检索结果-内蒙古大学图书馆

An Improved Method for Phase Extraction Based on Gray Extremum

Procedia engineering 2012年 29卷 2355-2359页

作者： Xiu Qin Xiaoping Lou Naiguang Lv Peng Sun School of Photoelectronic Information & Communication Engineering Beijing Information Science & Technology University Beijing 100192 China Beijing Key Laboratory on Measurement and Control of Mechanical and Electrical System Beijing Information Science & Technology University Beijing 100192 China

Surface deformation of an object can be measured by digital shearography through non-contact measurement with a simple device. It is always difficult to remove the noise of the speckle interference. Consequently extracting phase from a single fringe pattern without carrier-frequency is complex. Based on gray extremum, an improved method for phase extraction is proposed by using the improved image binarization algorithm in this paper. Through comparing the average value of eight neighbourhood points around each pixel with threshold value, the quality of binary image can be improved, and then the skeleton line can be extracted. Finally a smooth extremum image can be obtained. Experimental results show that the proposed method is simple, convenient and reliable.

关键词： shearography phase extraction gray extremum method binarization skeleton

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Polar-radius-invariant-moment based on key-points for hand gesture shape recognition

Journal of Software

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Journal of Software 2012年第1期7卷 88-94页

作者： Zhao, Fu Ging Li, Xin Ying Zhang, Qiu Yu Jonrinaldi School of Computer and Communication Lanzhou University of Technology Lanzhou China Key Laboratory of Gansu Advanced Control for Industrial Process Lanzhou China School of Engineering Computer Science and Mathematics University of Exeter EX4 4QF United Kingdom

For the whole matching cannot handle partial occlusion and lack of specificity, a new method using Polar- Radius-Invariant-Moment, which is based on Key-Points to extract features for target's shape recognition, is presented in this paper. Firstly, key-points of the hand shape are extracted through discrete curve evolution method. Secondly, Polar-Radius-Invariant-Moment based on Key- Points is used to describe the characteristics of the gesture shape. Finally, Euclidean distance is utilized in gesture recognition to verify the validity of this method. Hand objects are selected as the test case to testify the performance of the method. Simulation results prove that this method has a better classification character than that of obtained by the Polar-Radius-Invariant-Moment with recognizing the object shape rapidly and accurately, and that it also can keep highly stable even if the object contour was ill-segmented or noisy. © 2012 ACADEMY PUBLISHER.

关键词： Gesture recognition

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Repetitive process based iterative learning control for a two motors system

Repetitive process based iterative learning control for a tw...

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IEEE Conference on control technology and Applications (CCTA)

作者： Lukasz Hladowski Krzysztof Galkowski Eric Rogers Lan Zhou Yong He Anton Kummert Institute of Control and Computation Engineering University of Zielona Gora Poland Electronics and Computer Science University of Southampton Southampton UK School of Information and Electrical Engineering Hunan University of Science and Technology Xiangtan China School of Information Science and Engineering Central South University Changsha China Electrical Information and Media Engineering Communication Theory University of Wuppertal Germany

This paper uses a 2D systems setting, based on the control theory for repetitive processes, to design an iterative learning control law with particular emphasis on the commonly encountered problem of maintaining a specified rotational speed of shaft where disturbances introduce irregularities in the speed achieved. The two motors system is a model for this problem and is used as the basis for a simulation study of the performance of the final design.

关键词： Stability analysis Asymptotic stability State-space methods Convergence Vectors DC motors Process control

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Quantum filtering for systems driven by fields in single-photon states or superposition of coherent states

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Physical Review A 2012年第4期86卷 043819-043819页

作者： John E. Gough Matthew R. James Hendra I. Nurdin Joshua Combes Institute of Mathematics and Physics Aberystwyth University SY23 3BZ Wales United Kingdom ARC Centre for Quantum Computation and Communication Technology Research School of Engineering Australian National University Canberra ACT 0200 Australia Research School of Engineering The Australian National University Canberra ACT 0200 Australia Center for Quantum Information and Control University of New Mexico Albuquerque NM 87131-0001 USA

We derive the stochastic master equations, that is to say, quantum filters, and master equations for an arbitrary quantum system probed by a continuous-mode bosonic input field in two types of nonclassical states. Specifically, we consider the cases where the state of the input field is a superposition or combination of (1) a continuous-mode, single-photon wave packet and vacuum, and (2) any continuous-mode coherent states.

关键词： QUANTUM theory PHOTONS SUPERPOSITION principle (Physics) COHERENT states STOCHASTIC processes COMBINATIONS (Mathematics)

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Research of the scheduling method for fieldbus network real-time information

Research of the scheduling method for fieldbus network real-...

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6th International Forum on Strategic technology, IFOST 2011

作者： Zhang, Yuping Li, Chen Higher Educational Key Laboratory for Measuring and Control Technology College of Measure-Control Tech.and Communication Engineer Harbin University of Science and Technology Harbin China School of Electrical Engineering and Automation Harbin Institute of Technology Harbin China

ISBN: (纸本)9781457703966

The real time property of fieldbus network is very important to industrial control system, and the scheduling method of real-time information is an important factor that influences the real time property of fieldbus network. According to industrial real-time applications, a node produces a variety of information which have different requirements for real-time characteristics, the mixed service strategies scheduling method has been presented. This method makes the information scheduling process have the real-time property and without losing its flexibility. The results of simulation show that, compared with the traditional way of using a single service rule, the mixed service rule makes the transmission delay time of real-time information reduced by 50.00%53.75%. © 2011 IEEE.

