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IEEE International Conference on image processing

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

ISBN: (纸本)0780385543

Texture is one of important features of masses in mammograms. A recent texture unit-based texture spectrum approach, referred to as texture unit coding (TUC) has shown promise in texture classification. This paper presents a new application of the TUC to mass classification in mammograms. The TUC generates a texture spectrum for a texture image that can be used to describe the characteristics of masses. It also develops an information divergence (ID)-based discrimination criterion to measure the discrepancy between two texture spectra, a concept yet to explore in texture analysis. The TUC along with ID are further applied to mass classification in mammograms where the minimammographic database provided by the Mammographic image Analysis Society (MIAS) is used for experiments.

关键词： Pixel Breast cancer Application software image coding image texture analysis Spatial databases Helium image generation Histograms Shape

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New texture shape feature coding-based computer aided diagnostic methods for classification of masses on mammograms

New texture shape feature coding-based computer aided diagno...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Y. Chen C.-I. Chang Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore MD USA

This work presents new texture shape feature coding (TSFC)-based computer aided diagnostic (CAD) classification methods for classification of masses on mammograms. It introduces a new concept of 1.5-order 3-neighbor 3/spl times/3 connectivity to extract texture shape features that can describe multiples of 22.5/spl deg/. In order to effectively utilize these shape features, two new methods of implementing TFSC are further proposed to convert these features to texture feature numbers (TFNs), TFNs in quaternary (TFNq) which expresses a TFN in quaternary expansion and TFNs in product (TFNx ) that represents a TFN in terms of a product. Both TFNq and TFNx can then produce texture shape histograms in the same way that a gray-level histogram is generated for an image. Such a texture shape histogram is further used to generate various shape features of masses on mammograms for classification. In order to demonstrate the promise of our TSFC-based CAD methods, the MiniMammographic database provided by the Mammographic image Analysis Society (MIAS) is used for experiments.

关键词： Shape Feature extraction Histograms image coding Character recognition remote sensing Signal processing image processing Laboratories computer science

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A uniform projection-based unsupervised classification for hyperspectral imagery

A uniform projection-based unsupervised classification for h...

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： Jing Wang Chein-I Chang Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD USA

ISBN: (纸本)0780387422

Orthogonal subspace projection (OSP) has received considerable interest in hyperspectral image classification. It performs well when the complete knowledge of image endmembers is available. In reality, obtaining such prior knowledge is very difficult, if not impossible. This work investigates a variant of OSP, called uniform projection (UP) and presents a UP-based unsupervised algorithm for hyperspectral image classification. It first implements a uniform target detector (UTD) to find a set of interfering signatures, I, then another uniform I-annihilated detector (UIAD) to find desired target signatures. The signatures in I are combined with the UIAD found desired signatures to form a target signatures matrix M which can be used for supervised image classification. In this case, OSP can be used for this purpose. In order to demonstrate the utility of the proposed unsupervised classification technique for hyperspectral imagery, a series of computer simulations and experiments are conducted for analysis.

关键词： Hyperspectral imaging Data mining Hyperspectral sensors image classification Detectors Histograms remote sensing Signal processing image processing Laboratories

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Failure mechanism of variable frequency drives in ungrounded distribution systems

Failure mechanism of variable frequency drives in ungrounded...

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2004 11th International Conference on Harmonics and Quality of Power

作者： Venkateswaran, Mahesh M. Lunder, David Baghzouz, Yahia Department of Electrical and Computer Engineering University of Nevada Las Vegas NV 89154 United States Bechtel Nevada DOE's Remote Sensing Laboratory Nellis Air Force Base NV

ISBN: (纸本)0780387465

This paper investigates an actual violent failure of a number of variable frequency drives that were supplied by an ungrounded power source. It was noted that when a phase-to-ground fault was manifested in one of the motors, all the VFDs were destroyed except the one that is connected to the motor where the fault occurs. Circuit analysis and simulations using PSpice was carried out in an effort to explain the cause of such destruction. It is found that the inverters used in this facility were not designed for ungrounded power supplies, and the cause of such failure is the presence of an EMI capacitor filter that is placed between the DC link midpoint and ground. © 2004 IEEE.

