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2003 Vol. 25, No. 6
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2003, 25(6): 721-727.
Abstract:
An important, problem in the field of signal processing, sequence of infrared image detection which arouses peoples attention widely is the detection and tracking of dim moving targets in very low Signal-to-Noise Ratio (SNR) or signal-to-clutter ratio environment. In fact, dynamic programming is a problem of multi-stage decision, and Dynamic Programming Algorithm (DPA) is an effective approach which was adopted during the process of Track-Before-Detect(TBD). In current work, the mechanism of dynamic programming algorithm is analyzed, and a number of technical innovations that improve the performance of DPA are presented. Simulation results show this approach has high ability of detection for dim moving targets, and achieves 3~5dB SNR. gains comparable to those of other detection algorithms.
An important, problem in the field of signal processing, sequence of infrared image detection which arouses peoples attention widely is the detection and tracking of dim moving targets in very low Signal-to-Noise Ratio (SNR) or signal-to-clutter ratio environment. In fact, dynamic programming is a problem of multi-stage decision, and Dynamic Programming Algorithm (DPA) is an effective approach which was adopted during the process of Track-Before-Detect(TBD). In current work, the mechanism of dynamic programming algorithm is analyzed, and a number of technical innovations that improve the performance of DPA are presented. Simulation results show this approach has high ability of detection for dim moving targets, and achieves 3~5dB SNR. gains comparable to those of other detection algorithms.
2003, 25(6): 728-734.
Abstract:
When the noises are spatially correlated, the time delay methods based on second order statistic will be useless. In this paper a kind of adaptive time delay estimation method based on third order statistic is provided, and its convergence is analyzed. Finally , simulation results demonstrate that this approach can effectively depress Gaussian correlated noise.
When the noises are spatially correlated, the time delay methods based on second order statistic will be useless. In this paper a kind of adaptive time delay estimation method based on third order statistic is provided, and its convergence is analyzed. Finally , simulation results demonstrate that this approach can effectively depress Gaussian correlated noise.
2003, 25(6): 735-740.
Abstract:
A new way to analysis nonstationary stochastic process is to divide it into piece-wise stationary stochastic process. Djuric(1992) used Bayes method to estimate the parameters, which can optimally divide the nonstationary stochastic process into stationary stochastic pro-cess. Some authors estimated the optimum parameters through calculating recursively the multivariate conditional likelihood function, which made the computation very complex. Bas-ing on some natural characteristics of AR. mode, a new recursive method is provided, which can improve the computation efficiently, to estimate the optimum parameters.
A new way to analysis nonstationary stochastic process is to divide it into piece-wise stationary stochastic process. Djuric(1992) used Bayes method to estimate the parameters, which can optimally divide the nonstationary stochastic process into stationary stochastic pro-cess. Some authors estimated the optimum parameters through calculating recursively the multivariate conditional likelihood function, which made the computation very complex. Bas-ing on some natural characteristics of AR. mode, a new recursive method is provided, which can improve the computation efficiently, to estimate the optimum parameters.
2003, 25(6): 741-746.
Abstract:
This paper deals with the problem of adaptive array beamforming for cyclosta-tionary signals-a novel robust cyclostationary space-time beamforming algorithm. In this algorithm, multiple lag parameters and the spectrum correlation property are used to exploit the cyclic statistical information and time domain characteristics of signals sufficiently and ef-fectively. Moreover, this method remedies the lack of space domain information, and it is an extension from space domain to space-time domain. Therefore the ability to select the desired signals and supress the noise and interfering signals is improved. The simulation results show the effectiveness and robustness of the algorithm.
This paper deals with the problem of adaptive array beamforming for cyclosta-tionary signals-a novel robust cyclostationary space-time beamforming algorithm. In this algorithm, multiple lag parameters and the spectrum correlation property are used to exploit the cyclic statistical information and time domain characteristics of signals sufficiently and ef-fectively. Moreover, this method remedies the lack of space domain information, and it is an extension from space domain to space-time domain. Therefore the ability to select the desired signals and supress the noise and interfering signals is improved. The simulation results show the effectiveness and robustness of the algorithm.
2003, 25(6): 747-754.
Abstract:
Compression of multispectral imagery is based on reducing redundancies in both the spatial domain and the spectral domain. In this paper, a new hybrid compression algorithm using partitioning DPCM and SPIHT is proposed on the base of analyzing the spatial and spectral correlation features of multispectral imagery. A first-order predictor is designed for de-correlating the spectral redundancy and creating error images for later use. Because the image similarities among adjacent spectrum bands are different with the change of spectrum, the whole multispectral image sequence is partitioned into several subsets, and then DPCM predictors are designed separately for each image subset. After de-correlating spectral redundancy, a efficient wavelet coding method, SPIHT, is used to compress error images created by partitioning DPCM algorithm. The experimental results from simulated multispectral images and practical 64-band multispectral images have shown that the algorithm is fast, efficient and practical.
