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IEEE International Symposium on Biomedical Imaging

作者： Alireza Akhondi Asl Hamid Soltanian-Zadeh School of Cognitive Sciences Institute of Studies in Theoretical Physics and Mathematics Tehran Iran Control and Intelligent Processing Center of Excellence (CIPCE) School of Electrical and Computer Engineering University of Tehran Tehran Iran Image Analysis Laboratory Radiology Department Henry Ford Health System Detroit MI USA

We propose a constrained, three-dimensional, nonparametric, entropy-based, coupled, multi-shape approach to segment subcortical brain structures from magnetic resonance images (MRI). The proposed method uses PCA to develop shape models that capture structural variability. It integrates geometrical relationship between different structures into the algorithm by coupling them (limiting their independent deformations). On the other hand, to allow variations among coupled structures, it registers each structure separately when building the shape models. It defines an entropy-based energy function, which is minimized using quasi-Newton algorithm. To this end, probability density functions (pdf) are estimated iteratively using nonparametric Parzen window method. In the optimization algorithm, constraints are used to improve segmentation quality. These constraints are extracted from training data. Sample results are given for the segmentation of caudate, hippocampus, and putamen, illustrating highly superior performance of the proposed method compared to the most similar methods in the literature.

关键词： Constraint optimization Brain Iterative algorithms image segmentation Shape Couplings Magnetic resonance Magnetic resonance imaging Principal component analysis Buildings

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A Vegetation Correction Methodology Applied for Soil Moisture Retrieval from C-Band Radar Observations

A Vegetation Correction Methodology Applied for Soil Moistur...

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： A. T. Joseph P. E. O'Neill R. van der Velde R. Lang T. Gish NASA Goddard Space Flight Center Greenbelt MD USA International Institute of Geo-Information Science and Earth Observation Enschede Netherlands Department of Electrical and Computer Engineering George Washington University Washington D.C. DC USA Hydrology & Remote Sensing Laboratory USDA-ARS Beltsville MD USA

This research presents a methodology to correct backscatter (sigmadeg) observations for vegetation effects. The proposed methodology is based on the concept that the ratio between the surface scattering over the total amount of scattering (sigmadeg surface /sigmadeg soil ) is affected only by the vegetation and can be described as a function of the vegetation water content. The data set used in this study was collected at USDA's Optimizing Production Inputs for Economic and Environmental Enhancement (OPE 3 ) experimental site in Beltsville, Maryland (USA) over a corn growth cycle in 2002 and includes C-band (4.75 GHz) HH- and VV-polarized observations acquired at incidence angles of 15, 35 and 55 degrees. During this period the corn crops reached peak biomass of 6.6 kg m -2 and a soil moisture range varying from 0.02 to 0.26 cm 3 cm -3 . The results show that through application of the proposed vegetation correction methodology the soil moisture retrieval accuracy can be improved from 0.033 to 0.032 cm 3 cm -3 , 0.049 to 0.033 cm 3 cm -3 , and 0.079 to 0.047 cm 3 cm -3 at incidence angles of 15, 35 and 55 degrees, respectively.

关键词： Soil moisture Vegetation mapping Soil measurements Biomass Moisture measurement Radar scattering US department of Agriculture Radar measurements Surface soil Production

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Marine Doppler Radar Surface Current Measurements in the Surf Zone

Marine Doppler Radar Surface Current Measurements in the Sur...

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2008 IEEE/OES 9th Working Conference on Current Measurement Technology: Advances in Current and Wave Measurement

作者： Dragana Perkovic Stephen J. Frasier Thomas C. Lippmann Microwave Remote Sensing Laboratory Electrical and Computer Engineering University of Massachusetts Amherst MA USA Department of Civil and Environmental Engineering Ohio State Uinversity Columbus OH USA

This paper presents a comparison of microwave radar surface velocity estimates to the estimates derived from video observations in the surf zone. The data presented here were collected during the Nearshore Canyon Experiment (NCEX) in the fall of 2003. The radar estimates are inferred from the Doppler shift of the backscattered radiation while video velocity estimates were produced using Particle image Velocimetry (PIV) technique. Comparisons of long-shore velocity estimates show high spatial correlation within the central surf zone. The comparisons of the near cross-shore velocity shows the importance of bore velocity removal while showing high spatial correlation when the bias is removed. Both alongshore and cross-shore velocity estimates display discrepancies in the breaker and the swash zones.

