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Wavelet sparse representation based beam-forming for ultrasound imaging: Theory and simulation

Metallurgical and Mining Industry 2015年第9期7卷 777-781页

作者： Zhang, Qiong Shen, Minfen Li, Bin Cheng, Cheng College of Engineering Shantou University Shantou Guangdong China Guangdong Provincial Key Laboratory of Digital Signal and Image Processing Techniques Shantou Guangdong China Shantou Polytechnic Shantou Guangdong China Shantou Institute of Ultrasonic Instruments Co. Ltd. Shantou Guangdong China Dept of Intelligent Multimedia Technology Research Center Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences Chongqing China

In this paper, a wavelet sparse representation based beamforming is proposed to improve the resolution and contrast of plane wave emission ultrasound imaging. First, the received signals are described as the convolution of the target scatterers with the point spread function of the system. And then, the wavelet sparse representation model is deduced according to the fact that the target scatterers can be sparse represented in wavelet domain. The proposed algorithm was tested with simulated ultrasound data in plane wave emission. And the results demonstrated that the resolution was clearly improved and contrast ratio gains of 9.8 dB, 4.3 dB and 3.7 dB were obtained compared to delay-and-sum beamformer, minimum variance beamformer and phase coherence factor, respectively.

关键词： Optical transfer function

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A Performance Study of Spatial Modulation Systems Under Vehicle-to-Vehicle Channel Models

A Performance Study of Spatial Modulation Systems Under Vehi...

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IEEE Vehicular Technology Conference

作者： Yu Fu Cheng-Xiang Wang Raed Mesleh Xiang Cheng Harald Haas Yejun He Joint Research Institute for Signal and Image Processing Heriot-Watt University School of Information Science and Engineering Shandong University Electrical Engineering Department and SNCS Research Center University of Tabuk School of Electronics Engineering & Computer Science Peking University Joint Research Institute for Signal and Image Processing University of Edinburgh College of Information Engineering Shenzhen University

ISBN: (纸本)9781479944811

Spatial modulation (SM) is a relatively new multiple-input multiple-output (MIMO) technology that can provide high data rate with reasonable spectral efficiency. In this paper, the bit error rate (BER) performance of SM systems under vehicle-to-vehicle (V2V) channel models is investigated. The theoretical BER expression is given. The impact of some V2V channel model parameters on the underlying space-time correlation function (STCF) and the BER performance of SM systems are also studied. Simulation results indicate that modulation schemes, maximum Doppler frequency, the distance between the transmitter (Tx) and receiver (Rx), and antenna element spacings can affect the performance of SM systems.

关键词： Spatial modulation Vehicle-to-vehicle channel model Bit error rate Space-time correlation function

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Perceptually motivated temporal modeling of footsteps in a cross-environmental detection task

Perceptually motivated temporal modeling of footsteps in a c...

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2013 38th IEEE International Conference on Acoustics, Speech, and signal processing, ICASSP 2013

作者： Altaf, M. Umair Bin Butko, Taras Juang, Biing-Hwang Center for Signal and Image Processing School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA United States

ISBN: (纸本)9781479903566

Real world sounds are ubiquitous and form an important part of the edifice of our cognitive abilities. Their perception combines signatures from spectral and temporal domains, among others, yet traditionally their analysis is focused on the frame based spectral properties. We consider the problem of sound analysis from perceptual perspective and investigate the temporal properties of a 'footsteps' sound, which is a particularly challenging from the time-frequency analysis viewpoint. We identify the irregular repetition of the self similarity and the sense of duration as significant to its perceptual quality and extract features using the Teager-Kaiser energy operator. We build an acoustic event detection system for 'footsteps' which shows promising results for detection in cross-environmental conditions when compared with conventional approach. © 2013 IEEE.

关键词： acoustic analysis acoustic signal detection acoustics feature extraction time-frequency analysis

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Person identification using biometric markers from footsteps sound

Person identification using biometric markers from footsteps...

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14th Annual Conference of the International Speech Communication Association, INTERSPEECH 2013

Human identification using unobtrusive methods is a challenging problem that has many applications in surveillance tasks. In this work we propose a set of biometric features extracted from a footstep audio signal that can be used to identify a person. Instead of using short-time spectral domain, Teager-Kaiser energy operator is employed to transform a time-domain signal into a representational domain where the intrinsic properties of the walking style of each individual become apparent. We show that these features are biometrically significant as they are physical correlates of human gait. The experimental results obtained using a recently recorded publicly available database show prominent results in a human identification task. Copyright © 2013 ISCA.

关键词： Biometrics

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PERCEPTUALLY MOTIVATED TEMPORAL MODELING OF FOOTSTEPS IN A CROSS-ENVIRONMENTAL DETECTION TASK

PERCEPTUALLY MOTIVATED TEMPORAL MODELING OF FOOTSTEPS IN A C...

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IEEE International Conference on Acoustics, Speech, and signal processing

作者： M. Umair Bin Altaf Taras Butko Biing-Hwang (Fred) Juang Center for Signal and Image Processing School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta Georgia.