Compression of multispectral imagery is based on reducing redundancies in both the spatial domain and the spectral domain. In this paper, a new hybrid compression algorithm using partitioning DPCM and SPIHT is proposed on the base of analyzing the spatial and spectral correlation features of multispectral imagery. A first-order predictor is designed for de-correlating the spectral redundancy and creating error images for later use. Because the image similarities among adjacent spectrum bands are different with the change of spectrum, the whole multispectral image sequence is partitioned into several subsets, and then DPCM predictors are designed separately for each image subset. After de-correlating spectral redundancy, a efficient wavelet coding method, SPIHT, is used to compress error images created by partitioning DPCM algorithm. The experimental results from simulated multispectral images and practical 64-band multispectral images have shown that the algorithm is fast, efficient and practical.
2003, 25(6): 755-762.
Abstract:
This paper discusses the generalized definition of image registration and proposes a new measure of image registration-the Alignment Metric(AM). This metric can effectively describe the degree of match of two images with different gray level properties. As a result, the problem of image registration is turned into the maximization of the AM. The new criterion can be used to register multi-modal images including the images with different gray level properties. The Powells direction set method with multi-resolution is used to search for a global maximum of the AM. The images can then be registered automatically without the need of the previously located control points or landmark points. Experiments using multi-modal medical and remote sensing images demonstrate the effectiveness of the method.
This paper discusses the generalized definition of image registration and proposes a new measure of image registration-the Alignment Metric(AM). This metric can effectively describe the degree of match of two images with different gray level properties. As a result, the problem of image registration is turned into the maximization of the AM. The new criterion can be used to register multi-modal images including the images with different gray level properties. The Powells direction set method with multi-resolution is used to search for a global maximum of the AM. The images can then be registered automatically without the need of the previously located control points or landmark points. Experiments using multi-modal medical and remote sensing images demonstrate the effectiveness of the method.
2003, 25(6): 763-770.
Abstract:
A vision model of user avatar with nine freedoms based-on simple convergent binoc-ular stereo vision is proposed and used to imaging and transformation in virtual scene. The formulas of imaging in left and right virtual camera about the virtual scene points are educed with its world coordinate values and the nine freedoms variables of the user avatar vision model. The equations are deduced about the relationship between the parallax of the imaging points in left and right images about the scene point projected by virtual binocular camera and depth in-formation of the scene point relative to the original points of the observation coordinate system. The results of the simulation experiment prove the feasibility of the model and the reliability of the algorithmic method in this paper. Simultaneously, it is proved that the vision model of user avatar with nine freedoms is more effective, more practical and more vicinal to human beings visional habit.
A vision model of user avatar with nine freedoms based-on simple convergent binoc-ular stereo vision is proposed and used to imaging and transformation in virtual scene. The formulas of imaging in left and right virtual camera about the virtual scene points are educed with its world coordinate values and the nine freedoms variables of the user avatar vision model. The equations are deduced about the relationship between the parallax of the imaging points in left and right images about the scene point projected by virtual binocular camera and depth in-formation of the scene point relative to the original points of the observation coordinate system. The results of the simulation experiment prove the feasibility of the model and the reliability of the algorithmic method in this paper. Simultaneously, it is proved that the vision model of user avatar with nine freedoms is more effective, more practical and more vicinal to human beings visional habit.
2003, 25(6): 771-776.
Abstract:
This article presents a passive DOA jointed TOA location algorithm and the corresponding analysis of the location accuracy. A set of simulations are implemented to compare the DOA jointed TOA, DOA, and TOA location algorithm. Results show that the proposed algorithm has the best performance in terms of both location accuracy and system requirement. Overall speaking, it is a practical passive location method.
This article presents a passive DOA jointed TOA location algorithm and the corresponding analysis of the location accuracy. A set of simulations are implemented to compare the DOA jointed TOA, DOA, and TOA location algorithm. Results show that the proposed algorithm has the best performance in terms of both location accuracy and system requirement. Overall speaking, it is a practical passive location method.
2003, 25(6): 777-783.
