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2003 Vol. 25, No. 12
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2003, 25(12): 1585-1590.
Abstract:
This paper describes how to combine PCNN(Pulse Coupled Neural Network) with fuzzy algorithm to reduce the noise of four-level images. Meanwhile, the image noise-reduciug algorithm based on the fuzzy PCNN is brought forward. The results of computer simulations show that noisy four-level images can be restored efficiently by using fuzzy PCNN and visual effects of restoration images by using fuzzy PCNN are much better than those by using two usual image noising-reducing methods, the median filter and the mean filter. Noise-reducing of the four-level images plays an important role in the medical image processing and the military image processing, Therefore, this paper contributes to both the theoretical researches on PCNN and the applications of PCNN.
This paper describes how to combine PCNN(Pulse Coupled Neural Network) with fuzzy algorithm to reduce the noise of four-level images. Meanwhile, the image noise-reduciug algorithm based on the fuzzy PCNN is brought forward. The results of computer simulations show that noisy four-level images can be restored efficiently by using fuzzy PCNN and visual effects of restoration images by using fuzzy PCNN are much better than those by using two usual image noising-reducing methods, the median filter and the mean filter. Noise-reducing of the four-level images plays an important role in the medical image processing and the military image processing, Therefore, this paper contributes to both the theoretical researches on PCNN and the applications of PCNN.
2003, 25(12): 1591-1597.
Abstract:
In this paper, a novel image retrieval algorithm based on feature element is proposed. Compared with feature vectors, feature elements tend to represent visual meanings of the image according to subjective perception of human beings. Based on feature elements, the similarity between images is defined which is measured by the distant between feature elements. Retrieval experiments show that image retrieval based on feature elements can retrieve images which are more accordant with visual perception of human beings.
In this paper, a novel image retrieval algorithm based on feature element is proposed. Compared with feature vectors, feature elements tend to represent visual meanings of the image according to subjective perception of human beings. Based on feature elements, the similarity between images is defined which is measured by the distant between feature elements. Retrieval experiments show that image retrieval based on feature elements can retrieve images which are more accordant with visual perception of human beings.
2003, 25(12): 1598-1602.
Abstract:
In this paper, a new method of image compare search engine for fractal coding is proposed, namely using image topology characteristic of Iterative Function System (IFS) and applying to image deposit and retrieval. However, the image produces a lot of data by fractal coding and needs an effective method to retrieval, so this paper is based on Fisher discriminant function to estimate images similarity. Experiment shows image compare search engine can get exactly similar image of query image, it also has been testified better for tolerate-error and can effectively improve adaptivity in practice of image compare search engine.
In this paper, a new method of image compare search engine for fractal coding is proposed, namely using image topology characteristic of Iterative Function System (IFS) and applying to image deposit and retrieval. However, the image produces a lot of data by fractal coding and needs an effective method to retrieval, so this paper is based on Fisher discriminant function to estimate images similarity. Experiment shows image compare search engine can get exactly similar image of query image, it also has been testified better for tolerate-error and can effectively improve adaptivity in practice of image compare search engine.
2003, 25(12): 1603-1611.
Abstract:
This paper introduces a new multiresolution image recognition method. At first, it makes multi-wavelet division over the image, organizes the corresponding components of different resolution into a vector. Then, makes a Fisher transform over the vectors. Recognition is based on the sum of the absolute distance between the vector of the unknown object and the vector of the template or based on the relative distance which is defined as the absolute distance between the vector of the unknown object and that of the template divided by the distance between the vectors of the corresponding templates in the Fisher transformed domain. Because the recognition is mainly dependent on the low frequency component, the method is insensitive noise pixels in the images. Because the recognition procedure has included multiresolution recognizing computation, the right rate of recognition is in sensitive to the dimension size of the image in some degree. The practice of the method proves that the right rate of recognition is very high and the robustness of the method is strong.
