remote Sensing Laboratory University of Massachusetts Amherst MA USA

To help optimize the real time scanning of an adaptive radar network, it is necessary to define a performance metric for weighing the competing scanning tasks. A point volume vector velocity estimation methodology can be used in this context to derive the confidence bounds of the vector velocity estimator that can, in turn, be utilized as a quality indicator in devising scanning strategies. This document presents the basic derivation of this estimation process and provides examples of processed weather moment data.

关键词： Resource management Doppler radar Velocity measurement Radar measurements Meteorological radar Vectors Covariance matrix Atmosphere Measurement errors Particle measurements

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Velocity Unfolding in Networked Radar System

Velocity Unfolding in Networked Radar System

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： Edin Insanic Paul Siqueira Department of Electrical and Computer Engineering Microwave Remote Sensing Laboratory University of Massachusetts Amherst Amherst MA USA

This paper presents an algorithm that derives the vector velocity estimate in a radar network environment considering the velocities that exceed the maximum unambiguous velocity of its observing sensor nodes. At first, an analytical derivation with underlying assumptions is presented and then simulation results are shown and discussed. This unfolding vector velocity algorithm is based on maximum likelihood theory operating on the first three weather radar spectral moments and can potentially provide a real time velocity detection of broader range of velocities than given by the nodal maximum unambiguous velocity.

关键词： Doppler radar Pulse measurements Radio frequency Maximum likelihood detection Maximum likelihood estimation Meteorological radar Velocity measurement Radar remote sensing Radar detection Atmosphere

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TerraSAR-X: Complex image Inversion for Feature Extraction

TerraSAR-X: Complex Image Inversion for Feature Extraction

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： Matteo Soccorsi Mihai Datcu Dusan Gleich German Aerospacec Center Remote Sensing Technology Institute Wessling Germany Laboratory for Signal Processing and Remote Control Faculty of Electrical Engineering and Computer Science University of Maribor Slovenia

In this paper we present two algorithms for information extraction from Single Look Complex (SLC) Synthetic Aperture Radar (SAR) images. The first algorithm is based on Tikhonov regularization with Total Variation (TV) and a Point-Based Feature (PBF) term. Based on the equivalence of Tikhonov and the Bayesian estimate, the second algorithm is a Maximum A Posteriori (MAP) estimation with a complex-valued Gauss-Markov Random Field (GMRF) in addition to the TV prior. The first algorithm produces a despeckled image preserving fine details and texture. The second algorithm gives a denoised image and in addition the estimated feature parameter vector thetas.

关键词： Feature extraction Synthetic aperture radar Signal processing algorithms TV Bayesian methods image restoration Adaptive filters Cost function Anisotropic magnetoresistance Speckle

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Implementation of Pulse Compression on an Airborne Scatterometer

Implementation of Pulse Compression on an Airborne Scatterom...

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： John J. McManus Stephen J. Frasier James R. Carswell Microwave Remote Sensing Laboratory Department of Electrical & Computer Engineering University of Massachusetts Amherst MA USA Remote Sensing Solutions P.O. Box 1092 Barnstable MA 02630

The pulse compression scheme implemented on the Imaging Wind and Rain Airborne Profiler (IWRAP) is described. Developed at the UMASS Microwave remote sensing laboratory (MIRSL), IWRAP is a dual-band (C and Ku) conically scanning Doppler scatterometer designed to map the atmospheric boundary layer wind fields, ocean surface wind fields, and precipitation within tropical cyclones. IWRAP has previously been deployed using a pulsed transmit waveform with a peak transmit power of 80 watts. This limits the average transmit power and sensitivity for the system which affects the more distant range gates (especially at Ku-band). As a result, IWRAP could operate only at lower altitudes (approx. 5000 ft) causing safety concerns and limiting the missions for which it can be deployed. Increasing sensitivity was achieved by converting IWRAP to a pulse compression radar system. Pulse compression is a technique that combines the increased energy of a longer pulse with the high resolution of a short pulse by implementing a frequency modulated (FM) "chirped" transmit wave-form. This method requires advanced signal processing, in which the received signal is passed through a matched filter to compress the pulse on the receiving end. A system with various chirp/filtering schemes which UMASS has recently developed will be discussed in this paper.

关键词： Pulse compression methods Radar measurements Pulse modulation Frequency modulation Chirp Microwave imaging Rain remote sensing Laboratories Dual band

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Gradient Optimization for multiple kernel's parameters in support vector machines classification

Gradient Optimization for multiple kernel's parameters in su...

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： A. Villa M. Fauvel J. Chanussot P. Gamba J. A. Benediktsson Telecommunications & Remote Sensing Laboratory Department of Electronics University of Pavia Italy Department of Electrical and Computer Engineering University of Iceland Iceland Haskoli Islands Reykjavik IS

The subject of this work is the model selection of kernels with multiple parameters for support vector machines (SVM), with the purpose of classifying hyperspectral remote sensing data. During the training process, the kernel parameters need to be tuned properly. In this work a gradient descent based algorithm is used to estimate the parameters. The selection of multiple parameters is addressed, and an approach based on the analysis of the variance values of individual bands was proposed. Several state of the art kernels were tested. Experiments were conducted on real hyperspectral data. Results obtained with the different approaches/kernels were compared statistically, and showed good results in terms classification accuracies and processing time.

关键词： Kernel Support vector machine classification Hyperspectral sensors Hyperspectral imaging remote sensing Support vector machines Testing image sensors Laboratories Telecommunication computing

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Combining Lidar and InSAR Observations over the Harvard and Duke Forests for Making Wide Area Maps of Vegetation Height

Combining Lidar and InSAR Observations over the Harvard and ...

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： Paul Siqueira Scott Hensley Bruce Chapman Razi Ahmed Microwave Remote Sensing Laboratory Department of Electrical and Computer Engineering University of Massachusetts Amherst MA USA Radar Science and Engineering Jet Propulsion Laboratory Pasadena CA USA

In this paper, two data sets consisting of co-located full-waveform lidar and InSAR observations are discussed, one over the Duke Forest, near Durham, North Carolina, and the other, the Harvard Forest, located in Western Massachusetts. Data for the Duke forest consists of AIRSAR and GeoSAR (both airborne sensors) interferometric SAR observations spanning in frequency from X-band down to P-band, and data from the GSFC's SLICER instrument. For the Harvard Forest, spaceborne data from JAXA's ALOS/PALSAR mission is used in conjunction with GSFC's LVIS instrument. Early work with SLICER and GeoSAR data has used a lookup table approach for generating a table that correlates the InSAR observables of differential height between X-and P-band observations, and X-band correlation magnitude to lidar derived height. This table was then used for estimating heights over the remaining swath, where lidar data was not available. A similar technique can be used for spaceborne data, in this case, over the Harvard Forest. In this paper, the comparison between lidar observations and the InSAR Duke observations are shown, and then followed by a preliminary treatment highlighting relationships in the ALOS/PALSAR Harvard data that can be exploited for similar purposes.

关键词： Laser radar Synthetic aperture radar interferometry Vegetation mapping Table lookup Spaceborne radar Instruments L-band Volume measurement remote sensing Laboratories

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