Abstract:
Reconstruction algorithms for Synthetic Aperture Sonar (SAS) are discussed, and choice of SAS parameters and parallel structures are studied in this paper. A SHARC-based real-time processing system for SAS imaging is presented. Two pipelines are used in the system. The first pipeline makes full use of pulse repetition interval and proceed data sequentially, and the second one focuses image data in frame. Therefore, SAS image is reconstructed with only one stage time-consumption though two stages are used. Moreover, parallel processing are used in both stages to meet real-time requirement.
Reconstruction algorithms for Synthetic Aperture Sonar (SAS) are discussed, and choice of SAS parameters and parallel structures are studied in this paper. A SHARC-based real-time processing system for SAS imaging is presented. Two pipelines are used in the system. The first pipeline makes full use of pulse repetition interval and proceed data sequentially, and the second one focuses image data in frame. Therefore, SAS image is reconstructed with only one stage time-consumption though two stages are used. Moreover, parallel processing are used in both stages to meet real-time requirement.
2003, 25(6): 784-789.
Abstract:
The imaging method with stepped frequency signal for low-altitude target in strong ground clutter is presented. The format of normal stepped frequency signal is modified slightly to satisfy ISAR imaging. The ground clutter is filtered through the one-order canceller, then after the motion compensation is completed, the images of the target are obtained. The validity of the imaging method is proven by simulation results.
The imaging method with stepped frequency signal for low-altitude target in strong ground clutter is presented. The format of normal stepped frequency signal is modified slightly to satisfy ISAR imaging. The ground clutter is filtered through the one-order canceller, then after the motion compensation is completed, the images of the target are obtained. The validity of the imaging method is proven by simulation results.
2003, 25(6): 790-794.
Abstract:
The full wave FDTD method is used to analysis some Hilbert fractal antenna. The computational results are in good agreement with the experiment, in the document. The results show that Hilbert fractal geometries can be implemented to miniaturize the size of the antenna, too. The reduction level of the Hilbert fractal antenna is about 6/7, at the same time, the higher the fractal order, the more reduction of the antenna size. Furthermore, the far field pattern remain almost the same at the resonant frequencies.
The full wave FDTD method is used to analysis some Hilbert fractal antenna. The computational results are in good agreement with the experiment, in the document. The results show that Hilbert fractal geometries can be implemented to miniaturize the size of the antenna, too. The reduction level of the Hilbert fractal antenna is about 6/7, at the same time, the higher the fractal order, the more reduction of the antenna size. Furthermore, the far field pattern remain almost the same at the resonant frequencies.
2003, 25(6): 795-800.
Abstract:
Based on the characteristics of Frequency Hopping(FH) system, the union-upper-bound of Block Turbo Codes (BTCs) in the short wave FH system is analyzed and deduced. The union-upper-bound equation for BTCs is given out in the barrage jamming. The numerical simulation of the BTCs is performed in short-wave jamming channel. When the signal-to-jamming ratio is 30dB, and signal-to-noise ratio is 20dB, simulation results show that using BTCs in FH system can reduce the bit error rate from 10-3 to 10-5.
Based on the characteristics of Frequency Hopping(FH) system, the union-upper-bound of Block Turbo Codes (BTCs) in the short wave FH system is analyzed and deduced. The union-upper-bound equation for BTCs is given out in the barrage jamming. The numerical simulation of the BTCs is performed in short-wave jamming channel. When the signal-to-jamming ratio is 30dB, and signal-to-noise ratio is 20dB, simulation results show that using BTCs in FH system can reduce the bit error rate from 10-3 to 10-5.
2003, 25(6): 801-807.
Abstract:
An out-loop power control model for the cdma2000 reverse link is established, and the relationship between the inner-loop and the out-loop is revealed. As a result, a simple estimation method for Frame Error Rate (FER) is proposed and its performance is analyzed. Based on the model, an optimization algorithm for the out-loop power control is proposed which aims to jointly reduce the transmit power and FER variation. It can guarantee target FER while keeps transmit power at, the minimum level, resulting an optimal system performance. The algorithm allows the weighting factors to be adjusted to satisfy different Quality of Service (QoS) requirements, hence provides great flexibility. Finally, computer simulation is performed to show that, the model is appropriate and the optimization algorithm is effective and correct.
An out-loop power control model for the cdma2000 reverse link is established, and the relationship between the inner-loop and the out-loop is revealed. As a result, a simple estimation method for Frame Error Rate (FER) is proposed and its performance is analyzed. Based on the model, an optimization algorithm for the out-loop power control is proposed which aims to jointly reduce the transmit power and FER variation. It can guarantee target FER while keeps transmit power at, the minimum level, resulting an optimal system performance. The algorithm allows the weighting factors to be adjusted to satisfy different Quality of Service (QoS) requirements, hence provides great flexibility. Finally, computer simulation is performed to show that, the model is appropriate and the optimization algorithm is effective and correct.
