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1995 Vol. 17, No. 6
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1995, 17(6): 561-568.
Abstract:
new still-picture compression coding algorithm, VQ + DPCM + DCT algorithm, is proposed. The performance of JPEG baseline system and VQ + DPCM + DCT algorithm is compared. Experimental results show that the aew algorithm is very efficient.
new still-picture compression coding algorithm, VQ + DPCM + DCT algorithm, is proposed. The performance of JPEG baseline system and VQ + DPCM + DCT algorithm is compared. Experimental results show that the aew algorithm is very efficient.
1995, 17(6): 569-576.
Abstract:
A new method is presented to design a rotated Barnes-Wall lattice based vector quantizer (LVQ). The construction method of the LVQ and its fast quantizing algorithm are described, then the gain-shape vector quantizer (GSLVQ) with LVQ as shape VQ is discussed. Finally the GSLVQ is used in image-sequence coding and good experimental results are obtained.
A new method is presented to design a rotated Barnes-Wall lattice based vector quantizer (LVQ). The construction method of the LVQ and its fast quantizing algorithm are described, then the gain-shape vector quantizer (GSLVQ) with LVQ as shape VQ is discussed. Finally the GSLVQ is used in image-sequence coding and good experimental results are obtained.
1995, 17(6): 577-584.
Abstract:
The current Markov random field models for image restoration and segmentation are discussed. A configuration of the image field is regarded as an optimal estimate of the original scene when its energy is the lowest. However, the lowest energy configuration does not correspond to the scene on the edges, which results in errors of restoration or segmentation. Improvements of the model are made and a relaxation algorithm based on the improved model is presented using edge information obtained by a coarse-to-fine procedure. Some examples are also presented on the application of the algorithm to restoration of noisy images.
The current Markov random field models for image restoration and segmentation are discussed. A configuration of the image field is regarded as an optimal estimate of the original scene when its energy is the lowest. However, the lowest energy configuration does not correspond to the scene on the edges, which results in errors of restoration or segmentation. Improvements of the model are made and a relaxation algorithm based on the improved model is presented using edge information obtained by a coarse-to-fine procedure. Some examples are also presented on the application of the algorithm to restoration of noisy images.
1995, 17(6): 585-590.
Abstract:
Based on a joint time-frequency two dimensional processing, this paper proposes a method for the detection and imaging of moving targets with SAR by using Wigner-Ville Distribution (WVD). It is a parameter estimation method to generate a high resolution image. The problems of WVD in dealing with multipoint targets and extent targets are also discussed. The computer simulation results illustrate its availability.
Based on a joint time-frequency two dimensional processing, this paper proposes a method for the detection and imaging of moving targets with SAR by using Wigner-Ville Distribution (WVD). It is a parameter estimation method to generate a high resolution image. The problems of WVD in dealing with multipoint targets and extent targets are also discussed. The computer simulation results illustrate its availability.
1995, 17(6): 591-598.
Abstract:
The problem of radar target recognition based on a radial basis function network is discussed. On the basis of analyzing the features of one-dimensional range profile, an effective method is proposed, which performs amplitude average of the range profiles to obtain more stable patterns. After pointing out the limitedness of traditional experimental formula, this paper also gives a method of estimating the shape parameter of a Guassian kernel function based on the spacial distribution of training samples.It is shown from theoretical analysis and experimental results of rotating platform imaging based on data acquired in a microwave anechoic chamber that the method proposed in this paper is promissing in the application of radar target recognition.
The problem of radar target recognition based on a radial basis function network is discussed. On the basis of analyzing the features of one-dimensional range profile, an effective method is proposed, which performs amplitude average of the range profiles to obtain more stable patterns. After pointing out the limitedness of traditional experimental formula, this paper also gives a method of estimating the shape parameter of a Guassian kernel function based on the spacial distribution of training samples.It is shown from theoretical analysis and experimental results of rotating platform imaging based on data acquired in a microwave anechoic chamber that the method proposed in this paper is promissing in the application of radar target recognition.
1995, 17(6): 599-606.
