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2002 Vol. 24, No. 8
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2002, 24(8): 1009-1016.
Abstract:
A new automatic video sequence segmentation algorithm that extracts moving objects is presented in this paper. The algorithm exploits the local variation in the L~*u~*v~* space, and combines it with motion information to separate foreground objects from the background. A new image segmentation algorithm based on graphic-theoretic approach is first employed to generate various regions according to local variation. Next, moving regions are identified by a new filter criterion, which measures the deviation of the estimated local motion from the synthesized global motion. In order to increase the temporal and spatial consistency of extracted objects, moving regions are tracked by a region-based affine motion model. A two-dimensional binary model is derived for the objects and tracked throughout the sequence by a Hausdorff object tracker. The proposed algorithm is evaluated for several typical MPEG-4 test sequences. Experimental results demonstrate the performance of the proposed algorithm.
A new automatic video sequence segmentation algorithm that extracts moving objects is presented in this paper. The algorithm exploits the local variation in the L~*u~*v~* space, and combines it with motion information to separate foreground objects from the background. A new image segmentation algorithm based on graphic-theoretic approach is first employed to generate various regions according to local variation. Next, moving regions are identified by a new filter criterion, which measures the deviation of the estimated local motion from the synthesized global motion. In order to increase the temporal and spatial consistency of extracted objects, moving regions are tracked by a region-based affine motion model. A two-dimensional binary model is derived for the objects and tracked throughout the sequence by a Hausdorff object tracker. The proposed algorithm is evaluated for several typical MPEG-4 test sequences. Experimental results demonstrate the performance of the proposed algorithm.
2002, 24(8): 1017-1021.
Abstract:
Possibilistic partition coefficient which based on possibilistic distribution descriptor has decreasing tendency as the classification number increasing and does not directly relate to the geometry structure of data set. To consider the geometry structure information of data set, new clustering validity functions are defined by modify possibilistic partition coefficient. Experimental results show that the new methods have good classification performance.
Possibilistic partition coefficient which based on possibilistic distribution descriptor has decreasing tendency as the classification number increasing and does not directly relate to the geometry structure of data set. To consider the geometry structure information of data set, new clustering validity functions are defined by modify possibilistic partition coefficient. Experimental results show that the new methods have good classification performance.
2002, 24(8): 1022-1027.
Abstract:
The LMS algorithm is widely used in various signal processing fields such as radar, communication, etc. due to its simplicity. It is a focus in the research on the implementation of the high-speed adaptive filter. Based on the parallel pipelined LMS (PIPLMS) algorithm, a high-speed filter implementation is proposed in this paper. This implementation has both the properties of high pipelining in the systolic structure and parallelism in the parallel structure. At the same time, the implementation presented herein also has the properties of higher throughput rate, lower power consumption, larger step size range maintained convergence behavior and faster convergence speed.
The LMS algorithm is widely used in various signal processing fields such as radar, communication, etc. due to its simplicity. It is a focus in the research on the implementation of the high-speed adaptive filter. Based on the parallel pipelined LMS (PIPLMS) algorithm, a high-speed filter implementation is proposed in this paper. This implementation has both the properties of high pipelining in the systolic structure and parallelism in the parallel structure. At the same time, the implementation presented herein also has the properties of higher throughput rate, lower power consumption, larger step size range maintained convergence behavior and faster convergence speed.
2002, 24(8): 1028-1034.
Abstract:
In this paper , the method for designing digital filters and their implementation and application via filter banks are introduced. The design of digital Hilbert filters of each scale in dyadic wavelet filter banks is particularly discussed. Moreover, this method, which based on multiscale Hilbert filtering methods, is applied to the extraction of the instantaneous frequency and obtains a better denoising result compared with the traditional DWT denoising method.
