Multi-image gradient-based algorithms for motion measurement using wavelet transform

A multi-image wavelet transform motion estimation algorithm based on gradient methods is presented by using the characteristic of wavelet transform. In this algorithm, the accuracy can be improved greatly using data in many images to measure motions between two images. In combination with the reliability measure for constraints function, the reliable data constraints of the images were decomposed with multi-level simultaneous wavelet transform rather than the traditional coarse-to-fine approach. Compared with conventional methods, this motion measurement algorithm based on multi-level simultaneous wavelet transform avoids propagating errors between the decomposed levels. Experimental simulations show that the implementation of this algorithm is simple, and the measurement accuracy is improved. __________ Translated from Journal of South China University of Technology (Natural Science Edition), 2007, 35(1): 39–43 [译自: 华南理工大学学报(自然科学版)]     

基于Motorola VP Oncore接收机的新型GPS共视时间传递系统

本文设计了基于Motorola VP Oncom接收机的新型GPS共视时间传递系统,用高分辨时间间隔计数器测量本地原子钟和GPS接收机输出秒信号的时差,通过读取导航电文得到GPST和指定卫星的时差,于是得到本地原子钟与指定星钟的时差,实现GPS共视法单站测量。为确保系统严格共视,使用多线程和同步监测机制设计了可靠的同步控制策略,两套系统的超短基线单通道共视比对结果表明,系统性能稳定,比对精度(用原始共视数据的均方根表示)不大于4．9m,该系统可应用于SDH通信网时间同步、交换机时间同步等高精度定时领域。     

Parallel VLSI design for the fast 3-D DWT core algorithm

By studying the core algorithm of a three-dimensional discrete wavelet transform (3-D DWT) in depth, this paper divides it into three one-dimensional discrete wavelet transforms (1-D DWTs). Based on the implementation of a 3-D DWT software, a parallel architecture design of a very large-scale integration (VLSI) is produced. It needs three dual-port random-access memory (RAM) to store the temporary results and transpose the matrix, then builds up a pipeline model composed of the three 1-D DWTs. In the design, the finite state machine (FSM) is used well to control the flow. Compared with the serial mode, the experimental results of the post synthesized simulation show that the design method is correct and effective. It can increase the processing speed by about 66%, work at 59 MHz, and meet the real-time needs of the video encoder. Translated from Transactions of Beijing Institute of Technology, 2006, 26(3): 211–215 [译自: 北京理工大学学报]     

Compression algorithm for electrocardiograms based on sparse decomposition

Sparse decomposition is a new theory in signal processing, with the advantage in that the base (dictionary) used in this theory is over-complete, and can reflect the nature of a signal. Thus, the sparse decomposition of signal can obtain sparse representation, which is very important in data compression. The algorithm of compression based on sparse decomposition is investigated. By training on and learning electrocardiogram (ECG) data in the MITBIH Arrhythmia Database, we constructed an overcomplete dictionary of ECGs. Since the atoms in this dictionary are in accord with the character of ECGs, it is possible that an extensive ECG datum is reconstructed by a few nonzero coefficients and atoms. The proposed compression algorithm can adjust compression ratio according to practical request, and the distortion is low (when the compression ratio is 20:1, the standard error is 5.11%). The experiments prove the feasibility of the proposed compression algorithm. __________ Translated from Chinese Journal of Biomedical Engineering, 2008, 27 (1): 13–17 [译自: 中国生物医学工程学报]     

Absorption of electromagnetic wave by inhomogeneous, unmagnetized plasma

In this article, a novel and normalized Z-transform finite-difference time-domain (ZTFDTD) method is presented. This method uses a more general form of Maxwell’s equations using the E, H, D fields. The iterative model of D-E-H-D can be obtained by using the Z-transform resulted frequency-dependent formula between D and E. The advantages of the ZTFDTD consist in that the discrete equations are simple, the results are precise, easy to program and capable of dealing with the key technologies of finite-difference time-domain (FDTD), such as absorbing boundary conditions (uniaxial anisotropic perfectly matched layer, UPML) and near-to-far-field transformation. The ZTFDTD method is then used to simulate the interaction of electromagnetic wave with plasma. Using a simplified two-dimensional model, the stealth effect of inhomogeneous, unmagnetized plasma is studied both in different electron densities of plasma, different electromagnetic wave frequencies and different plasma collision frequencies. The numerical results indicate that plasma stealth is effective in theory and a reasonable selection with the plasma parameters that can greatly enhance the effectiveness of plasma stealth. __________ Translated from Journal of Huazhong University of Science and Technology (Nature Science Edition), 2006, 35(6): 57–59 [译自: 华中科技大学学报(自然科学版)]     