Abstract:
This paper proposes a BDML estimator used for low angle tracking in conventional radar. In order to improve estimation performance for target direction, some signal processing methods are introduced, such as frequency diversity (multi-frequency processing), beam-space expansion, utilization of information a priari, snapshot data preprocessing and data filtering after BDML estimation etc. Finally, computer simulations are provided for target tracking.
This paper proposes a BDML estimator used for low angle tracking in conventional radar. In order to improve estimation performance for target direction, some signal processing methods are introduced, such as frequency diversity (multi-frequency processing), beam-space expansion, utilization of information a priari, snapshot data preprocessing and data filtering after BDML estimation etc. Finally, computer simulations are provided for target tracking.
1995, 17(6): 607-612.
Abstract:
This paper discribes a signal processing system in a Pulse Doppler (PD) radar. It mainly consists of a velocity tracking loop and a digital signal processing auxiliary channel. With many signal processing techniques, the system sucess-fully resolves the signal detection and tracking at low SNR and the interference identification and rejection. The idea of system design is introduced in details. Finally, some simulation and expreimental results are presented.
This paper discribes a signal processing system in a Pulse Doppler (PD) radar. It mainly consists of a velocity tracking loop and a digital signal processing auxiliary channel. With many signal processing techniques, the system sucess-fully resolves the signal detection and tracking at low SNR and the interference identification and rejection. The idea of system design is introduced in details. Finally, some simulation and expreimental results are presented.
1995, 17(6): 613-617.
Abstract:
The test theorem of 2-D discrete Hurwitz polynomials is proposed. Different from the algebraic methods for the polynomials, the approach of this paper is to list table for complex variable coefficients directly, then to test zero existence for the polynomials with the theorem of this paper. The test proceedure is greatly simplified, and reduces the computations, for it need not to test all x in real domain [-1, 1] point by point and will not meet the rational polynomials. To determine whether they are 2-D discrete Hurwitz polynomialsneeds only finite computations.
The test theorem of 2-D discrete Hurwitz polynomials is proposed. Different from the algebraic methods for the polynomials, the approach of this paper is to list table for complex variable coefficients directly, then to test zero existence for the polynomials with the theorem of this paper. The test proceedure is greatly simplified, and reduces the computations, for it need not to test all x in real domain [-1, 1] point by point and will not meet the rational polynomials. To determine whether they are 2-D discrete Hurwitz polynomialsneeds only finite computations.
1995, 17(6): 618-622.
Abstract:
De Bruijn sequences are highly important nonlinear shift register sequences. This paper presents a new algorithm for the generation of k-ary de Bruijn sequences by juxtaposing the periodic reductions of the necklaces. Its each step produces a string of elements instead of one element. Hence the algorithm reduces the lime of operation, and accelerates the speed of generation.
De Bruijn sequences are highly important nonlinear shift register sequences. This paper presents a new algorithm for the generation of k-ary de Bruijn sequences by juxtaposing the periodic reductions of the necklaces. Its each step produces a string of elements instead of one element. Hence the algorithm reduces the lime of operation, and accelerates the speed of generation.
1995, 17(6): 623-630.
Abstract:
The laws of reflection and refraction of harmonic waves at a plane interface between linear and nonlinear media are carefully analysed. The exact expressions of the reflective and transmissive fields are derived. The further discussions are made to the fields under the conditions of vertical incidence and phase-matching.
The laws of reflection and refraction of harmonic waves at a plane interface between linear and nonlinear media are carefully analysed. The exact expressions of the reflective and transmissive fields are derived. The further discussions are made to the fields under the conditions of vertical incidence and phase-matching.
1995, 17(6): 638-642.
Abstract:
This paper provides a new architecture of neural network, called Loop Architecture Neural Network (LANN), and its learning rules. One of its distinguished features from other network, such as Hopfield and bidirectional assiociative memories, is that it can perform the associative memory among multiple categories. Analysis and simulated results have proved that it is an effective network with excellent convergence.
This paper provides a new architecture of neural network, called Loop Architecture Neural Network (LANN), and its learning rules. One of its distinguished features from other network, such as Hopfield and bidirectional assiociative memories, is that it can perform the associative memory among multiple categories. Analysis and simulated results have proved that it is an effective network with excellent convergence.