ISBN: (纸本)9781479903573

Real world sounds are ubiquitous and form an important part of the edifice of our cognitive abilities. Their perception combines signatures from spectral and temporal domains, among others, yet traditionally their analysis is focused on the frame based spectral properties. We consider the problem of sound analysis from perceptual perspective and investigate the temporal properties of a "footsteps" sound, which is a particularly challenging from the time-frequency analysis viewpoint. We identify the irregular repetition of the self similarity and the sense of duration as significant to its perceptual quality and extract features using the Teager-Kaiser energy operator. We build an acoustic event detection system for "footsteps" which shows promising results for detection in cross-environmental conditions when compared with conventional approach.

关键词： Temporal modeling HMM Teager-Kaiser operator Acoustic event detection Hidden Markov models Event detection SOUND KCNK3 gene edifices time characteristic Modeling Vibration Hearing signatures

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INTRA-RETINAL LAYER SEGMENTATION OF OPTICAL COHERENCE TOMOGRAPHY USING DIFFUSION MAP

INTRA-RETINAL LAYER SEGMENTATION OF OPTICAL COHERENCE TOMOGR...

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IEEE International Conference on Acoustics, Speech, and signal processing

作者： Raheleh Kafieh Hossein Rabbani Michael Abramoff Milan Sonka Biomedical Engineering Dept. Medical Image & Signal Processing Research Center Isfahan Univ. of Medical Sciences Isfahan Iran The Iowa Institute for Biomedical Imaging The University of Iowa

ISBN: (纸本)9781479903573

Optical coherence tomography (OCT) is known to be one of the powerful and noninvasive methods in retinal imaging. OCT uses retroreflected light to provide micron-resolution, cross-sectional scans of biological tissues. In contrast to OCT technology development, which has been a field of active research since 1991, OCT image segmentation has only been fully explored during the last decade. In this paper, we introduce a fast segmentation method based on a new kind of spectral graph theory named diffusion maps. The research is performed on spectral domain OCT images depicting normal macular appearance. In contrast to our recent methods of graph based OCT image segmentation, the presented approach does not require edge-based image information and rather relies on regional image texture. Consequently, the proposed method demonstrates robustness in situations of low image contrast or poor layer-to-layer image gradients. This method is tested on thirteen 3D macular SD-OCT images obtained from eyes without pathologies with Topcon 3D OCT-1000 imaging system (with a size of 650 × 512 × 128 voxels and a voxel resolution of 4.81 × 13.67 × 24.41 μm~3). The mean unsigned and signed border positioning errors (mean ± SD) was 8.52±3.13 and -4.61±3.35 micrometers, respectively. The average computation time of the proposed algorithms (implemented with MATLAB) was 12 seconds per 2D slice.

关键词： optical coherence tomography Graph theory diffusion image texture image information TISSUES (BIOLOGY) image CONTRAST image segmentation MATLAB computational time pathology

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VESSEL SEGMENTATION IN imageS OF OPTICAL COHERENCE TOMOGRAPHY USING SHADOW INFORMATION AND THICKENING OF RETINAL NERVE FIBER LAYER

VESSEL SEGMENTATION IN IMAGES OF OPTICAL COHERENCE TOMOGRAPH...

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IEEE International Conference on Acoustics, Speech, and signal processing

作者： Raheleh Kafieh Hajar Danesh Hossein Rabbani Michael Abramoff Milan Sonka Biomedical Engineering Dept. Medical Image & Signal Processing Research Center Isfahan Univ. of Medical Sciences Isfahan Iran The Iowa Institute for Biomedical Imaging The University of Iowa

ISBN: (纸本)9781479903573

The correct segmentation of blood vessels in optical coherence tomography (OCT) images is an important requirement for better diagnosis of many retinal diseases. Although OCT blood vessel segmentation is often performed by applying vessel detection methods on 2D projection of OCT datasets, some papers investigate the vessel segmentation on OCT slices. The presence of shadows in outer retinal layers is established as the main factor for vessel localization;however, the shadow information fails to localize many important blood vessels. The proposed method is based on anatomical changes of Retinal Nerve Fiber Layer (RNFL) in presence of vessels. In this paper we find the thickening of RNFL by applying a layer segmentation algorithm on OCT slices and combine this information with shadow localization. Furthermore, a vessel detection method based on curvelet transform is also applied on 2D projection of OCTs to be added to localized vessels from OCTs. The results show that combination of vessel detection on 2D projection with vessel localization on OCTs can improve the accuracy up to 0.96 which is promisingly higher than older methods.

关键词： Vessel segmentation OCT image Retinal Nerve Fiber Layer optical coherence tomography Blood Vessels Thickening pressure vessels images 3-glucosaminoglycan sulfate shadows inspection methods segmentation Segmentation Fiber

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Energy Evaluation of Spatial Modulation at a Multi-Antenna Base Station

Energy Evaluation of Spatial Modulation at a Multi-Antenna B...