In this paper , the method for designing digital filters and their implementation and application via filter banks are introduced. The design of digital Hilbert filters of each scale in dyadic wavelet filter banks is particularly discussed. Moreover, this method, which based on multiscale Hilbert filtering methods, is applied to the extraction of the instantaneous frequency and obtains a better denoising result compared with the traditional DWT denoising method.
Design of sopot two-channel perfect reconstruction fir filter banks based on evolutionary strategies
2002, 24(8): 1035-1039.
Abstract:
This paper proposes a method based on evolutionary strategies (ES) for design ofmultiplier-less two-channel perfect-reconstruction (PR) filter banks (FB). The filter banks are jbased on the modified lifting scheme structure. A new ES given a seed is proposed to find the *sum of power-of-two (SOPOT) coefficient of the filter bank. This method requires much less 玠esign time than genetic algorithm. Finally, a PR FB with SOPOT coefficient is given as an :example to illustrate the proposed method.
This paper proposes a method based on evolutionary strategies (ES) for design ofmultiplier-less two-channel perfect-reconstruction (PR) filter banks (FB). The filter banks are jbased on the modified lifting scheme structure. A new ES given a seed is proposed to find the *sum of power-of-two (SOPOT) coefficient of the filter bank. This method requires much less 玠esign time than genetic algorithm. Finally, a PR FB with SOPOT coefficient is given as an :example to illustrate the proposed method.
2002, 24(8): 1040-1048.
Abstract:
In this paper a novel method is presented to segment gray level image through maximizing the fuzzy partition entropy of two-dimensional histogram. After the concept of fuzzy partition is briefly introduced first, a new definition of fuzzy partition entropy based on condition probability and condition entropy is presented. Then, the multi-dimensional triangular-norm is applied to construct generalized Cartesian product of non-interactive fuzzy sets, and also an approach for generating multi-dimensional fuzzy partition is presented. Finally, a new method for segmenting gray level image through maximizing the fuzzy partition entropy of two-dimensional histogram is put forward. Experiments are conducted on real object pictures, and the results show that the approach presented herein performs better than some classical threshold selection methods do.
In this paper a novel method is presented to segment gray level image through maximizing the fuzzy partition entropy of two-dimensional histogram. After the concept of fuzzy partition is briefly introduced first, a new definition of fuzzy partition entropy based on condition probability and condition entropy is presented. Then, the multi-dimensional triangular-norm is applied to construct generalized Cartesian product of non-interactive fuzzy sets, and also an approach for generating multi-dimensional fuzzy partition is presented. Finally, a new method for segmenting gray level image through maximizing the fuzzy partition entropy of two-dimensional histogram is put forward. Experiments are conducted on real object pictures, and the results show that the approach presented herein performs better than some classical threshold selection methods do.
2002, 24(8): 1049-1053.
Abstract:
A new disturbing method for noise reduction of chaotic signal is presented, and a realizing example of this method-gradient disturbing method, is proposed. The noise-reduction capability of the gradient disturbing method for chaotic signal is experimentally studied, it is shown that the gradient disturbing method can obtain fairly good noise-reduction result for chaotic signal even if the signal-to-noise-ratio is low. How to choose the parameters used in the gradient disturbing method is also experimentally studied in this paper.
A new disturbing method for noise reduction of chaotic signal is presented, and a realizing example of this method-gradient disturbing method, is proposed. The noise-reduction capability of the gradient disturbing method for chaotic signal is experimentally studied, it is shown that the gradient disturbing method can obtain fairly good noise-reduction result for chaotic signal even if the signal-to-noise-ratio is low. How to choose the parameters used in the gradient disturbing method is also experimentally studied in this paper.
2002, 24(8): 1054-1059.
Abstract:
In this paper a new algorithm for estimating frequency and quality factor based on Fade aproximants is given. Because Fade approximants can accelerate the convergence of sum in the discrete Fourier transform, this algorithm is also used in the frequency and quality factor estimation of short data series. The simulation results show that this algorithm can obtain higher frequency resolution, higher accuracy and better quality factor than FFT and spectrum estimation based on wavelet transformation.