Delay-dependent robust H ∞ controller design for a class of nonlinear uncertainty time-delay systems with input delay

Based on an appropriate Lyapunov function, this paper analyzes the design of a delay-dependent robust H _∞ state feedback control, with a focus on a class of nonlinear uncertainty linear time-delay systems with input delay using linear matrix inequalities. Under the condition that the nonlinear uncertain functions are gain bounded, a sufficient condition dependent on the delays of the state and input is presented for the existence of H _∞ controller. The proposed controller not only stabilized closed-loop uncertain systems but also guaranteed a prescribed H _∞ norm bound of closed-loop transfer matrix from the disturbance to controlled output. By solving a linear matrix inequation, we can obtain the robust H _∞ controller. An example is given to show the effectiveness of the proposed method. __________ Translated from Journal of Nanjing University of Aeronautics and Astronautics, 2007, 39(2): 159–163 [译自: 南京航空航天大学学报]     

Error-space estimate method for generalized synergic target tracking

To improve the tracking accuracy and stability of an optic-electronic target tracking system, the concept of generalized synergic target and an algorithm named error-space estimate method is presented. In this algorithm, the motion of target is described by guide data and guide errors, and then the maneuver of the target is separated into guide data and guide errors to reduce the maneuver level. Then state estimate is implemented in target state-space and error-space respectively, and the prediction data of target position are acquired by synthesizing the filtering data from target state-space according to kinematic model and the prediction data from errorspace according to guide error model. Differing from typical multi-model method, the kinematic and guide error models work concurrently rather than switch between models. Experiment results show that the performance of the algorithm is better than Kalman filter and strong tracking filter at the same maneuver level. __________ Translated from Journal of University of Electronic Science and Technology of China, 2007, 36(2): 217–219 [译自: 电子科技大学学报]     

Blind source separation algorithm for communication complex signals in communication reconnaissance

Most blind source separation algorithms are only applicable to real signals, while in communication reconnaissance processed signals are complex. To solve this problem, a blind source separation algorithm for communication complex signals is deduced, which is obtained by adopting the Kullback-Leibler divergence to measure the signals’ independence. On the other hand, the performance of natural gradient is better than that of stochastic gradient, thus the natural gradient of the cost function is used to optimize the algorithm. According to the conclusion that the signal’s mixing matrix after whitening is orthogonal, we deduce the iterative algorithm by constraining the separating matrix to an orthogonal matrix. Simulation results show that this algorithm can efficiently separate the source signals even in noise circumstances. __________ Translated from Journal of Huazhong University of Science and Technology (Natural Science Edition), 2007, 35(4): 33–36 [译自: 华中科技大学学报(自然科学版)]     

Large aperture static interferential multispectral image compression with motion compensation and region of interest coding

To perform better on interferential multispectral image compression, wavelet transform based on motion compensation and region of interest coding and asymmetric zerotree was proposed. According to the movement in the images and the characters of spectrum, the motion compensation and raising coefficients of intensive interference area were used in this wavelet. In this way, the relativity among the spectra is reduced and the intensive interference area coefficients can be coded preferentially. The asymmetric zerotree was proposed due to the unsymmetrical structure of images formed by the wavelet. Experimental results show that with eightfold compression, this algorithm outperforms the three-dimensional set partitioning in hierarchical trees (3DSPIHT) in the range of 0.35–0.49 dB in power signal-to-noise ratio (PSNR) and outperforms the 2DSPIHT in the range of 2.24–2.62 dB in PSNR. Compared to joint picture expert group 2000 (JPEG2000) upscaling method, the effect of intensive interference area is also improved 0.29–0.38 dB in PSNR. Meanwhile, the average of mean square error of spectra within 46 spectrum bands is reduced to 9.69. Translated from Journal of Xi’an Jiaotong University, 2006, 40(4):449–453 [译自: 西安交通大学学报]     

Medical image lossless compression based on combining an integer wavelet transform with DPCM

To improve the classical lossless compression of low efficiency, a method of image lossless compression with high efficiency is presented. Its theory and the algorithm implementation are introduced. The basic approach of medical image lossless compression is then briefly described. After analyzing and implementing differential plus code modulation (DPCM) in lossless compression, a new method of combining an integer wavelet transform with DPCM to compress medical images is discussed. The analysis and simulation results show that this new method is simpler and useful. Moreover, it has high compression ratio in medical image lossless compression. __________ Translated from Journal of Northeastern University (Natural Science), 2007, 28(10): 1454–1457 [译自 : 东北大学学报 (自然科学版)]     