2003, 25(6): 808-815.
Abstract:
A traffic trunk can be characterized by administrator in optical traffic engineering, and an attribute of a traffic trunk is a parameter assigned to it which influences its behav-ioral characteristics. The priority attribute defines the relative importance of traffic trunks. If a constraint-based routing framework is used, then priorities become very important in im-plementations permitting preemption. Preemption is used to assure that high priority traffic trunks can always be routed through relatively favorable paths at connection establishment within a differentiated services environment. The main objective of this paper is to discuss how to preempt at Label Switch Path(LSP) establishment according to the attribute of traffic trunk, and two new schemes, Minimum Connection Bandwidth Interrupt Method(MCBIM) and Minimum Connection Number Interrupt Method (MCNIM), arc presented. They make full use of established LSP information to determine how to route an arriving request. Simulation results show that these two schemes can improve the performance of the network significantly.
A traffic trunk can be characterized by administrator in optical traffic engineering, and an attribute of a traffic trunk is a parameter assigned to it which influences its behav-ioral characteristics. The priority attribute defines the relative importance of traffic trunks. If a constraint-based routing framework is used, then priorities become very important in im-plementations permitting preemption. Preemption is used to assure that high priority traffic trunks can always be routed through relatively favorable paths at connection establishment within a differentiated services environment. The main objective of this paper is to discuss how to preempt at Label Switch Path(LSP) establishment according to the attribute of traffic trunk, and two new schemes, Minimum Connection Bandwidth Interrupt Method(MCBIM) and Minimum Connection Number Interrupt Method (MCNIM), arc presented. They make full use of established LSP information to determine how to route an arriving request. Simulation results show that these two schemes can improve the performance of the network significantly.
2003, 25(6): 816-823.
Abstract:
In this paper, the Round-Robin crossbar scheduling algorithm based on spirality is proposed. It addresses the R-R pointers in scheduling and iteration, respectively, to avoid the synchronic of pointers. And it pipelines the polling of input ports and the steps of iteration in 2 dimensional. When the number of ports is less than 32, it has simple logic and performs better. In addition, by weighting the R-R, it can provide high throughput for non-uniform traffic.
In this paper, the Round-Robin crossbar scheduling algorithm based on spirality is proposed. It addresses the R-R pointers in scheduling and iteration, respectively, to avoid the synchronic of pointers. And it pipelines the polling of input ports and the steps of iteration in 2 dimensional. When the number of ports is less than 32, it has simple logic and performs better. In addition, by weighting the R-R, it can provide high throughput for non-uniform traffic.
2003, 25(6): 824-830.
Abstract:
In optical network, for anyone connection in order to provide protection mechanism, not only one working path for the traffic flow should be computed, but also one backup path should be provided, and they should be physical-disjoint. This paper proposes one heuristic algorithm, which can compute two SRLG-disjoint paths simultaneously, and the total cost of the two paths is near optimal. In this paper, some simulations and analysis are also given out.
In optical network, for anyone connection in order to provide protection mechanism, not only one working path for the traffic flow should be computed, but also one backup path should be provided, and they should be physical-disjoint. This paper proposes one heuristic algorithm, which can compute two SRLG-disjoint paths simultaneously, and the total cost of the two paths is near optimal. In this paper, some simulations and analysis are also given out.
2003, 25(6): 831-837.
Abstract:
This paper describes a kind of micro-array Light Addressable Potentionietric Sen-sor(LAPS) system based on the Electrolyte-Insulator-Semiconductor (EIS) structure, in which electronic technology, optical technology and mechanical technology are applied. The mecha-nism of the LAPS is investigated and a trial specimen of the LAPS is developed ? The research work finds how the thickness of the chip, the linearity of the I-V curve and frequency affect the performance of the LAPS system, and obtains testing results of urea, penicillin and pH value.
This paper describes a kind of micro-array Light Addressable Potentionietric Sen-sor(LAPS) system based on the Electrolyte-Insulator-Semiconductor (EIS) structure, in which electronic technology, optical technology and mechanical technology are applied. The mecha-nism of the LAPS is investigated and a trial specimen of the LAPS is developed ? The research work finds how the thickness of the chip, the linearity of the I-V curve and frequency affect the performance of the LAPS system, and obtains testing results of urea, penicillin and pH value.
2003, 25(6): 838-843.
