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IEEE International Ultrasonics Symposium

作者： Juan Lu Ramazan Demirli Jafar Saniie Embedded Computing and Signal Processing Laboratory Department of Electrical and Computer Engineering Illinois Institute of Technology Chicago United States Center for Advanced Communications Villanova University Pennsylvania United States

ISBN: (纸本)9781467398985

The ultrasonic signals backscattered from multilayered materials using a pulse-echo method are inherently low-resolution due to the band-limited nature of the interrogating transducer. To improve resolution, the Wiener Filter (WF) based solutions have been used traditionally, although they provide limited improvement and are highly sensitive to noise. More recently, sparse deconvolution techniques (e.g., l1-regularized Least Squares Deconvolution (l1-LSD)) have proved to be effective in improving the resolution;however, they are highly dependent on pulse invariance. It is common for an ultrasonic wavelet to change its shape as it propagates through the materials due to frequency dependent attenuation, scattering and dispersion. Consequently, these changes in pulse shape limit the application of these algorithms which need a prior knowledge of pulse-wave of the system. In this paper we present an adaptive and highly efficient deconvolution technique, Cepstrum Sparse Deconvolution (CSD), which does not require any prior information of the system or the detected object but compensates for the pulse-wave variation by estimating the fundamental pulse-wave shape directly from the backscattered signal. This pulse-wave estimation is based on cepstrum processing of the signal prior to the deconvolution process. Applications and comparisons are made to evaluate the performance of CSD, WF and l1-LSD through experimental and simulated ultrasound data which contain varying-shape wavelets with respect to amplitude, center frequency, arrival time, bandwidth, and phase parameters. The Normalized Mean Absolute Score (NMAS) index, a measure of distance between the actual reflectivity function and the estimated function is used to evaluate these algorithms' performance. The results show that CSD is the fastest algorithm and offers highest resolution among these three algorithms even though the pulse-wave may have gone through a significant change.

关键词： l1-LSD Sparse Deconvolution Cepstrum processing Wiener Filter

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Reconfigurable accelerator design platform for ultrasonic signal processing and imaging applications

Reconfigurable accelerator design platform for ultrasonic si...

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IEEE International Ultrasonics Symposium

作者： Paul Gal Jafar Saniie Embedded Computing and Signal Processing Research Laboratory Department of Electrical and Computer Engineering Illinois Institute of Technology Chicago U.S.A.

ISBN: (纸本)9781467398985

Ultrasonic testing and imaging systems have evolved from a basic single transducer system to arrays capable of 3-dimensional scans. These systems need to be flexible and also reconfigurable in order to acquire and process a vast amount of data. The system must also allow for a variety of parameters like the data acquisition rate, signal lengths and processing characteristics which need to be reconfigurable for adaptability to different applications. This study presents a reconfigurable hardware/software co-design system including specific hardware accelerators to acquire and perform ultrasonic signal processing efficiently. For this study, the architecture of the developed ultrasonic system is comprised of two different functional components. One component is specially designed to process the data while the other component gathers, compresses and transfers data which can later be restored and analyzed. For data transfer a simple and consequently efficient real-time operating system and Ethernet connective is developed. This is all implemented on the ZEDBoard Zynq SoC for maximum flexibility and performance. The data handling component is built with support for gathering, compressing, reconstructing, and transferring data to other platforms via Ethernet communication. The different variations of the designs allow the system designers the choice of applying the best solution for their specific applications.

关键词： Acoustics Discrete wavelet transforms Adders signal processing Field programmable gate arrays Real-time systems Image reconstruction Field programmable gate arrays discrete wavelet transform adders signal processing configurability real-time systems image reconstruction Acoustics ultrasonic signal ethernet communication hardware accelerator

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Convex cone volume analysis for finding endmembers in hyperspectral imagery

Convex cone volume analysis for finding endmembers in hypers...

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作者： Chang, Chein-I Xiong, Wei Chen, Shih-Yu Information and Technology College Dalian Maritime University Dalian China School of Physics and Optoelectronic Engineering Xidian University Xian China Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County BaltimoreMD21250 United States Department of Computer Science and Information Management Providence University Taichung Taiwan Department of Computer Science and Information Engineering National Yunlin University of Science and Technology Yunlin Taiwan

This paper presents a new approach, called convex cone volume analysis (CCVA), which can be considered as a partially constrained-abundance (abundance non-negativity constraint) technique to find endmembers. It can be shown that finding the maximal volume of a convex cone in the original data space is equivalent to finding the maximal volume of a simplex in a hyperplane. As a result, the CCVA can take advantage of many recently developed fast computational algorithms developed for N-FINDR to derive their counterparts for CCVA. © Copyright 2016 Inderscience Enterprises Ltd.

关键词： Spectroscopy

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A comparative study of singular spectrum analysis and empirical mode decomposition for ultrasonic NDE

A comparative study of singular spectrum analysis and empiri...

