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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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Facial Expression Recognition Using Diffeomorphic image Registration Framework

Facial Expression Recognition Using Diffeomorphic Image Regi...

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作者： Papiez, Bartlomiej W. Matuszewski, Bogdan J. Shark, Lik-Kwan Quan, Wei Applied Digital Signal and Image Processing Research Centre University of Central Lancashire PR1 2HE Preston United Kingdom

ISBN: (纸本)9781461450757

This paper presents a new method for facial expression modelling and recognition based on diffeomorphic image registration parameterised via stationary velocity fields in the log-Euclidean framework. The validation and comparison are done using different statistical shape models (SSM) built using the Point Distribution Model (PDM), velocity fields and deformation fields. The obtained results show that the facial expression representation based on stationary velocity fields can be successfully utilised in facial expression recognition, and this parameterisation produces a higher recognition rate than the facial expression representation based on deformation fields. © Springer Science+Business Media New York 2013.

关键词： Velocity

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Non-Rigid Structure from Motion with Diffusion Maps Prior

Non-Rigid Structure from Motion with Diffusion Maps Prior

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IEEE Conference on Computer Vision and Pattern Recognition

作者： Lili Tao Bogdan J. Matuszewski Applied Digital Signal and Image Processing Research Centre University of Central Lancashire

ISBN: (纸本)9781467364102

In this paper, a novel approach based on a non-linear manifold learning technique is proposed to recover 3D non-rigid structures from 2D image sequences captured by a single camera. Most of the existing approaches assume that 3D shapes can be accurately modelled in a linear subspace. These techniques perform well when the deformations are relatively small or simple, but fail when more complex deformations need to be recovered. The non-linear deformations are often observed in highly flexible objects for which the use of the linear model is impractical. A specific type of shape variations might be governed by only a small number of parameters, therefore can be well-represented in a low dimensional manifold. We learn a nonlinear shape prior using diffusion maps method. The key contribution in this paper is the introduction of the shape prior that constrain the reconstructed shapes to lie in the learned manifold. The proposed methodology has been validated quantitatively and qualitatively on 2D points sequences projected from the 3D motion capture data and real 2D video sequences. The comparisons of the proposed manifold based method against several state-of-the-art techniques are shown on different types of deformable objects.

关键词： Shape Manifolds Three-dimensional displays Trajectory Training Cameras image reconstruction

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Inter-view Reference Frame Selection in Multi-view Video Coding

Inter-view Reference Frame Selection in Multi-view Video Cod...

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Data Compression Conference (DCC)

作者： Guang Y. Zhang Abdelrahman Abdelazim Stephen James Mein Martin Roy Varley Djamel Ait-Boudaoud Applied Digital Signal and Image Processing Research Centre University of Central Lancashire UK University of Portsmouth UK

ISBN: (纸本)9781467360371

Summary form only given. Multiple video cameras are used to capture the same scene simultaneously to acquire the multiview view coding data, obviously, over-large data will affect the coding efficiency. Due to the video data is acquired from the same scene, the inter-view similarities between adjacent camera views are exploited for efficient compression. Generally, the same objects with different viewpoints are shown on adjacent views. On the other hand, containing objects at different depth planes, and therefore perfect correlation over the entire image area will never occur. Additionally, the scene complexity and the differences in brightness and color between the video of the individual cameras will also affect the current block to find its best match in the inter-view reference picture. Consequently, the temporal-view reference picture is referred more frequently. In order to gain the compression efficiency, it is a core part to disable the unnecessary inter-view reference. The idea of this paper is to exploit the phase correlation to estimate the dependencies between the inter-view reference and the current picture. If the two frames with low correlation, the inter-view reference frame will be disabled. In addition, this approach works only on non-anchor pictures. Experimental results show that the proposed algorithm can save 16% computational complexity on average, with negligible loss of quality and bit rate. The phase correlation process only takes up 0.1% of the whole process.

关键词： Correlation Educational institutions Motion estimation Video coding PSNR Data compression image processing

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Two-Step Hybrid Self-Localization Using Unsynchronized Low-Complexity Anchors

Two-Step Hybrid Self-Localization Using Unsynchronized Low-C...

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International Conference on Localization and GNSS

作者： Yue Wang Michael Wiemeler Feng Zheng Weiming Xiong Thomas Kaiser Institute of Digital Signal Processing University of Duisburg-Essen Center for Space Science and Applied Research Chinese Academy of Sciences

ISBN: (纸本)9781479904846

Self-localization using unsynchronized low-complexity anchors has a number of attractive features. Traditional self-localization techniques are not suitable to this scenario or have their applicability limitations. In this paper, a two-step hybrid self-localization technique using unsynchronized low-complexity anchors is proposed, which can achieve two-dimensional (2-D) instantaneous localization for both mobile and fixed agents and eliminate the need for heading information of the agents. In the first step, an initial location estimate is obtained utilizing range information based on received-signal-strength (RSS) measurements. In the second step, differential angle-of-arrival (AOA) measurements are converted to range measurements with the aid of the first step location estimate. Finally, a two-step hybrid localization algorithm is obtained using all the measurements in the first step and the second step. Simulation results show that the two-step hybrid self-localization technique has relatively high accuracy even in the scenarios with large RSS-based ranging variances and medium AOA measurement variances.