This paper introduces a new multiresolution image recognition method. At first, it makes multi-wavelet division over the image, organizes the corresponding components of different resolution into a vector. Then, makes a Fisher transform over the vectors. Recognition is based on the sum of the absolute distance between the vector of the unknown object and the vector of the template or based on the relative distance which is defined as the absolute distance between the vector of the unknown object and that of the template divided by the distance between the vectors of the corresponding templates in the Fisher transformed domain. Because the recognition is mainly dependent on the low frequency component, the method is insensitive noise pixels in the images. Because the recognition procedure has included multiresolution recognizing computation, the right rate of recognition is in sensitive to the dimension size of the image in some degree. The practice of the method proves that the right rate of recognition is very high and the robustness of the method is strong.
2003, 25(12): 1612-1616.
Abstract:
A digital watermarking sharing algorithm based on vector secret sharing scheme is presented, which applies the thought of vector sharing to digital watermarking. The algorithm disturbs both the original watermark and the sharing block watermark before hiding the original watermark. The sharing processing has the effect of disturbing too. So the algorithm has highly security. Experimental results show the algorithm has a good effect of hiding and anti-cutting.
A digital watermarking sharing algorithm based on vector secret sharing scheme is presented, which applies the thought of vector sharing to digital watermarking. The algorithm disturbs both the original watermark and the sharing block watermark before hiding the original watermark. The sharing processing has the effect of disturbing too. So the algorithm has highly security. Experimental results show the algorithm has a good effect of hiding and anti-cutting.
2003, 25(12): 1617-1621.
Abstract:
A new semi-blinding watermarking algorithm in wavelet domain is proposed in this paper. The original image is first decomposed in wavelet domain, then the feature points are extracted from the lowest approximation with the scale interaction model for feature detection and the image feature tree in wavelet domain is created corresponding to the feature points. The binary watermark bits are embedded in all the nodes of the feature tree. Watermark extraction only needs the feature points position but not the original image. Since the watermark bits are inserted into the features of image, it is robust to common image processing, especially to the lossy compression such as JPEG, JPEG2000 and Gaussian noise. It belongs to the second generation watermarking schemes.
A new semi-blinding watermarking algorithm in wavelet domain is proposed in this paper. The original image is first decomposed in wavelet domain, then the feature points are extracted from the lowest approximation with the scale interaction model for feature detection and the image feature tree in wavelet domain is created corresponding to the feature points. The binary watermark bits are embedded in all the nodes of the feature tree. Watermark extraction only needs the feature points position but not the original image. Since the watermark bits are inserted into the features of image, it is robust to common image processing, especially to the lossy compression such as JPEG, JPEG2000 and Gaussian noise. It belongs to the second generation watermarking schemes.
2003, 25(12): 1622-1627.
Abstract:
SAR/ISAR image processing involves a 2D Fourier transform that produce high intensity sidelobes which obscure low intensity scatters in the image. Although sidolobitt can be reduced using parametric windows, the image resolution becomes worse. Apodization technique can reduce sidelobe levels while maintaining the image resolution. In this paper, based on the analysis of apodization algorithm, a modified apodization method is presented via stronger constraint. The modified method has higher resolution and lower sidelobe levels than the original method. The correctness of this method is proved by using a real ISAR image.
SAR/ISAR image processing involves a 2D Fourier transform that produce high intensity sidelobes which obscure low intensity scatters in the image. Although sidolobitt can be reduced using parametric windows, the image resolution becomes worse. Apodization technique can reduce sidelobe levels while maintaining the image resolution. In this paper, based on the analysis of apodization algorithm, a modified apodization method is presented via stronger constraint. The modified method has higher resolution and lower sidelobe levels than the original method. The correctness of this method is proved by using a real ISAR image.
2003, 25(12): 1628-1633.
Abstract:
NMTI is a noncoherent method to detect moving target through relative range displacement between sequent radar echo signals. It can be used in wideband radar systems for moving target detection and clutter suppression effectively. In this paper, ideal rectangle and Gaussian shape pulse act as radar echo signal model. Through simulation research, application of NMTI method in wideband radar systems is discussed in detail.