A distributed routing algorithm for data aggregation in wireless sensor networks

Considering the impact of aggregation cost on the performance of aggregation routes in wireless sensor networks, an aggregation-decision-based distributed routing algorithm for data aggregation is proposed. When source nodes arrive or leave, the algorithm can calculate the aggregation benefit according to data correlation, aggregation cost and transmission cost. Then the algorithm will adaptively make aggregation and routing decisions based on aggregation benefit. Therefore, it can jointly optimize the aggregation and transmission costs and reduce the energy consumption for data gathering. This distributed algorithm makes all the decisions only relying on the local information. Hence, the routing maintenance cost is limited. Simulation results show that the energy consumption difference between this distributed online algorithm and the previous offline one is within 17% under any network conditions. __________ Translated from Journal of Beijing University of Posts and Telecommunications, 2007, 30(1): 9–13 [译自: 北京邮电大学学报]     

基于卡尔曼滤波算法GPS校钟系统的设计

电网时间统一主站系统主要由铯钟源、GPS校钟系统、分频钟设备以及频标放大器和脉冲放大器等组成.其中GPS校钟设备测量GPS秒信号和分频钟秒信号的时差,并利用卡尔曼滤波算法对时差数据进行滤波平滑,调整分频钟的秒信号与GPS秒信号对齐,再经脉冲放大器输出作为主站系统的时间基准用来同步整个电网时间.文章给出了校钟设备的设计方...     

Subspace clustering through attribute clustering

Many recently proposed subspace clustering methods suffer from two severe problems. First, the algorithms typically scale exponentially with the data dimensionality or the subspace dimensionality of clusters. Second, the clustering results are often sensitive to input parameters. In this paper, a fast algorithm of subspace clustering using attribute clustering is proposed to overcome these limitations. This algorithm first filters out redundant attributes by computing the Gini coefficient. To evaluate the correlation of every two non-redundant attributes, the relation matrix of non-redundant attributes is constructed based on the relation function of two dimensional united Gini coefficients. After applying an overlapping clustering algorithm on the relation matrix, the candidate of all interesting subspaces is achieved. Finally, all subspace clusters can be derived by clustering on interesting subspaces. Experiments on both synthesis and real datasets show that the new algorithm not only achieves a significant gain of runtime and quality to find subspace clusters, but also is insensitive to input parameters. __________ Translated from Journal of Beijing University of Posts and Telecommunications, 2007, 30(3): 1–5 [译自: 北京邮电大学学报]     

Indoor and outdoor people detection and shadow suppression by exploiting HSV color information

An adaptive background model based on maximum statistical probability and a shadow suppression scheme for indoor and outdoor people detection by exploiting hue saturation value (HSV) color information is proposed. To obtain the initial background scene, the frequency of R, G, and B component values for each pixel at the same position in the learning sequence are respectively calculated; the R, G, and B component values with the biggest ratios are incorporated to model the initial background. The background maintenance, or the socalled background re-initiation, is also proposed to adapt to scene changes such as illumination changes and scene geometry changes. Moving cast shadows generally exhibit a challenge for accurate moving target detection. Based on the observation that a shadow cast on a background region lowers its brightness but does not change its chromaticity significantly, we address this problem in the article by exploiting HSV color information. In addition, quantitative metrics is introduced to evaluate the algorithm on a benchmark suite of indoor and outdoor video sequences. The experimental results are given to show the performance of the algorithm. __________ Translated from Journal of Huaqiao University (Natural Science), 2007, 28(1): 30–33 [译自: 华侨大学学报 (自然科学版)]     

Characteristics of high frequency radio wave propagated in heated ionospheric regions

A two-dimensional Ohm heating theoretic model in the magnetizing ionosphere and a ray-tracing model in a discrete ionosphere background are used to analyze quantitatively the characteristics (mainly the Doppler shift and the phase shift) of the over-the-horizon radar (OTHR) wave, which propagates through the ionospheric region heated by high frequency radio wave. The simulation results about the Doppler and the phase shift are obtained within two minutes after the heater is on. Preliminary conclusions are given by comparing the numerical results with experimental data. __________ Translated from Chinese Journal of Radio Science, 2008, 23(3): 466–470 [译自: 电波科学学报]     