关键词： Angle-of-arrival (AOA) Hybrid Received-signal-strength (RSS) Self-localization 60 GHz Ultra-wideband (UWB) Unsynchronized low-complexity anchors

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Reference Selection for Hybrid TOA/RSS Linear Least Squares Localization

Reference Selection for Hybrid TOA/RSS Linear Least Squares ...

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IEEE Conference on Vehicular Technology (VTC)

作者： Yue Wang Feng Zheng Michael Wiemeler Weiming Xiong Thomas Kaiser Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China Institute of Digital Signal Processing University of Duisburg-Essen Duisburg Germany

Linear least squares (LLS) estimation is a suboptimum but low-complexity localization method based on measurements of location-related parameters. It has been proved that selection of the reference anchor influences the LLS localization accuracy. In addition, hybridization of different types of measurements can fix the deficiencies of one type of measurements. In this paper, we proposed a new reference selection criterion for the hybrid TOA/RSS LLS localization technique (called H-LLSRS), which considers both measured ranges and the information about their coarse variances. Moreover, we consider a general scenario that variances of range measurements are different, and derive a weighted LLS (WLLS) estimator for hybrid TOA/RSS localization according to the information about the accurate ranging variances and the correlations among the observations. Simulation results show that if the RSS-based ranging variances are considerably larger than the TOA-based ranging variances, the H-LLS-RS localization technique yields better accuracy than the conventional LLS localization techniques. Furthermore, reference selection has no effect on the accuracy of WLLS localization technique.

关键词： Distance measurement Accuracy Maximum likelihood estimation Simulation signal to noise ratio Vectors

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较小样本动态声发射信号多元统计分析技术

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振动．测试与诊断 2013年第2期33卷 199-203,335页

作者：陈宏志芦永明王丽娜 Lik-Kwan Shark John Goodacre 冶金自动化研究设计院混合流程工业自动化系统与装备技术国家重点实验室北京100071 Applied Digital Signal and Image Processing Research Centre University of Central Lancashire PrestonUnited KingdomPR12HE School of Health and Medicine Lancaster University LancasterUnited KingdomLA14YD

利用多传感信息集成系统,以两组平均年龄对应的受试对象往复运动过程中获取的动态声发射信号和角度信号为对象,研究了适用于较小样本的动态声发射信号多元统计分析技术。通过同步记录的角度信号,将往复运动分解为若干个独立运动周期和... 详细信息

利用多传感信息集成系统,以两组平均年龄对应的受试对象往复运动过程中获取的动态声发射信号和角度信号为对象,研究了适用于较小样本的动态声发射信号多元统计分析技术。通过同步记录的角度信号,将往复运动分解为若干个独立运动周期和运动过程;利用累计概率分布,选取具备较显著差异的特征;结合多元统计技术,减小数据量,建立动态声发射信号的可视化模型,证实了使用较小样本声发射信号实现膝盖骨关节诊断的可行性。

关键词：较小样本动态声发射多元统计骨关节炎

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Facial expression recognition using log-euclidean statistical shape models

Facial expression recognition using log-euclidean statistica...

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1st International Conference on Pattern Recognition Applications and Methods, ICPRAM 2012

ISBN: (纸本)9789898425980

This paper presents a new method for facial expression modelling and recognition based on diffeomorphic image registration parameterised via stationary velocity fields in Log-Euclidean framework. The validation and comparison are done using different statistical shape models (SSM) built using the Point Distribution Model (PDM), velocity fields, and deformation fields. The obtained results show that the facial expression representation based on stationary velocity field can be successfully utilised in facial expression recognition, and this parameterisation produces higher recognition rate than the facial expression representation based on deformation fields.

关键词： Velocity

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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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NON-RIGID STRUCTURE FROM MOTION WITH INCREMENTAL SHAPE PRIOR

NON-RIGID STRUCTURE FROM MOTION WITH INCREMENTAL SHAPE PRIOR

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IEEE International Conference on image processing

作者： Lili Tao Bogdan J. Matuszewski Stephen J. Mein Applied Digital Signal and Image Processing Research Centre University of Central Lancashire Preston UK

Most existing approaches to the non-rigid structure from motion problem use batch type algorithms with all the data collected before 3D shape reconstruction takes place. Such a methodology is not suitable for real-time applications. Concurrent on-line estimation of the camera position and 3D structure, based only on the measurements up to that moment is much more a challenging problem. In this paper, a novel approach is proposed for recursive recovery of non-rigid structures from image sequences captured by an orthographic camera. The main novelty in the proposed method is an adaptive algorithm for construction of shape constraints imposing stability on the on-line reconstructed shapes. The proposed, adaptively learned constraints have two aspects, consisting of constraints imposed on the basic shapes, the basic "building blocks" from which shapes are reconstructed, as well as constraints imposed on the mixing coefficients in a form of their probability distribution. The constraints are updated when the current model inadequately represents new shapes. This is achieved by means of Incremental Principal Component Analysis (IPCA). Results of the proposed method are shown on synthetic and real data of articulated face.

关键词： Shape image reconstruction Principal component analysis Cameras Face Vectors Optimization

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