NMTI is a noncoherent method to detect moving target through relative range displacement between sequent radar echo signals. It can be used in wideband radar systems for moving target detection and clutter suppression effectively. In this paper, ideal rectangle and Gaussian shape pulse act as radar echo signal model. Through simulation research, application of NMTI method in wideband radar systems is discussed in detail.
2003, 25(12): 1634-1640.
Abstract:
The theory and method of designing radar signal with MAC-sequence-code are systematically studied in this paper. Both theoretic analysis and simulation results show that MAC-sequence is a binary sequence with ideal correlation property and ability of anti-shelter effect. MAC-sequence-coded radar signal is a practical signal with good LPI feature and can be used to measure the distance and velocity unambiguously.
The theory and method of designing radar signal with MAC-sequence-code are systematically studied in this paper. Both theoretic analysis and simulation results show that MAC-sequence is a binary sequence with ideal correlation property and ability of anti-shelter effect. MAC-sequence-coded radar signal is a practical signal with good LPI feature and can be used to measure the distance and velocity unambiguously.
2003, 25(12): 1641-1646.
Abstract:
Based on range migration imaging technique, this paper investigates ground penetrating radar three dimension imaging algorithm under near field condition, discusses the back propagation algorithm at the same time. Theoretical analysis shows that near field 3-D range migration imaging technique can reduce computational complexity in much degree by contrast with back propagation algorithm. Finally, through processing the experimental data, 3-D images of underground objects are obtained. The results validate the correctness of the near field 3-D range migration imaging algorithm and its capability at the aspect of real time processing.
Based on range migration imaging technique, this paper investigates ground penetrating radar three dimension imaging algorithm under near field condition, discusses the back propagation algorithm at the same time. Theoretical analysis shows that near field 3-D range migration imaging technique can reduce computational complexity in much degree by contrast with back propagation algorithm. Finally, through processing the experimental data, 3-D images of underground objects are obtained. The results validate the correctness of the near field 3-D range migration imaging algorithm and its capability at the aspect of real time processing.
2003, 25(12): 1647-1652.
Abstract:
An algorithm of caption detection in news video is proposed in this paper. It makes use of space and time characters of the captions appearing in the video. On the basis of shot boundary detection, this method applies morphological operation and different filter strategies according to different cases. It achieves good results by experiments using MPEG-7 video testing data, especially caption detection in the case of gradual transition and heavy noises on the background.
An algorithm of caption detection in news video is proposed in this paper. It makes use of space and time characters of the captions appearing in the video. On the basis of shot boundary detection, this method applies morphological operation and different filter strategies according to different cases. It achieves good results by experiments using MPEG-7 video testing data, especially caption detection in the case of gradual transition and heavy noises on the background.
2003, 25(12): 1653-1657.
Abstract:
In order to improve the ability of chaotic system detecting weak periodic pulse signals, this paper proposes the detecting scheme uniting sampling integral with chaotic sys-tem. The simulation results indicate that the united detecting scheme precedes the detecting method without sampling integral under the same experimental background. Because occu-pied space ratio of the periodic pulse signals diminishes, the detected minimum amplitude increases. The intension decrease of input noise can simplify the critical phase state of detecting system.
In order to improve the ability of chaotic system detecting weak periodic pulse signals, this paper proposes the detecting scheme uniting sampling integral with chaotic sys-tem. The simulation results indicate that the united detecting scheme precedes the detecting method without sampling integral under the same experimental background. Because occu-pied space ratio of the periodic pulse signals diminishes, the detected minimum amplitude increases. The intension decrease of input noise can simplify the critical phase state of detecting system.
2003, 25(12): 1658-1663.
Abstract:
This paper presents a detailed method on constructing multi-scaling functions with fractal interpolation functions, then calculates that det H0(z) and det H0(-z) have no common roots, and obtains F0(z) the dual low pass multi-filter of H0(Z) with the perfect reconstruction condition of biorthogonal low pass multi-filters. In order to construct the dual low pass multi-filter of H0(z) with higher approximation order, the two-scale similarity transform is taken for H0(z), then and its dual H0new t(z) is obtained. After applying corre-sponding inverse transform to F0new(z), the dual low pass multi-filter of H0(z) with higher approximation order is achieved.