In this paper a new algorithm for estimating frequency and quality factor based on Fade aproximants is given. Because Fade approximants can accelerate the convergence of sum in the discrete Fourier transform, this algorithm is also used in the frequency and quality factor estimation of short data series. The simulation results show that this algorithm can obtain higher frequency resolution, higher accuracy and better quality factor than FFT and spectrum estimation based on wavelet transformation.
2002, 24(8): 1060-1065.
Abstract:
In this paper, the signal model of airborne SAR moving target echo is constructed firstly, which is a chirp signal naturally. According to this feature, a new technique of SAR moving target detection based on fractional Fourier transform is proposed. The effects of coupling in time-frequency domain on signal detection are eliminated. Compare with the bilinear time-frequency distribution algorithms, the fractional Fourier transform is a linear operator, and it will not affected by the intercross terms when multiple moving targets exist. The simulation results validate the effectiveness of this technique.
In this paper, the signal model of airborne SAR moving target echo is constructed firstly, which is a chirp signal naturally. According to this feature, a new technique of SAR moving target detection based on fractional Fourier transform is proposed. The effects of coupling in time-frequency domain on signal detection are eliminated. Compare with the bilinear time-frequency distribution algorithms, the fractional Fourier transform is a linear operator, and it will not affected by the intercross terms when multiple moving targets exist. The simulation results validate the effectiveness of this technique.
2002, 24(8): 1066-1072.
Abstract:
This paper studies the fractal characteristics of multipath fading channels and proposes a novel algorithm for the channel estimation, which is basically an MMSE estimation algorithm modified by employing fractal dimension and wavelet reconstruction analyses. The algorithm can improve the estimation accuracy of multipath fading channel parameters and avoid the error propagation problem of conventional approaches. Simulation results show that the new algorithm can estimate the channel parameters more accurately compared to the MMSE method, and significantly improve the receiver bit error rate (BER) in the fast fading environment.
This paper studies the fractal characteristics of multipath fading channels and proposes a novel algorithm for the channel estimation, which is basically an MMSE estimation algorithm modified by employing fractal dimension and wavelet reconstruction analyses. The algorithm can improve the estimation accuracy of multipath fading channel parameters and avoid the error propagation problem of conventional approaches. Simulation results show that the new algorithm can estimate the channel parameters more accurately compared to the MMSE method, and significantly improve the receiver bit error rate (BER) in the fast fading environment.
2002, 24(8): 1073-1079.
Abstract:
Concerning about the feature of IP traffic, this paper propose a new Priority-Based Discarding Policy (PBDP) from the view of traffic engineering, and further more gives a advanced RED algorithm PROP (Priority-based RED Discarding Policy), which combining the virtue of RED and PBDP. Considering real-time and non-real-time traffic, simulation shows the PBDP is better than traditional discarding policy, and the PROP is the best of all.
Concerning about the feature of IP traffic, this paper propose a new Priority-Based Discarding Policy (PBDP) from the view of traffic engineering, and further more gives a advanced RED algorithm PROP (Priority-based RED Discarding Policy), which combining the virtue of RED and PBDP. Considering real-time and non-real-time traffic, simulation shows the PBDP is better than traditional discarding policy, and the PROP is the best of all.
2002, 24(8): 1080-1087.
Abstract:
This paper presents two inter-layer hand-over models based on wireless mobile multimedia services including wide-band service and narrow-band service. One is bi-directional inter-layer hand-over model, the other is single-directional inter-layer model. The new call blocking probability and the hand-over call failure probability are analyzed. The QoS degradation of wide-band hand-over calls due to the inter-layer hand-over between macro-cell layer and micro-cell layer is presented in details. Also, an algorithm on channel allocation based on this hand-over policy is described. Finally, analysis and simulation results are compared to testify the hand-over policy submitted above.