Abstract:
A large of number sample data is needed by the blind channel equalization based on HOS (High Order Statistics). The performance of equalization was found to be poor in fast change environment or with short data samples. The blind equalization using second order statistics has drawn considerable attention recently. The performance with fast convergence makes it useful in the mobile communications or short-wave communications. The algorithm for subspace method based on the blind channel identification/equalization using Kalman filter equation is presented, which needs a few data. Simulation results show that the algorithm is effective.
A large of number sample data is needed by the blind channel equalization based on HOS (High Order Statistics). The performance of equalization was found to be poor in fast change environment or with short data samples. The blind equalization using second order statistics has drawn considerable attention recently. The performance with fast convergence makes it useful in the mobile communications or short-wave communications. The algorithm for subspace method based on the blind channel identification/equalization using Kalman filter equation is presented, which needs a few data. Simulation results show that the algorithm is effective.
2003, 25(6): 844-846.
Abstract:
Firstly, the energy distribution in different wavelet scale space and the fractal dimension of underwater sonar echoes are discussed. Then, these feature vectors are utilized to classify the real echoes, and weight these features according to their own degree of dispersion. Finally, a minimum distance classifier is used in the classification procedure, and experimental results demonstrate the efficiency of the method.
Firstly, the energy distribution in different wavelet scale space and the fractal dimension of underwater sonar echoes are discussed. Then, these feature vectors are utilized to classify the real echoes, and weight these features according to their own degree of dispersion. Finally, a minimum distance classifier is used in the classification procedure, and experimental results demonstrate the efficiency of the method.
2003, 25(6): 847-850.
Abstract:
This paper presents the method for recognizing Chinese speech by utilizing DSP. Through experiment of Chinese speech recognition in the noise environment of outdoor, the effectiveness of the method is confirmed.
This paper presents the method for recognizing Chinese speech by utilizing DSP. Through experiment of Chinese speech recognition in the noise environment of outdoor, the effectiveness of the method is confirmed.
2003, 25(6): 851-854.
Abstract:
XTR is a new public key system based on a method to represent elements of a subgroup of a multiplicative group of a finite field. Compared to RSA and ECC, XTR keys are much smaller than RSA keys of equivalent security, and at most twice as big as ECC keys, but parameter and key selection for XTR are much faster than ECC. Based on XTR system by using traditional blind signature schemes based on discrete logarithm problem and fast method for computing the trace of the elements in the finite field, two blind signature schemes are presented in this paper, the security of which is equivalence to solving XTR-DL problem while the datum is only as 1/3 as that of the previous schemes.
XTR is a new public key system based on a method to represent elements of a subgroup of a multiplicative group of a finite field. Compared to RSA and ECC, XTR keys are much smaller than RSA keys of equivalent security, and at most twice as big as ECC keys, but parameter and key selection for XTR are much faster than ECC. Based on XTR system by using traditional blind signature schemes based on discrete logarithm problem and fast method for computing the trace of the elements in the finite field, two blind signature schemes are presented in this paper, the security of which is equivalence to solving XTR-DL problem while the datum is only as 1/3 as that of the previous schemes.
2003, 25(6): 855-860.
Abstract:
An architecture of an all-digitized QAM receiver applicable for digital video broad-casting for cable television is proposed in this paper. The digital implementation of the QAM demodulator, including carrier recovery, symbol synchronization, automatic gain control and adaptive equalization is discussed. Loop parameters of the receiver are investigated via simula-tion. Finally, bit error rate of the receiver under AWGN channel is shown. Simulation results demonstrate that the receiver has a good performance, and is easy to implement digitally.
An architecture of an all-digitized QAM receiver applicable for digital video broad-casting for cable television is proposed in this paper. The digital implementation of the QAM demodulator, including carrier recovery, symbol synchronization, automatic gain control and adaptive equalization is discussed. Loop parameters of the receiver are investigated via simula-tion. Finally, bit error rate of the receiver under AWGN channel is shown. Simulation results demonstrate that the receiver has a good performance, and is easy to implement digitally.
2003, 25(6): 861-864.
Abstract:
The unique steady state of nonlinear circuits is studied by weakly structured per-turbation theory. By means of this method, a new criterion of the unique steady state of the nonlinear circuits is obtained. The restriction to the elements of circuits is just the slope of the constitutive relation is bounded, which is much looser than the classic results published previously. The new criterion in this paper has much wider applicable range than the results already known.
The unique steady state of nonlinear circuits is studied by weakly structured per-turbation theory. By means of this method, a new criterion of the unique steady state of the nonlinear circuits is obtained. The restriction to the elements of circuits is just the slope of the constitutive relation is bounded, which is much looser than the classic results published previously. The new criterion in this paper has much wider applicable range than the results already known.