关键词： Variable speed drives

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Discrimination and identification for subpixel targets in hyperspectral imagery

Discrimination and identification for subpixel targets in hy...

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IEEE International Conference on image processing

作者： Chein-I Chang Weimin Liu Chein-Chi Chang Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore MD USA Department of Civil and Environmental Engineering University of Maryland Baltimore MD USA

ISBN: (纸本)0780385543

Spectral measures have been used in material identification and discrimination. They are effective if the spectral signatures are calibrated and not contaminated. However, it may not be true in many real applications, specifically, for mixed pixels and subpixel targets. This paper investigates the issue of discrimination and identification for subpixel targets and further develops sample spectral covariance/correlation matrix-based hyperspectral measures to account for spectral variability within subpixel targets. Two types of measures are of interest and studied, Mahalanobis distance-based hyperspectral measures and matched filter-based hyperspectral measures. In order to substantiate the proposed measures, a real data-based comparative analysis is conducted and compared to two spectral similarity measures, spectral angle mapper (SAM) and spectral information divergence (SID) for performance evaluation. The experiments show that both Mahalanobis distance-based hyperspectral measures and matched filter-based hyperspectral measures work very effectively and outperformed the SAM and the SID in discrimination and identification for subpixel targets.

关键词： Hyperspectral imaging Pollution measurement Hyperspectral sensors Covariance matrix Matched filters Performance analysis Performance evaluation remote sensing Signal processing image processing

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Validation of ocean surface wind vector sensing using combined active and passive microwave measurements

Validation of ocean surface wind vector sensing using combin...

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： S. Soisuvarn W.L. Jones T. Kasparis Central Florida Remote Sensing Laboratory Electrical and Computer Engineering Department University of Central Florida Orlando FL USA

A new ocean surface wind vector measurement has been developed using combined active and passive microwave measurements from the TRMM satellite. In this method, collocated ocean normalized radar backscatter from the Precipitation Radar (PR) and retrieved wind speeds from the TRMM Microwave imager (TMI) are used to derive ocean wind direction. Since PR provides only a single azimuth look, multiple wind direction solutions exists; but we compare the "closest" retrieved wind direction with near-simultaneous surface truth from three ocean buoy networks, namely; National Data Buoy Center (NDBC), Tropical Atmosphere Ocean (TAO), and Pilot Research moored Array in the Tropical Atlantic (PIRATA). Comparisons are also presented for QuikSCAT wind vector retrievals.

关键词： Oceans Sea surface Microwave measurements Sea measurements Radar imaging Spaceborne radar Satellites Backscatter image retrieval Wind speed

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Application of QuikSCAT radiometer rain rates to near-real-time global precipitation estimates: a global precipitation mission pathfinder

Application of QuikSCAT radiometer rain rates to near-real-t...

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： K.A. Ahmad W.L. Jones T. Kasparis Central Florida Remote Sensing Laboratory Department of Electrical and Computer Engineering University of Central Florida Orlando FL USA

The SeaWinds scatterometer onboard the QuikSCAT satellite simultaneously measures the polarized microwave brightness temperature of the ocean/atmosphere. QuikSCAT Radiometer (QRad) brightness temperatures are used to infer instantaneous oceanic rain rates using a statistical retrieval algorithm that has been developed using collocated QRad brightness temperatures with TRMM Microwave imager (TMI) rain rate measurements. The algorithm produces earth-located instantaneous rain rate binned in 0.5 hour universal time windows and produced on a 50-km earth grid. The orbit of QuikSCAT allows independent rain temporal sampling that can be used to improve the estimation of global rainfall in 3 hour windows, which is a goal of the future Global Precipitation Mission (GPM). In this work, QRad retrieved rain rate examples are presented and comparisons are made with the TRMM 3B42RT near real time product. Results demonstrate that QRad rain measurements agree well with these independent microwave rain observations and superior to the visible/infrared rain estimates, which demonstrates the utility of adding QRad to the 3B42RT product.