This paper presents a detailed method on constructing multi-scaling functions with fractal interpolation functions, then calculates that det H0(z) and det H0(-z) have no common roots, and obtains F0(z) the dual low pass multi-filter of H0(Z) with the perfect reconstruction condition of biorthogonal low pass multi-filters. In order to construct the dual low pass multi-filter of H0(z) with higher approximation order, the two-scale similarity transform is taken for H0(z), then and its dual H0new t(z) is obtained. After applying corre-sponding inverse transform to F0new(z), the dual low pass multi-filter of H0(z) with higher approximation order is achieved.
A New Method for Mitigating the Effect of NLOS Propagation in the TOA and AOA Hybrid Location System
2003, 25(12): 1664-1668.
Abstract:
Based on the relationship between the errors of the Circular Lines of Position (LOPs) and the straight LOPs and that of the measured parameters, a hybrid locating system in which the Time Of Arrival (TOA) and the Angle Of Arrival (AOA) measured by the closest Base Station (BS) are combined is presented to mitigate the effect of Non-Line-Of-Sight (NLOS) propagation in this paper. In order to reduce the feasible region of the Mobile Station (MS) and to improve the accuracy of the location estimation, the restrictions that TOA estimates are always greater than the true TOA values and the angle spreads are always smaller than the maximum angle spread determined by the Geometrically Based Single Bounce Circular Model (GBSBCM) are used. Its effectiveness is verified by the simulation.
Based on the relationship between the errors of the Circular Lines of Position (LOPs) and the straight LOPs and that of the measured parameters, a hybrid locating system in which the Time Of Arrival (TOA) and the Angle Of Arrival (AOA) measured by the closest Base Station (BS) are combined is presented to mitigate the effect of Non-Line-Of-Sight (NLOS) propagation in this paper. In order to reduce the feasible region of the Mobile Station (MS) and to improve the accuracy of the location estimation, the restrictions that TOA estimates are always greater than the true TOA values and the angle spreads are always smaller than the maximum angle spread determined by the Geometrically Based Single Bounce Circular Model (GBSBCM) are used. Its effectiveness is verified by the simulation.
2003, 25(12): 1669-1675.
Abstract:
Forward link packet data service scheduling algorithm is extensively researched and it is indicated that there is an exclusive relationship between the data throughput and fairness. Under certain fairness criteria, the closer the data throughput cumulative distri-bution functions to the fairness criteria, the higher the data throughput. Based on this judgment, here a new scheduling algorithm is proposed, which can change the relation-ship between the data throughput and fairness criteria through adjusting the parameters. Furthermore, with a view on the tradeoff between the data throughput and fairness, the asymptotic optimal approximation can be found quite easily.
Forward link packet data service scheduling algorithm is extensively researched and it is indicated that there is an exclusive relationship between the data throughput and fairness. Under certain fairness criteria, the closer the data throughput cumulative distri-bution functions to the fairness criteria, the higher the data throughput. Based on this judgment, here a new scheduling algorithm is proposed, which can change the relation-ship between the data throughput and fairness criteria through adjusting the parameters. Furthermore, with a view on the tradeoff between the data throughput and fairness, the asymptotic optimal approximation can be found quite easily.
2003, 25(12): 1676-1681.
Abstract:
According to the characteristics of Assured Forwarding (AF) aggregated flows of Differentiated Services(DiffServ), a new scheduling algorithm, named Fair Weighted Round Robin(FWRR) is proposed. FWRR is a work-conserving round robin scheduling algorithm for variable size packets. It has a very low implementation complexity of O(1). Simulation results and mathematic analyses show that FWRR can make each queue at least occupy a minimum reserved bandwidth and share some extra bandwidth proportionally. Therefore, FWRR is a suitable scheduling algorithm for the AF flows of DiffServ.