1995, 17(6): 643-646.
Abstract:
The blind equalization technique for MPSK signals is analysed and studied. A new blind equalization algorithm and the variable step-size blind equalization algorithm are presented. Computer simulations indicate that the new blind equalization algorithm and its improved form have a good convergence performance, so the communication systems can work continuously and do not require to be trained periodically.
The blind equalization technique for MPSK signals is analysed and studied. A new blind equalization algorithm and the variable step-size blind equalization algorithm are presented. Computer simulations indicate that the new blind equalization algorithm and its improved form have a good convergence performance, so the communication systems can work continuously and do not require to be trained periodically.
1995, 17(6): 647-651.
Abstract:
This paper proposes the design scheme of back-loaded pulsed antenna. A sector antenna and a rectangular antenna are made on the basis of the method. Based on the measured radar data, the differences among the above-mentioned new scheme, a non-reflecting continuously resistive loaded cross dipole antenna and a double diamond antenna are discussed. It results in the confirmation of the superiority of the back-loaded design scheme.
This paper proposes the design scheme of back-loaded pulsed antenna. A sector antenna and a rectangular antenna are made on the basis of the method. Based on the measured radar data, the differences among the above-mentioned new scheme, a non-reflecting continuously resistive loaded cross dipole antenna and a double diamond antenna are discussed. It results in the confirmation of the superiority of the back-loaded design scheme.
1995, 17(6): 652-655.
Abstract:
The complex astigmatic wave is used to ananlyze the electromagnetic scattering characters of ocean surface varying with time. Some numerical results are compared with experimental data, and some factors, such as incident angle, polarization and frequency, are investigated which influence on electromagnetic scattering characters of ocean surface.
The complex astigmatic wave is used to ananlyze the electromagnetic scattering characters of ocean surface varying with time. Some numerical results are compared with experimental data, and some factors, such as incident angle, polarization and frequency, are investigated which influence on electromagnetic scattering characters of ocean surface.
1995, 17(6): 656-660.
Abstract:
As a new current-mode technique, switched current has been in a forward position of current-mode analog signal processing. This paper submitted a signal-flaw graph analysing method for switched current networks by introducing concepts of odd mirror and even mirror, and applied them to analyse the switched current filter. The result of computer simulation verified the reliability and feasibility of the method.
As a new current-mode technique, switched current has been in a forward position of current-mode analog signal processing. This paper submitted a signal-flaw graph analysing method for switched current networks by introducing concepts of odd mirror and even mirror, and applied them to analyse the switched current filter. The result of computer simulation verified the reliability and feasibility of the method.
1995, 17(6): 661-664.
Abstract:
The theory of plate and shell is used to analyze the problem of electrostatic bonding of glass with silicon plate. This problem is to find Out the relation between the bending stress of silicon plate and the electrostatic force of interface. The conditions of successful bonding are found. A formula among the distance d between the two surfaces and the rigidity D, the bending deflection and the voltage V is derived, and a series of experiments to verify it is performed.
The theory of plate and shell is used to analyze the problem of electrostatic bonding of glass with silicon plate. This problem is to find Out the relation between the bending stress of silicon plate and the electrostatic force of interface. The conditions of successful bonding are found. A formula among the distance d between the two surfaces and the rigidity D, the bending deflection and the voltage V is derived, and a series of experiments to verify it is performed.
1995, 17(6): 631-637.
Abstract:
The international trends of the development in the nanotechnology field is introduced. On the basis of the research works of a major project and a key project supported by the NSFC during the period of 1990-1995, the recent development on the field of nanotechnology is described briefly, especially at the outstanding work on single-atom-operation by the Open Laboratory of Vacuum Physics, Academia Sinica.
The international trends of the development in the nanotechnology field is introduced. On the basis of the research works of a major project and a key project supported by the NSFC during the period of 1990-1995, the recent development on the field of nanotechnology is described briefly, especially at the outstanding work on single-atom-operation by the Open Laboratory of Vacuum Physics, Academia Sinica.