This paper presents two inter-layer hand-over models based on wireless mobile multimedia services including wide-band service and narrow-band service. One is bi-directional inter-layer hand-over model, the other is single-directional inter-layer model. The new call blocking probability and the hand-over call failure probability are analyzed. The QoS degradation of wide-band hand-over calls due to the inter-layer hand-over between macro-cell layer and micro-cell layer is presented in details. Also, an algorithm on channel allocation based on this hand-over policy is described. Finally, analysis and simulation results are compared to testify the hand-over policy submitted above.
2002, 24(8): 1088-1095.
Abstract:
A Bit Error Probability(BEP) computation formula for binary Partial-Response Continuous-Phase Modulation(PRCPM) with Differential Phase Detection(DPD) and Maximum Ratio Combining(MRC) in composite satellite mobile channel is presented in this paper, and numerical results are also given.
A Bit Error Probability(BEP) computation formula for binary Partial-Response Continuous-Phase Modulation(PRCPM) with Differential Phase Detection(DPD) and Maximum Ratio Combining(MRC) in composite satellite mobile channel is presented in this paper, and numerical results are also given.
2002, 24(8): 1096-1101.
Abstract:
It is necessary to use the reference real time TOD(Time Of Date) for synchronizing a hopping sequence with long period. There is a new view that the generation of hopping codes is a process in which the special information sequences TOD are translated by a block encoding. Today monotonously increasing TOD is a common form, but there are collides between existing generating algorithm of hopping code and monotonously increasing TOD with long period. A important task of study on generating algorithm of hopping code which is suitable for monotonously increasing TOD with long period and keeps good properties is discussed in the paper.
It is necessary to use the reference real time TOD(Time Of Date) for synchronizing a hopping sequence with long period. There is a new view that the generation of hopping codes is a process in which the special information sequences TOD are translated by a block encoding. Today monotonously increasing TOD is a common form, but there are collides between existing generating algorithm of hopping code and monotonously increasing TOD with long period. A important task of study on generating algorithm of hopping code which is suitable for monotonously increasing TOD with long period and keeps good properties is discussed in the paper.
2002, 24(8): 1102-1108.
Abstract:
This paper simplifies the adaptive parallel interference cancellation (PIC) scheme into a ne method named soft-decision variant averaging amplitude estimation PIC technology. Relative to the adaptive PIC, the new method cuts down large amount of computational complexity, furthermore, it has better robustness than the adaptive PIC method. The simulations indicate that when a single sensor is used at the base station, the new method performs worse than the adaptive PIC method, especially under near far conditions. However, when an antenna array is used at the base station, and the array output is fed into PIC processing, the two PIC methods perform almost the same. Therefore, accounting to the frame structure of WCDMA, a space-temporal interference cancellation scheme including pilot-bits assisted LMS-DRMTA algorithm and soft-decision averaging amplitude estimation PIC is proposed for the uplink of WCDMA system. The overall scheme is characterized by low complexity and strong robustness.
This paper simplifies the adaptive parallel interference cancellation (PIC) scheme into a ne method named soft-decision variant averaging amplitude estimation PIC technology. Relative to the adaptive PIC, the new method cuts down large amount of computational complexity, furthermore, it has better robustness than the adaptive PIC method. The simulations indicate that when a single sensor is used at the base station, the new method performs worse than the adaptive PIC method, especially under near far conditions. However, when an antenna array is used at the base station, and the array output is fed into PIC processing, the two PIC methods perform almost the same. Therefore, accounting to the frame structure of WCDMA, a space-temporal interference cancellation scheme including pilot-bits assisted LMS-DRMTA algorithm and soft-decision averaging amplitude estimation PIC is proposed for the uplink of WCDMA system. The overall scheme is characterized by low complexity and strong robustness.
2002, 24(8): 1109-1112.