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IEEE Vehicular Technology Conference

作者： Athanasios Stavridis Sinan Sinanovi? Marco Di Renzo Harald Haas Institute for Digital Communications Joint Research Institute for Signal and Image Processing School of Engineering The University of Edinburgh Edinburgh UK School of Engineering and Built Environment Glasgow Caledonian University Glasgow UK Laboratory of Signals and Systems (L2S) French National Center for Scientific Research (CNRS) école Supérieure d'électricité (SUPéLEC) University ofParis-Sud XI (UPS) Paris France

ISBN: (纸本)9781467361866

In this paper, we aim to study the Energy Efficiency (EE) of Spatial Modulation (SM) at different Base Stations (BSs) taking into account the total power consumption. Compared to conventional Multiple-Input Multiple-Output (MIMO) schemes, SM benefits from a single Radio Frequency (RF) chain which results in decreased power supply (W), higher EE (Mbits/J), and reduced complexity. Using the fundamental limits of Shannon capacity, we show that SM achieves a range of average data rates with only a fraction, which can be as low as 24% for four transmit antennas, of the total power supply of conventional MIMO. In addition, we demonstrate that the EE of the studied schemes is maximized for a certain average data rate and that SM achieves the highest EE among them. Finally, we note that a BS employing SM can be up to 67% more energy efficient compared to a BS under a conventional MIMO transmission scheme, for four transmit antennas.

关键词： EE SM BSs

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A non-stationary geometry-based stochastic model for MIMO high-speed train channels

A non-stationary geometry-based stochastic model for MIMO hi...

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International Conference on ITS Telecommunications (ITST)

作者： Ammar Ghazal Cheng-Xiang Wang Harald Haas Mark Beach Raed Mesleh Dongfeng Yuan Xiaohu Ge Mohamed Khaled Chahine Joint Research Institute for Signal and Image Processing Heriot-Watt University Edinburgh UK School of Information Science and Engineering Shandong University Jinan China Joint Research Institute for Signal and Image Processing University of Edinburgh Edinburgh UK Department of Electrical & Electronic Engineering University of Bristol Bristol UK Sensor Networks and Cellular Systems (SNCS) Research Center University of Tabuk Tabuk Saudi Arabia Department of Electronics and Information Engineering Huazhong University of Science and Technology Wuhan Hubei China Faculty of Mechanical and Electrical Engineering Damascus University Syria

In this paper, a non-stationary wideband geometry-based stochastic model (GBSM) is proposed for multiple-input multiple-output (MIMO) high-speed train (HST) channels. The proposed model employs multiple confocal ellipses model, where the received signal is a superposition of the line-of-sight (LoS) and single-bounced rays. Because of the time-varying feature of angles of arrival (AoAs), angles of departure (AoDs), and LoS angle, the proposed GBSM has the ability to investigate the non-stationarity of HST environment caused by the high speed movement of the receiver. From the proposed model, the local spatial cross-correlation function (CCF) and the local temporal autocorrelation (ACF) are derived for different taps. Numerical results and analysis show that the proposed channel model is capable of characterizing the time-variant HST wireless channel.

关键词： Channel models MIMO Wireless communication Educational institutions Correlation Antennas Rail transportation

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Performance analysis of indoor OFDM optical wireless communication systems

Performance analysis of indoor OFDM optical wireless communi...

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IEEE Conference on Wireless Communications and Networking

作者： Raed Mesleh Hany Elgala Harald Haas Electrical Engineering Department and Sensor Networks and Cellular Systems (SNCS) research Center University of Tabuk Tabuk Saudi Arabia Jacobs University Bremen Bremen Germany Institute for Digital Communications Joint Research Institute for Signal and Image Processing University of Edinburgh Edinburgh UK

In this paper, the performance of indoor OFDM (orthogonal frequency division multiplexing) optical wireless (OW) communication systems in the presence of LED (light emitting diode) clipping distortions is analyzed. Two indoor OW OFDM techniques are considered. An ACO-OFDM (asymmetrically clipped optical OFDM) system produces half-wave symmetry time signal at the output of the OFDM modulator by special assignment of subcarriers. Therefore, bipolar-unipolar conversion is achieved by clipping the signal at the zero level at the expense of data rate reduction. The second technique, called DCO-OFDM (DC-biased optical OFDM), assigns data to all possible subcarriers to increase the data rate. However, half-wave symmetry signals cannot be achieved and a DC bias is needed to convert the bipolar signal to a unipolar signal before modulating the LED intensity. The performance of these systems, in terms of average electrical OFDM signal power versus bit-error-ratio (BER), DC power consumption, and transmitted optical power in the presence of additive white Gaussian noise (AWGN) channel and considering a practical LED model, are studied. Analytical results are validated through Monte Carlo simulation results and the results demonstrate close match. The results clearly highlight that LED clipping has significant impact on the performance of these systems and system design should consider optimizing the OFDM signal power, DC bias point, and LED dynamic range.

关键词： OFDM Light emitting diodes Optical distortion Optical sensors Optical modulation Noise

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