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IEEE International Ultrasonics Symposium

作者： Yufeng Lu Jafar Saniie Electrical and Computer Engineering Department Bradley University Peoria Illinois 61625 United States Embedded Computing and Signal Processing Laboratory Electrical and Computer Engineering Department Illinois Institute of Technology Chicago 60616 United States

ISBN: (纸本)9781467398985

In this investigation, a comparative study of two time-series analysis techniques, singular spectrum analysis (SSA) and empirical mode decomposition (EMD), is carried out for ultrasonic NDE applications. Unlike transform-based approaches, the SSA and EMD are fully driven in the time domain by the data itself. The SSA method captures the trend of signals via eigenvalues from a trajectory matrix. Whereas EMD searches intrinsic mode functions (IMF) via local maxima and minima, then the instantaneous frequency of IMFs is used to disclose the signal trends. Simulation shows that the trend tracking becomes problematic for defect assessment when signal trends become too complicated. As a remedy, a technique combing these two methods is proposed. Experimental and simulation results reveal the effectiveness of the collective effort from EMD and SSA. The study demonstrates that the data-driven nature is unique and attractive to characterize non-stationary ultrasonic signals where scattering, absorption and dispersion effects become dominant.

关键词： Acoustics Market research Ultrasonic imaging Eigenvalues and eigenfunctions Transforms Noise measurement Trajectory Ultrasonography Noise measurement Spectrum Analysis market research Eigenfunctions trajectory Transform Acoustics SSA CALR gene NDE1 gene Nondestructive Testing Defect assessment TIME-DOMAIN

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On the Ergodic Capacity of Multiple Antenna Cognitive Satellite Terrestrial Networks

On the Ergodic Capacity of Multiple Antenna Cognitive Satell...

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Ad-Hoc and Sensor Networks Symposium

作者： Kang An Min Lin Tao Liang Jian Ouyang Wei-Ping Zhu College of Communications Engineering PLA University of Science and Technology National Mobile Communications Research Laboratory Southeast University Nanjing Institute of Telecommunication Technology Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Department of Electrical and Computer Engineering Concordia University

ISBN: (纸本)9781479966653

The integration of cognitive radio (CR) into satellite networks is recognized as an effective strategy to enhance the efficiency of radio spectrum. This paper investigates the ergodic capacity of a multiple antenna cognitive satellite terrestrial network, where the secondary terrestrial system can coexist with the primary satellite system as long as the interference imposed from the secondary user (SU) to the primary user (PU) is below a predefined threshold. Specifically, the Meijer-G function based analytical expression for the ergodic capacity of the secondary network is derived, which not only provides an efficient means to evaluate the system performance but also characterize the impact of various channel parameters on the network. Finally, simulation results are provided to demonstrate the validity of the theoretical analysis.

关键词： Cognitive satellite terrestrial network Multiple antenna Ergodic capacity

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Coherent oscillations of driven rf SQUID metamaterials

arXiv

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arXiv 2017年

作者： Trepanier, Melissa Zhang, Daimeng Mukhanov, Oleg Koshelets, V.P. Jung, Philipp Butz, Susanne Ott, Edward Antonsen, Thomas M. Ustinov, Alexey V. Anlage, Steven M. Department of Physics CNAM University of Maryland College ParkMD20742 United States Department of Electrical and Computer Engineering University of Maryland College ParkMD20742 United States Hypres Inc. 175 Clearbrook Road ElmsfordNY10523 United States Laboratory of Superconducting Devices for Signal Detection and Processing Kotelnikov Institute of Radio Engineering and Electronics Moscow125009 Russia Physikalisches Institut Karlsruhe Institute of Technology Germany Russian Quantum Center National University of Science and Technology MISIS Moscow119049 Russia

Through experiments and numerical simulations we explore the behavior of rf SQUID (radio frequency superconducting quantum interference device) metamaterials, which show extreme tunability and nonlinearity. The emergent electromagnetic properties of this metamaterial are sensitive to the degree of coherent response of the driven interacting SQUIDs. Coherence suffers in the presence of disorder, which is experimentally found to be mainly due to a dc flux gradient. We demonstrate methods to recover the coherence, specifically by varying the coupling between the SQUID meta-atoms and increasing the temperature or the amplitude of the applied rf flux. Copyright © 2017, The Authors. All rights reserved.

关键词： Metamaterials

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Multiband Image Fusion Based on Spectral Unmixing

Multiband Image Fusion Based on Spectral Unmixing

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作者： Wei, Qi Bioucas-Dias, José Dobigeon, Nicolas Tourneret, Jean-Yves Chen, Marcus Godsill, Simon Signal Processing and Communications Laboratory Department of Engineering University of Cambridge CambridgeCB2 1PZ United Kingdom Instituto de Telecomunicacões Instituto Superior Técnico Universidade de Lisboa Lisboa1049-001 Portugal University of Toulouse Toulouse31071 France School of Computer Engineering Nanyang Technological University Singapore639798 Singapore DSO National Laboratories Singapore639798 Singapore

This paper presents a multiband image fusion algorithm based on unsupervised spectral unmixing for combining a high-spatial-low-spectral-resolution image and a low-spatial-high-spectral-resolution image. The widely used linear observation model (with additive Gaussian noise) is combined with the linear spectral mixture model to form the likelihoods of the observations. The nonnegativity and sum-to-one constraints resulting from the intrinsic physical properties of the abundances are introduced as prior information to regularize this ill-posed problem. The joint fusion and unmixing problem is then formulated as maximizing the joint posterior distribution with respect to the endmember signatures and abundance maps. This optimization problem is attacked with an alternating optimization strategy. The two resulting subproblems are convex and are solved efficiently using the alternating direction method of multipliers. Experiments are conducted for both synthetic and semi-real data. Simulation results show that the proposed unmixing-based fusion scheme improves both the abundance and endmember estimation compared with the state-of-the-art joint fusion and unmixing algorithms. © 2016 IEEE.