According to the characteristics of Assured Forwarding (AF) aggregated flows of Differentiated Services(DiffServ), a new scheduling algorithm, named Fair Weighted Round Robin(FWRR) is proposed. FWRR is a work-conserving round robin scheduling algorithm for variable size packets. It has a very low implementation complexity of O(1). Simulation results and mathematic analyses show that FWRR can make each queue at least occupy a minimum reserved bandwidth and share some extra bandwidth proportionally. Therefore, FWRR is a suitable scheduling algorithm for the AF flows of DiffServ.
2003, 25(12): 1682-1687.
Abstract:
An implementation of the Model Based Parameter Estimation(MBPE) tech-nique is presented for obtaining the RCS frequency response of arbitrarily shaped Perfect Electric Conductor (PEC) bodies. The electric current is expanded in a Taylor series or Pade rational function around the frequency of interest, thus the -scattering field is obtained over the bandwidth. Rational function fitting model is also used for the interpolation of RCS in both spatial domain and frequency domain. A good agreement can be seen between MBPE and the exact solution, and the computational burden is significantly reduced.
An implementation of the Model Based Parameter Estimation(MBPE) tech-nique is presented for obtaining the RCS frequency response of arbitrarily shaped Perfect Electric Conductor (PEC) bodies. The electric current is expanded in a Taylor series or Pade rational function around the frequency of interest, thus the -scattering field is obtained over the bandwidth. Rational function fitting model is also used for the interpolation of RCS in both spatial domain and frequency domain. A good agreement can be seen between MBPE and the exact solution, and the computational burden is significantly reduced.
2003, 25(12): 1688-1694.
Abstract:
A simulated computation method is developed by theoretical analysis and de-duction to compute the gap impedance varying with frequency of output cavity loaded with a filter. Meanwhile, a practical example is used to show that how to compute the frequency and the loaded quality factor of the output cavity loaded with waveguide by this simulated computation method and the computed result is verified to be reasonable in theory. Finally, a output cavity loaded with a filter is computed and the computed result is analyzed and compared with cold test data in order to conform the reliability of this simulated computation method.
A simulated computation method is developed by theoretical analysis and de-duction to compute the gap impedance varying with frequency of output cavity loaded with a filter. Meanwhile, a practical example is used to show that how to compute the frequency and the loaded quality factor of the output cavity loaded with waveguide by this simulated computation method and the computed result is verified to be reasonable in theory. Finally, a output cavity loaded with a filter is computed and the computed result is analyzed and compared with cold test data in order to conform the reliability of this simulated computation method.
2003, 25(12): 1703-1708.
Abstract:
After analyzing several abuses of transporting data service in existing WCDMA system, this paper presents a UL power control algorithm and relevant QoS guarantee. The new algorithm utilized some characteristic of data services, such as its controllable transport speed and low delay need. It is verified by emulator analysis that this algorithm can increase efficiently the utility factor of the system resource. At the same time, it also can improve the quality of communication when the system load is heavy and assure higher ratio of access when a new user try to access to system.
After analyzing several abuses of transporting data service in existing WCDMA system, this paper presents a UL power control algorithm and relevant QoS guarantee. The new algorithm utilized some characteristic of data services, such as its controllable transport speed and low delay need. It is verified by emulator analysis that this algorithm can increase efficiently the utility factor of the system resource. At the same time, it also can improve the quality of communication when the system load is heavy and assure higher ratio of access when a new user try to access to system.
2003, 25(12): 1709-1713.
Abstract:
In order to support cooperative work in enterprise environment, voice tool should provide flexible floor control mode. Because mixed audio is not clear in existing voice tools, they have freezing floor control mode only where members talk by turns which limits the free discussing among group. In the paper, a new mixed audio algorithm, which improves voice quality, adopted by voice tool ENVoice (Enterprise Network Voice tool) is provided. It is very important to support cooperative work.