Abstract:
This paper discusses the bounds on the probability of success in impersonation and substitution attack by malicious groups of receivers for multiple authentication codes with multi-receiver, and gives out the least-size of the secret key space that the sender and the receivers must have in hand to ensure the multiple authertication codes with multi-receiver being under security level and presents also its construting method.
This paper discusses the bounds on the probability of success in impersonation and substitution attack by malicious groups of receivers for multiple authentication codes with multi-receiver, and gives out the least-size of the secret key space that the sender and the receivers must have in hand to ensure the multiple authertication codes with multi-receiver being under security level and presents also its construting method.
2002, 24(8): 1113-1119.
Abstract:
This paper proposes a new flexible method of the beam shaping based on superposition principle and the scanning principle of phased array antenna. We designed a 145cm*48cm array composed of microstrip patch elements with the wavelength of 24cm. In the azimuth direction, the pattern of this array has 23 half-power beam width. According to the principle of the synthetic aperture, the azimuth spatial resolution of the strip SAR is improved dramatically with wide exam. In this paper, the wide beam antenna array is used as the antenna of an airborne SAR with ultrahigh azimuth resolution. The parameters of the antenna and the SAR system are calculated and are compared between the strip-mapping SAR and the Spotlight SAR.
This paper proposes a new flexible method of the beam shaping based on superposition principle and the scanning principle of phased array antenna. We designed a 145cm*48cm array composed of microstrip patch elements with the wavelength of 24cm. In the azimuth direction, the pattern of this array has 23 half-power beam width. According to the principle of the synthetic aperture, the azimuth spatial resolution of the strip SAR is improved dramatically with wide exam. In this paper, the wide beam antenna array is used as the antenna of an airborne SAR with ultrahigh azimuth resolution. The parameters of the antenna and the SAR system are calculated and are compared between the strip-mapping SAR and the Spotlight SAR.
2002, 24(8): 1120-1125.
Abstract:
A stacked double-patch and four-layer substrate microstrip antenna with the capacitance compensation probe feed is designed by combining the experimental formulae and the full-wave method. The relative impedance bandwidth of this microstrip antenna reaches up to 12.26% in the frequency band between 995MHz and 1125MHz under the condition that SWR is less than 1.5. In addition, a 2*16 array composed by this kind of microstrip antenna is presented and the experimental results of the SWR are given too. Finally, the arrangement of elements in the antenna array and the experimental results of the mutual coupling between elements are given.
A stacked double-patch and four-layer substrate microstrip antenna with the capacitance compensation probe feed is designed by combining the experimental formulae and the full-wave method. The relative impedance bandwidth of this microstrip antenna reaches up to 12.26% in the frequency band between 995MHz and 1125MHz under the condition that SWR is less than 1.5. In addition, a 2*16 array composed by this kind of microstrip antenna is presented and the experimental results of the SWR are given too. Finally, the arrangement of elements in the antenna array and the experimental results of the mutual coupling between elements are given.
2002, 24(8): 1126-1130.
Abstract:
Considering the effect of the logitudinal uniform magnetic field, the microwave radiation produced by the interaction of a relativistic electron beam with a annular plasma is examined by use of the liner theory. In this paper the applied field approach is used to derive the dispersion relationship. Analyzed the different plasma density, position, thickness, and field intensity influence to the beam-wave interactions in plasma Cerenkov maser. Finally, the curves and dispersion relationships about every parameter to influence the increase rates of linear space are given out.
Considering the effect of the logitudinal uniform magnetic field, the microwave radiation produced by the interaction of a relativistic electron beam with a annular plasma is examined by use of the liner theory. In this paper the applied field approach is used to derive the dispersion relationship. Analyzed the different plasma density, position, thickness, and field intensity influence to the beam-wave interactions in plasma Cerenkov maser. Finally, the curves and dispersion relationships about every parameter to influence the increase rates of linear space are given out.
2002, 24(8): 1134-1138.