Robust adaptive beamforming algorithm based on Bayesian approach

The performance of adaptive array beamforming algorithms substantially degrades in practice because of a slight mismatch between actual and presumed array responses to the desired signal. A novel robust adaptive beamforming algorithm based on Bayesian approach is therefore proposed. The algorithm responds to the current environment by estimating the direction of arrival (DOA) of the actual signal from observations. Computational complexity of the proposed algorithm can thus be reduced compared with other algorithms since the recursive method is used to obtain inverse matrix. In addition, it has strong robustness to the uncertainty of actual signal DOA and makes the mean output array signal-to-interference-plus-noise ratio (SINR) consistently approach the optimum. Simulation results show that the proposed algorithm is better in performance than conventional adaptive beamforming algorithms. __________ Translated from Journal of Northeastern University (Natural Science), 2007, 28(6): 793–796 [译自: 东北大学学报 (自然科学版)]     

Positioning models and systems based on digital television broadcasting signals

The requirement and feasibility of the positioning system using digital television (DTV) broadcasting signals are analyzed. The principle of DTV positioning on the basis of frame synchronization is brought forward and the ranging characteristic is studied that the observables are asynchronously measured during the same epoch interval. The models of the pseudo-range observation and Doppler carrier phase integral are researched. The system observation and state equations are presented on the basis of the above models. The simulation results showed that DTV positioning technology could remarkably improve the precision of system state estimates using smoothing methods for positioning systems or integrated navigation systems. The DTV positioning that has a sub-meter level ranging error and meter level positioning accuracy can parallel with and even taken as a beneficial substitute for the tradition positioning technology. __________ Translated from Journal of Southeast University (Natural Science Edition), 2006, 36(5): 690–694 [译 自: 东南大学学报(自然科学版)]     

The holographic reconstructing algorithm and its error analysis about phase-shifting phase measurement

Phase-shifting measurement and its error estimation method were studied according to the holographic principle. A function of synchronous superposition of object complex amplitude reconstructed from N-step phase-shifting through one integral period (N-step phase-shifting function for short) was proposed. In N-step phase-shifting measurement, the interferograms are seen as a series of in-line holograms and the reference beam is an ideal parallel-plane wave. So the N-step phase-shifting function can be obtained by multiplying the interferogram by the original reference wave. In ideal conditions, the proposed method is a kind of synchronous superposition algorithm in which the complex amplitude is separated, measured and superposed. When error exists in measurement, the result of the N-step phase-shifting function is the optimal expected value of the least-squares fitting method. In the above method, the N+1-step phase-shifting function can be obtained from the N-step phase-shifting function. It shows that the N-step phase-shifting function can be separated into two parts: the ideal N-step phase-shifting function and its errors. The phase-shifting errors in N-steps phase-shifting phase measurement can be treated the same as the relative errors of amplitude and intensity under the understanding of the N+1-step phase-shifting function. The difficulties of the error estimation in phase-shifting phase measurement were restricted by this error estimation method. Meanwhile, the maximum error estimation method of phase-shifting phase measurement and its formula were proposed. Translated from Acta Optica Sinica, 2006, 26(9): 1 367–1 371 [译自: 光学学报]     

Simulation of a mass-spring model for global deformation

This article addresses a largely open problem in haptic simulation and rendering: contact force and deformation modeling for haptic simulation of a discrete globe mass-spring model, especially for global deformation. The mass-spring system is composed of nodes connected with radially distributed springs. We tackle the problem using the theory of virtual work, and relations between the virtual force and nodal displacements are analyzed to obtain elastic deformations. The global deformation is controlled by the total nodal deformations based on a force equation at each node. The simulation results verify the efficiency of the contact force and deformation model with reasonable realism. __________ Translated from Journal of Southeast University (Natural Science Edition), 2007, 37(5): 849–852 [译自 : 东南大学学报 (自然科学版)]     

Research on food-chain algorithm and its parameters

Based on the characteristics of colony emergence of artificial organisms, their dynamic interaction with the environment, and the food-chain crucial to the life system, the rules of local activities of artificial organisms at different levels are defined. The article proposes an artificial life-based algorithm, which is referred to as the food-chain algorithm. This algorithm optimizes computation by simulating the evolution of natural ecosystems and the information processing mechanism of natural organisms. The definition, idea and flow of the algorithm are introduced, and relevant rules on metabolic energy and change in the surroundings where artificial-life individuals live are depicted. Furthermore, key parameters of the algorithm are systematically analyzed. Test results show that the algorithm has quasi-life traits that include being autonomous, evolutionary, and self-adaptive. These traits are highly fit for optimization problems of life-like systems such as the location-allocation problem of a distribution network system. __________ Translated from Journal of Northeastern University (Natural Science), 2007, 28(7): 993–997 [译自: 东北大学学报(自然科学版)]