关键词： Doppler radar Current measurement remote sensing Radar imaging Instruments Sea surface Radar remote sensing Sea measurements Sensor arrays Laser radar

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Microwave Soil Moisture Retrieval Under Trees

Microwave Soil Moisture Retrieval Under Trees

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： Peggy O'Neill Roger Lang Mehmet Kurum Alicia Joseph Michael Cosh Thomas Jackson Hydrological Sciences Branch / Code 614.3 NASA Goddard Space Flight Center Greenbelt MD USA Dept. of Elec. & Computer Engineering George Washington University Washington D.C. Washington DC USA Department of Electrical & Computer Engineering George Washington University Washington D.C. DC USA USDA-ARS Hydrology and Remote Sensing Laboratory Beltsville MD USA

During 2007 a field experiment was conducted with a goal of optimizing microwave soil moisture retrieval algorithms for small to medium deciduous trees. After initial field checkout in Fall 2006, the ComRAD microwave truck instrument system was deployed to a test site with several stands of deciduous paulownia trees. A joint effort of NASA/GSFC and George Washington University, ComRAD consists of a quad-polarized 1.25 GHz radar and a dual-polarized 1.4 GHz radiometer sharing the same antenna. ComRAD can function as a ground-based instrument simulator for L band space missions such as SMOS, SMAP, and Aquarius. In the current study, ComRAD acquired data from April to November 2007 to monitor the seasonal difference in microwave response to soil moisture under deciduous trees. To conclude the three-year planned field measurement effort, ComRAD will deploy to a natural coniferous pine tree site in 2008.

关键词： Soil moisture Instruments Radar antennas System testing NASA Microwave radiometry Space missions SMAP mission Monitoring Soil measurements

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Chesapeake bay water quality monitoring using satellite imagery

Chesapeake bay water quality monitoring using satellite imag...

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作者： Ramakrishna, Bharath Chang, Chein-I. Trou, Bruce Henqemihle, Jerry Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD 21250 Microtel LLC 111 Centerway Greenbelt MD 20770

The Chesapeake Bay is a valued ecological, economic, recreational, cultural and scenic resource. The Bay watershed States and the District of Columbia, in conjunction with the EPA Chesapeake Bay Program, have worked and teamed together over the past 20 years to protect and restore the Bay ecosystem. A key component of this effort is water quality and habitat monitoring to assess the impact of management actions and natural, processes, and evaluate habitat parameters on living resources such as submerged aquatic vegetation (SAV), oysters, and fisheries. Using aerial and satellite remote sensing imagery has become a practical and effective means of monitoring water quality in a timely manner. Of particular interest in evaluation of water clarity are several initiative measures. Specifically, Secchi-Disk Transparency (SDT) and Chlorophyll α (Chl-α) have been widely accepted as critical indicators of water quality and their reliable estimation using satellite imagery provides a cost effective and speedy means for water quality monitoring. Work done at Water Resources Center, University of Minnesota has demonstrated the feasibility of performing regional assessment of lake water quality using LANDSAT image data. This paper investigates an approach similar to their work but uses a different type of satellite imagery, EO-1 ALI imagery where the SDT and Chl-a are also used as indicators to estimate water quality for the Chesapeake Bay and DC area (Potomac River). In doing so, three major issues are investigated, which are (1) the study site that is an open Bay area, not a self-contained lake;(2) investigation of applicability of equations that are used to specify the SDT and Chl-α to our Bay area study;(3) the use of a different type of satellite imagery for water quality monitoring. This paper develops techniques to address these three issues and presents preliminary experiments which show encouraging results. © World Scientific Publishing Company.