关键词： Image fusion

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GENERALIZED COPRIME SAMPLING OF TOEPLITZ MATRICES

GENERALIZED COPRIME SAMPLING OF TOEPLITZ MATRICES

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IEEE International Conference on Acoustics, Speech and signal processing

作者： Si Qin Yimin D. Zhang Moeness G. Amin Abdelhak Zoubir Center for Advanced Communications Villanova University Villanova PA 19085 USA Department of Electrical and Computer Engineering Temple University Philadelphia PA 19122 USA Signal Processing Group Technische Universit?t Darmstadt Darmstadt Germany

ISBN: (纸本)9781479999897

Increased demand on spectrum sensing over a broad frequency band requires a high sampling rate and thus leads to a prohibitive volume of data samples. In some applications, e.g., spectrum estimation, only the second-order statistics are required. In this case, we may use a reduced data sampling rate by exploiting a low-dimensional representation of the original high-dimensional signals. In particular, the covariance matrix can be reconstructed from compressed data by utilizing its specific structure, e.g., the Toeplitz property. In this paper, we propose a general coprime sampling concept that implements effective compression of Toeplitz covariance matrices. Given a fixed number of data samples, we examine different schemes on covariance matrix acquisition, based on segmented data sequences. The effectiveness of the proposed technique is verified using simulation results.

关键词： Compressive covariance sampling structured matrix coprime sampling overlapping segmented data Structured matrices Data sampling Covariance matrix variance covariance matrix Frequency bands Toeplitz matrices Data compression Spectrum Analysis dies matrices Toeplitz

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Improving secrecy performance via device-to-device jamming in cellular networks

Improving secrecy performance via device-to-device jamming i...

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International Conference on Wireless communications and signal processing (WCSP)

作者： Jian Ouyang Min Lin Wei-Ping Zhu Kang An Lei Wang Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Nanjing China Nanjing Institute of Telecommunication Technology Nanjing China Department of Electrical and Computer Engineering Concordia University Montreal QC Canada College of Communications Engineering PLA University of Science and Technology Nanjing China National Mobile Communications Research Laboratory Southeast University Nanjing China

ISBN: (纸本)9781509028610

In this paper, we study the secrecy performance of a cellular network, where a device-to-device (D2D) communication shares the spectral resources with a multi-antenna base station (BS). By assuming known the channel state information (CSI) of the legitimate user and using the maximal ratio transmission (MRT) at the BS, we first derive a closed-form expression of the ergodic secrecy capacity (ESC) for the wiretap channel as well as the ergodic capacity (EC) for the D2D link. Then, we present a simple yet efficient power allocation scheme to maximize the secrecy performance while satisfying the D2D transmission requirement. Finally, numerical results are given to demonstrate the merit of our study, concluding that the interference from the D2D communication can be exploited as a friendly jammer to enhance the security transmission in cellular networks.

关键词： Device-to-device communication Cellular networks Antennas Resource management Jamming Security Optimized production technology

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Ground Maneuvering Target Imaging and High-Order Motion Parameter Estimation Based on Second-Order Keystone and Generalized Hough-HAF Transform

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IEEE Transactions on Geoscience and Remote Sensing 2016年第99期PP卷

作者： Huang, Penghui Liao, Guisheng Yang, Zhiwei Xia, Xiang-Gen Ma, Jingtao Zheng, Jibin National Laboratory of Radar Signal Processing Xidian University Xian710071 China Department of Electrical and Computer Engineering University of Delaware NewarkDE19716 United States Shanghai Engineering Center for Microsatellites Shanghai201203 China

This paper proposes a new method to focus a ground moving target with complex motions and estimate its motion parameters in a synthetic aperture radar (SAR) system. In this method, the second-order Keystone transform is applied to correct the range curvature. Then, the Hough transform is applied to estimate the slope of the range walk trajectory, from which the target cross-track velocity is obtained. Finally, a generalized Hough-high-order ambiguity function (GHHAF) transform is applied to transform the target signal into a 2-D time-frequency plane and estimate its slope associated with the third-order Doppler parameter. Compared with the conventional SAR imaging methods using the second-order phase model, the proposed method can obtain better imaging quality since the third-order Doppler frequency migration is effectively eliminated. Both simulated and real data processing results are provided to validate the effectiveness of the proposed algorithm. © 2016 IEEE.

关键词： Parameter estimation

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