关键词： Medium access control

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Cooperative MIMO Channel Modeling and Multi-Link Spatial Correlation Properties

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IEEE Journal on Selected Areas in communications 2012年第2期30卷 388-396页

作者： Xiang Cheng Cheng-Xiang Wang Haiming Wang Xiqi Gao Xiao-Hu You Dongfeng Yuan Bo Ai Qiang Huo Ling-Yang Song Bing-Li Jiao School of Electronics and Computer Science Peking University Beijing China Key Laboratory of Wireless Sensor Network & Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences China State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University China Joint Research Institute for Signal and Image Processing School of Engineering & Physical Sciences Heriot-Watt University Edinburgh UK School of Information Science and Engineering South East University Najing China School of Information Science and Engineering Shandong University Jinan China State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China

In this paper, a novel unified channel model framework is proposed for cooperative multiple-input multiple-output (MIMO) wireless channels. The proposed model framework is generic and adaptable to multiple cooperative MIMO scenarios by simply adjusting key model parameters. Based on the proposed model framework and using a typical cooperative MIMO communication environment as an example, we derive a novel geometry-based stochastic model (GBSM) applicable to multiple wireless propagation scenarios. The proposed GBSM is the first cooperative MIMO channel model that has the ability to investigate the impact of the local scattering density (LSD) on channel characteristics. From the derived GBSM, the corresponding multi-link spatial correlation functions are derived and numerically analyzed in detail.

关键词： MIMO Correlation Channel models Scattering Educational institutions Fading Adaptation models

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The influence of PROFIBUS message block time on transmission delay time property

The influence of PROFIBUS message block time on transmission...

引用

6th International Forum on Strategic technology, IFOST 2011

ISBN: (纸本)9781457703966

The real time property of fieldbus is very important to industrial control system. The transmission time delay is an important factor that influences the real time property of fieldbus. Starting from the medium access control mechanism of PROFIBUS, the PROFIBUS simplified transmission time delay formulas were given, and one of the important factors that influence message transmission time delay message block time, has been deeply analyzed. According to the relation of the address of the node which tries to send message with the node which owns the token, PROFIBUS message block time mathematical model was proposed, and the correctness of the mathematical model has been validated by the simulation. The conclusion of this paper will provide the theoretic reference basis for the further study on the real time property of PROFIBUS. © 2011 IEEE.

关键词： Medium access control

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A new method for realizing LOG filter in image edge detection

A new method for realizing LOG filter in image edge detectio...

引用

6th International Forum on Strategic technology, IFOST 2011

作者： Xu, Jingbo Liu, Bo Lin, Haijun Li, Jianxin College of Measure-control Technology and Communication Engineering Harbin University of Science and Technology Harbin 150080 China Higher Educational Key Laboratory for Measuring and Control Technology Instrumentations of Heilongjiang Province Harbin 150080 China

ISBN: (纸本)9781457703966

LOG filter for image edge detection consists of Gaussian filter and Laplace operator. Based on the central limit theorem and the separating characteristic of two dimensional Gaussian filter, Gaussian approximation filter is constructed. The digital filtering algorithm for Gaussian approximation filter is concluded through the bilinear transformation method and zero phase shift filtering technology. The algorithm combined with the Laplace operator has been successfully applied in the implementation of LOG filtering for edge detection. Applying Gaussian approximation filter in LOG filtering is helpful for multi-scale LOG filtering because only one parameter in the algorithm needs to be changed. This method is more convenient than the template method in which the coefficients of the whole mask of LOG filter with different scale need to be refreshed. This is a new implementation for LOG filter. © 2011 IEEE.

关键词： Laplace transforms

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Approximation implementation approach for Gaussian filtering in roundness measurement

Approximation implementation approach for Gaussian filtering...

引用

6th International Forum on Strategic technology, IFOST 2011

ISBN: (纸本)9781457703966

Gaussian filter acts as the filter for roundness signal processing and a new implementation approach for Gaussian filter is presented. Based on the theory of B-spline function, the variational principle with the tension condition and the convolution characteristic of Gaussian filter with small scale, the approximation filter of Gaussian filter is concluded, which has the amplitude characteristic deviation from Gaussian filter less than 1% and the zero-phase-shift characteristic. The algorithm for the approximation filter consists of the zero-phase-shift filtering and the weighing filtering which loop two times. The algorithm is both simply in its structure and high in its filtering efficiency. The method of cycle continuation solves the edge effects of digital filtering based on the periodicity of the roundness measurement signal. The approximation filter is also efficient and accurate for the implementation of Gaussian filter in the application of roundness measurement. © 2011 IEEE.

关键词： Interpolation

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Analysis of secondary throughput and optimization in cooperative spectrum sensing

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The Journal of China Universities of Posts and Telecommunications 2011年第4期18卷 39-44页

作者： LI Mei-ling YUAN Chao-wei LI Lin YANG Rui-zhe School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China School of Electronics and Information Engineering Taiyuan University of Science and Technology Taiyuan 030024 China College of Electronic Information and Control Engineering Beijing University of Technology Beijing 100022 China

In cooperative spectrum sensing, more secondary user makes more opportunity for detecting the vacant spectrums, which resulting the spectrum utilization improved, however much bandwidth would be occupied for sending the local observation results, inducing the reduced secondary throughput. In this paper, an adaptive algorithm for selecting detection threshold was proposed, where the maximized secondary throughput can always be achieved while assuring sufficient protection to primary user, regardless of the number of sensing users in cognitive radio networks. Theoretical analysis and simulation results validate the proposed scheme.

关键词： cooperative spectrum sensing secondary throughput spectrum utilization primary user secondary user detection threshold

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