关键词： Water quality

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Does an endmember set really yield maximum simplex volume?

Does an endmember set really yield maximum simplex volume?

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2007 IEEE International Geoscience and remote sensing Symposium, IGARSS 2007

作者： Wu, Chao-Cheng Chang, Chein-I IEEE Department of Computer Science Remote Sensing Signal and Image Processing Laboratory University of Maryland Baltimore County Baltimore MD United States

ISBN: (纸本)1424412129

One of commonly used criteria for finding an endmember set is to assume that for a given number of endmembers, p, ap-vertex simplex with its vertices specified byp endmembers always yields the maximum volume. Since there are also other criteria which have been widely used for endmember extraction, the issue of interest is "does an endmember set really produce a simplex with maximum volume?" In other words, using the criterion of a simplex with maximum volume is a better and more effective measure than other criteria currently being used by endmember extraction such as orthogonal projection-based pixel purity index (PPI), fully constrained least squares-based spectral unmixing, etc. This paper explores this issue by investigating a number of popular endmember extraction algorithms which are designed by different criteria. An extensive experiment-based study is also conducted for comparative analysis. © 2007 IEEE.

关键词： remote sensing

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Performance of a self-paced brain computer interface on data contaminated with eye-movement artifacts and on data recorded in a subsequent session

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Computational Intelligence and Neuroscience 2008年第unknown期2008卷 1-13页

作者： Fatourechi, Mehrdad Ward, Rabab K. Birch, Gary E. Image and Signal Processing Laboratory Department of Electrical and Computer Engineering University of British Columbia Vancouver BC V6T 1Z4 Canada Institute for Computing Information and Cognitive Systems University of British Columbia Vancouver BC V6T 1Z4 Canada Neil Squire Society Burnaby BC V5M 3Z3 Canada

The performance of a specific self-paced BCI (SBCI) is investigated using two different datasets to determine its suitability for using online: (1) data contaminated with large-amplitude eye movements, and (2) data recorded in a session subsequent to the original sessions used to design the system. No part of the data was rejected in the subsequent session. Therefore, this dataset can be regarded as a pseudo-online test set. The SBCI under investigation uses features extracted from three specific neurological phenomena. Each of these neurological phenomena belongs to a different frequency band. Since many prominent artifacts are either of mostly low-frequency (e.g., eye movements) or mostly high-frequency nature (e.g., muscle movements), it is expected that the system shows a fairly robust performance over artifact-contaminated data. Analysis of the data of four participants using epochs contaminated with large-amplitude eye-movement artifacts shows that the system's performance deteriorates only slightly. Furthermore, the system's performance during the session subsequent to the original sessions remained largely the same as in the original sessions for three out of the four participants. This moderate drop in performance can be considered tolerable, since allowing artifact-contaminated data to be used as inputs makes the system available for users at ALL times.

关键词： .Brain computer Data Contaminated Eye-Movement Artifacts Subsequent Session Recorded in Subsequent SBCI contaminated with large-amplitude neurological phenomena

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Does an endmember set really yield maximum simplex volume?

Does an endmember set really yield maximum simplex volume?

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： Chao-Cheng Wu Chein-I Chang Remote Sensing Signal and Image Processing Laboratory the Department of Computer Science and Electrical Engineering Department University of Maryland Baltimore MD USA

One of commonly used criteria for finding an endmember set is to assume that for a given number of endmembers, p, a p-vertex simplex with its vertices specified by p endmembers always yields the maximum volume. Since there are also other criteria which have been widely used for endmember extraction, the issue of interest is "does an endmember set really produce a simplex with maximum volume?" In other words, using the criterion of a simplex with maximum volume is a better and more effective measure than other criteria currently being used by endmember extraction such as orthogonal projection-based pixel purity index (PPI), fully constrained least squares-based spectral unmixing, etc. This paper explores this issue by investigating a number of popular endmember extraction algorithms which are designed by different criteria. An extensive experiment-based study is also conducted for comparative analysis.