In order to support cooperative work in enterprise environment, voice tool should provide flexible floor control mode. Because mixed audio is not clear in existing voice tools, they have freezing floor control mode only where members talk by turns which limits the free discussing among group. In the paper, a new mixed audio algorithm, which improves voice quality, adopted by voice tool ENVoice (Enterprise Network Voice tool) is provided. It is very important to support cooperative work.
2003, 25(12): 1714-1719.
Abstract:
The Sarabandis Calibration Algorithm(SCA) using distributed targets is modified in the paper. Then the calibration experiment with the Modified Sarabandis Calibration Algorithm(MSCA) is carried out, using the uncalibrated image data and calibrated image data from the same scene obtained by SIR-C system L band SAR. Finally, the calibration result of MSCA is compared with that obtained by SIR-C calibration group and the performance of MSCA is verified.
The Sarabandis Calibration Algorithm(SCA) using distributed targets is modified in the paper. Then the calibration experiment with the Modified Sarabandis Calibration Algorithm(MSCA) is carried out, using the uncalibrated image data and calibrated image data from the same scene obtained by SIR-C system L band SAR. Finally, the calibration result of MSCA is compared with that obtained by SIR-C calibration group and the performance of MSCA is verified.
2003, 25(12): 1720-1724.
Abstract:
Due to the circuit topology of EPC used in spaceborne TWT amplifier, its harmonic has complex spectrum and great effect on reliability. In this paper, the modulation theory is applied to analyze the cause and calculate the spectrum of harmonic of EPC, also the experimental results are given. The conclusion of this paper will help both in suppressing the harmonic of EPC and improving the reliability of TWTA.
Due to the circuit topology of EPC used in spaceborne TWT amplifier, its harmonic has complex spectrum and great effect on reliability. In this paper, the modulation theory is applied to analyze the cause and calculate the spectrum of harmonic of EPC, also the experimental results are given. The conclusion of this paper will help both in suppressing the harmonic of EPC and improving the reliability of TWTA.
2003, 25(12): 1725-1728.
Abstract:
A methodology to realize continuous-time current-mode filters using low-voltage Multi-output Current-mode Differential Integrator (MCDI) is presented. At first, the char-acteristics of MCDI and the proposed filters which employ MCDI are analyzed and simu-lated. Simulation results not only predict second-order band-pass filter dissipating as little as 0.6mW power or so with 3.3V power supply using 0.5/xm CMOS technology, while the center frequency of which can be tuning in a wide range, but also with the advantages such as simple structure, good symmetry, low harmonic distortion, and suitable for integration.
A methodology to realize continuous-time current-mode filters using low-voltage Multi-output Current-mode Differential Integrator (MCDI) is presented. At first, the char-acteristics of MCDI and the proposed filters which employ MCDI are analyzed and simu-lated. Simulation results not only predict second-order band-pass filter dissipating as little as 0.6mW power or so with 3.3V power supply using 0.5/xm CMOS technology, while the center frequency of which can be tuning in a wide range, but also with the advantages such as simple structure, good symmetry, low harmonic distortion, and suitable for integration.
2003, 25(12): 1695-1702.
Abstract:
A novel Generalized MultiCarrier CDMA (GMC CDMA) transmission scheme has been proposed recently. With a block-wise transmission and spreading, GMC CDMA has been proven to be able to eliminate intersymbol interference and multiuser interference, while guaranteeing a good symbol recovery in multipath fading channel with improved bandwidth efficiency. This paper provides an intuition for the principle and design of GMC CDMA, summarizes research advancement in GMC CDMA and discusses several hot-spots of the research in the future.
A novel Generalized MultiCarrier CDMA (GMC CDMA) transmission scheme has been proposed recently. With a block-wise transmission and spreading, GMC CDMA has been proven to be able to eliminate intersymbol interference and multiuser interference, while guaranteeing a good symbol recovery in multipath fading channel with improved bandwidth efficiency. This paper provides an intuition for the principle and design of GMC CDMA, summarizes research advancement in GMC CDMA and discusses several hot-spots of the research in the future.