Abstract:
Most algorithms use pseudorandom sequences as watermarks, whose presence are determined according to its correlation with original sequence. In this paper an identifier (ID) watermarking algorithm is proposed, which has the characteristics of error-correct, high redundance and adaptive watermark retrieval. Experimental results demonstrate that it is effective and feasible.
Most algorithms use pseudorandom sequences as watermarks, whose presence are determined according to its correlation with original sequence. In this paper an identifier (ID) watermarking algorithm is proposed, which has the characteristics of error-correct, high redundance and adaptive watermark retrieval. Experimental results demonstrate that it is effective and feasible.
2002, 24(8): 1139-1142.
Abstract:
In this paper, a novel analysis of feedforward linearizing power amplifier is presented. Experimental results are reported for a CDMA IS-95 base station feedforward linearizing amplifier, which demonstrates a minimum of 23dB intermodulation distortion suppression when the amplifier s gain is 47 dB and continue wave output power is 60W.
In this paper, a novel analysis of feedforward linearizing power amplifier is presented. Experimental results are reported for a CDMA IS-95 base station feedforward linearizing amplifier, which demonstrates a minimum of 23dB intermodulation distortion suppression when the amplifier s gain is 47 dB and continue wave output power is 60W.
2002, 24(8): 1143-1147.
Abstract:
Real-time Imager can provide Synthetic Aperture Radar(SAR) image in real-time mode which is significant for airborne SAR applications such as real-time monitoring and battle reconnaissance. A SAR real-time imager usually implements SAR imaging algorithms with high-speed DSP system. This paper describes a high-speed DSP system based on ADSP21062 to realize azimuth processing with range-Doppler algorithm, consisting of range migration correction and azimuth compression. 8 ADSP21062s are organized in 4 parallel processing blocks in this system achieving a processing speed of 960MFLOP. Elaborate software programming ensures a high efficient utilization of hardware. Experimental simulation and field flight indicate this system is successful. The principle architecture, hardware implementation and software design are presented in this paper in details.
Real-time Imager can provide Synthetic Aperture Radar(SAR) image in real-time mode which is significant for airborne SAR applications such as real-time monitoring and battle reconnaissance. A SAR real-time imager usually implements SAR imaging algorithms with high-speed DSP system. This paper describes a high-speed DSP system based on ADSP21062 to realize azimuth processing with range-Doppler algorithm, consisting of range migration correction and azimuth compression. 8 ADSP21062s are organized in 4 parallel processing blocks in this system achieving a processing speed of 960MFLOP. Elaborate software programming ensures a high efficient utilization of hardware. Experimental simulation and field flight indicate this system is successful. The principle architecture, hardware implementation and software design are presented in this paper in details.
2002, 24(8): 1148-1152.
Abstract:
The one-dimensional Fresnel zone phase correcting principle can be applied in a cylindrical surface to constructed a new type of point source feeding lens antenna. In this paper, the auxiliary source method is used to evaluate the focused fields of this new lens antenna under arbitrary plane wave incidence, placing emphasis on the analysis of the paraxial scanning performance and frequency properties of the focused fields.
The one-dimensional Fresnel zone phase correcting principle can be applied in a cylindrical surface to constructed a new type of point source feeding lens antenna. In this paper, the auxiliary source method is used to evaluate the focused fields of this new lens antenna under arbitrary plane wave incidence, placing emphasis on the analysis of the paraxial scanning performance and frequency properties of the focused fields.
2002, 24(8): 1131-1133.
Abstract:
In this paper, it is pointed out by a counterexample that the condition of the freshness rule on BAN logic which in the paper The Investigation of the Freshness in BAN Logic written by Song Ronggong, et al. is so strict that it regards possibly a secure protocol as an insecure protocol.
In this paper, it is pointed out by a counterexample that the condition of the freshness rule on BAN logic which in the paper The Investigation of the Freshness in BAN Logic written by Song Ronggong, et al. is so strict that it regards possibly a secure protocol as an insecure protocol.