关键词： Rain Microwave measurements Extraterrestrial measurements Sea measurements Brightness temperature Microwave radiometry Atmospheric measurements Radar measurements Satellite broadcasting Polarization

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Failure mechanism of variable frequency drives in ungrounded distribution systems

Failure mechanism of variable frequency drives in ungrounded...

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International Conference on Harmonics and Quality of Power

作者： M.M. Venkateswaran D. Lunder Y. Baghzouz Department of Electrical and Computer Engineering University of Nevada Las Vegas NV USA DOE's Remote Sensing Laboratory NV USA Bechtel Nevada at the DOE's Remote Sensing Laboratory NV

This work investigates an actual violent failure of a number of variable frequency drives that were supplied by an ungrounded power source. It was noted that when a phase-to-ground fault was manifested in one of the motors, all the VFDs were destroyed except the one that is connected to the motor where the fault occurs. Circuit analysis and simulations using PSpice was carried out in an effort to explain the cause of such destruction. It is found that the inverters used in this facility were not designed for ungrounded power supplies, and the cause of such failure is the presence of an EMI capacitor filter that is placed between the DC link midpoint and ground.

关键词： Failure analysis Frequency Drives Circuit faults Circuit analysis Analytical models Circuit simulation Inverters Power supplies Electromagnetic interference

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Real-time vision-based approach for probe tracking in operating room

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International Congress Series 2004年 1268卷 467-472页

作者： Aly A. Farag M.Sabry Hassouna Ayman El-Baz S. Hushek Computer Vision and Image Processing Laboratory Electrical and Computer Engineering University of Louisville 403 Lutz Hall Bldg. Louisville KY 40292 USA Department of Neurological Surgery University of Louisville USA

A hand-held surgical probe is an essential component of any image-guided neurosurgery (IGNS). During the surgical procedure, the IGNS tracks the probe position and displays the anatomy beneath it as three orthogonal image slices on a workstation-based 3D imaging system. Existing IGNS systems use different tracking techniques including mechanical, optical, ultrasonic, and electromagnetic systems. In this paper, we present a new computational vision-based probe tracking technique, which provides both position and orientation. We also propose another new computational vision-based technique to track the patient head and thus compensate for its movement during probing procedure. The proposed system is completely passive, its stereo cameras detect the presence of the probe using available visible light, and reports on their exact location and orientation in patient physical space in real time. We have validated the system using a skull phantom and a hand made probe.

关键词： image-guided neurosurgery Head motion tracking Probe tracking Vision tracking

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A Revisit to Target-Constrained Interference-Minimized Filter (TCIMF)

A Revisit to Target-Constrained Interference-Minimized Filte...

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Imaging Spectrometry IX

作者： Chang, Chein-I Ren, Hsuan Hsueh, Mingkai Du, Qian D'Amico, Francis M. Jensen, James O. Remote Sensing Sign./Image Proc. L. Department of Computer Science Univ. of Maryland Baltimore County Baltimore MD 21250 US Army Edgewood Chem. and Biological Center Aberdeen Proving Ground MD 21010 Department of Electrical Engineering Texas A and M University-Kingsville Kingsville TX 78363

The Orthogonal Subspace Projection (OSP) and Constrained Energy Minimization (CEM) have been used in hyperspectral target detection and classification. A target-constrained interference-minimized, filter (TCIMF) was recently proposed to extend the CEM to improve signal detectability by annihilating undesired target signal sources as the way carried out in the OSP. In this paper, we revisit the TCIMF from a signal processing viewpoint where signals can be characterized by three types of information sources, desired target sources and undesired target sources, both of which are provided a priori, and interferers which are unknown interfering sources. By virtue of such signal decomposition, we can show that the TCIMF is actually a generalization of the OSP and CEM. In particular, we investigate assumptions made for the OSP and CEM in terms of these three types of signal sources and exploit insights into their filter design. As will be shown in this paper, the OSP and the CEM perform the same tasks by operating different levels of information and both can be viewed as special cases of the TCIMF.

关键词： image processing

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