关键词： Algorithm design and analysis Least squares methods Hyperspectral imaging Indexes Volume measurement Chaos Data mining Subspace constraints Computational efficiency Current measurement

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CHESAPEAKE BAY WATER QUALITY MONITORING USING SATELLITE imageRY

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International Journal of High Speed Electronics and Systems 2007年第4期17卷 681-688页

作者： BHARATH RAMAKRISHNA CHEIN-I CHANG BRUCE TROU JERRY HENQEMIHLE Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD 21250 USA Microtel LLC 111 Centerway Greenbelt MD 20770 USA

The Chesapeake Bay is a valued ecological, economic, recreational, cultural and scenic resource. The Bay watershed States and the District of Columbia, in conjunction with the EPA Chesapeake Bay Program, have worked and teamed together over the past 20 years to protect and restore the Bay ecosystem. A key component of this effort is water quality and habitat monitoring to assess the impact of management actions and natural processes, and evaluate habitat parameters on living resources such as submerged aquatic vegetation (SAV), oysters, and fisheries. Using aerial and satellite remote sensing imagery has become a practical and effective means of monitoring water quality in a timely manner. Of particular interest in evaluation of water clarity are several initiative measures. Specifically, Secchi-Disk Transparency (SDT) and Chlorophyll a (Chl- a ) have been widely accepted as critical indicators of water quality and their reliable estimation using satellite imagery provides a cost effective and speedy means for water quality monitoring. Work done at Water Resources Center, University of Minnesota has demonstrated the feasibility of performing regional assessment of lake water quality using LANDSAT image data. This paper investigates an approach similar to their work but uses a different type of satellite imagery, EO-1 ALI imagery where the SDT and Chl- a are also used as indicators to estimate water quality for the Chesapeake Bay and DC area (Potomac River). In doing so, three major issues are investigated, which are (1) the study site that is an open Bay area, not a self-contained lake; (2) investigation of applicability of equations that are used to specify the SDT and Chl- a to our Bay area study; (3) the use of a different type of satellite imagery for water quality monitoring. This paper develops techniques to address these three issues and presents preliminary experiments which show encouraging results.

关键词： Chesapeake Bay EO-1 ALI imagery Secchi Depth (SDT) Chl- a

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Wavelet-based despeckling of SAR images using Gauss-Markov random fields

Wavelet-based despeckling of SAR images using Gauss-Markov r...

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作者： Gleich, Dušan Datcu, Mihai IEEE Laboratory for Signal Processing and Remote Control Faculty of Electrical Engineering and Computer Science University of Maribor 2000 Maribor Slovenia Remote Sensing Technology Institute IMF 82234 Weßling Germany Paris Institute of Technology GET Telecom Paris University Politechnica of Bucharest Bucharest Romania

In this paper, a wavelet-based speckle-removing algorithm is represented and tested on synthetic aperture radar (SAR) images. The SAR image is first transformed using a dyadic wavelet transform. The noise in the wavelet-transformed image is modeled as an additive signal-dependent noise with Gaussian distribution. The distribution of a noise-free image in a wavelet domain is modeled as a generalized Gauss-Markov random field (GGMRF). An unsupervised stochastic model-based approach to image denoising is represented. If the observed area is homogeneous, the parameters of the Gaussian distribution and GGMRFs are estimated from incomplete data using mixtures of wavelet coefficients. An expectation-maximization algorithm is used to estimate the parameters of both noisy and noise-free images. The unknown parameters are estimated using image and noise models that are defined in the wavelet domain for heterogeneous areas. Different inter- and intrascale dependences of wavelet coefficients were used to estimate the unknown parameters. The represented wavelet-based method efficiently removes noise from SAR images. © 2007 IEEE.

关键词： Radar imaging

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