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4th International Conference on Agents and Artificial Intelligence

作者： Ping, ZiLiang Jiang, YongJing Beijing Univ Post & Commun Centenary Coll Beijing Peoples R China

ISBN: (纸本)9789898425959

A fast and accurate algorithm for computation of multi-distorted invariant Complex Exponent Moments (CEMs) is presented in the paper. An image function in polar coordinate system, f(p)(r, theta), was divided into 2-D discrete image matrix in which the radial variables on lines and angle variables on columns. 2-D Fast Fourier Transform (fft) was excuted for the matrix and the Complex Exponent Moments (CEMs) can be obtained. The multi-distorted invariance and the excellent performance of Complex Exponent Moments (CEMs) were demonstrated. The Complex Exponent Moments (CEMs) were applied in human face recognition.

关键词： Multi-distorted invariance fft algorithm Compex Exponent Moments (CEMs) Human face recognition

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Effect Analysis of the Digital Spectrometer fft algorithm on THz Atmospheric Limb Sounder (TALIS) System Sensitivity

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REMOTE SENSING 2021年第15期13卷 2921-2921页

作者： Xu, Haowen Lu, Hao Wang, Zhenzhan He, Wenming Wang, Wenyu Chinese Acad Sci Natl Space Sci Ctr Key Lab Microwave Remote Sensing Beijing 100190 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

THz Atmospheric Limb Sounder (TALIS) is a microwave radiometer designed by the National Space Science Center of the Chinese Academy of Sciences (NSSC, CAS) for measuring the vertical distribution of temperature and chemical constituents in the middle and upper atmosphere. The digital spectrometer is an important part of TALIS' back end, which mainly realizes the function of spectral analysis. The radix 16 real-time complex fast Fourier transform (fft) algorithm used in the digital spectrometer was obtained by improving and combining the parallel processing and complex processing of the fft algorithm. In this study, the digital spectrometer parameter selection is systematically presented, and the effect of the digital spectrometer fft algorithm on the TALIS system sensitivity is analyzed based on the TALIS system simulation model we established in the previous stage of this research. The results show that the actual full-band sensitivity obtained after using the fft algorithm is consistent with the ideal full-band sensitivity of TALIS for different integration time, spectral resolutions, and quantization bits. However, the results of the comparison of the actual sub-band sensitivity after using the fft algorithm with the ideal sub-band sensitivity show that the deterioration of the sub-band sensitivity will be caused by the fft algorithm. The mean value of the deterioration ratio was found to be approximately 18%, and the maximum value of the deterioration ratio was approximately 33%.

关键词： TALIS digital spectrometer fft algorithm system parameter sensitivity effect analysis

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An IDL/ENVI implementation of the fft-based algorithm for automatic image registration

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COMPUTERS & GEOSCIENCES 2003年第8期29卷 1045-1055页

作者： Xie, HJ Hicks, N Keller, GR Huang, HT Kreinovich, V Univ Texas PACES Dept Geol Sci El Paso TX 79968 USA Univ Texas PACES Dept Comp Sci El Paso TX 79968 USA

Georeferencing images is a laborious process so schemes for automating this process have been under investigation for some time. Among the most promising automatic registration algorithms are those based on the fast Fourier transform (fft). The displacement between two given images can be determined by computing the ratio F-1 conj(F-2)/J\F1F2\, and then applying the inverse Fourier transform. The result is an impulse-like function, which is approximately zero everywhere except at the displacement that is necessary to optimally register the images. Converting from rectangular coordinates to log-polar coordinates, shifts representing rotation and scaling can also determined to complete the georectification process. A fft-based algorithm has been successfully implemented in Interactive Data Language (IDL) and added as two user functions to an image processing software package-ENvironment for Visualizing Images (ENVI) interface. ENVI handles all pre- and post-processing works such as input, output, display, filter, analysis, and file management. To test this implementation, several dozen tests were conducted on both simulated and "real world" images. The results of these tests show advantages and limitations of this algorithm. In particular, our tests show that the accuracy of the resulting registration is quite good compared to current manual methods. (C) 2003 Elsevier Ltd. All rights reserved.

关键词： georeferencing image fft algorithm image processing IDL/ENVI ENVI user function

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fft optimization algorithm and realization of MATLAB

FFT optimization algorithm and realization of MATLAB

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5th International Conference on Digital Image Processing (ICDIP)

作者： Cui, Chang Zhao, Qiang Liaoning Shihua Univ Sch Informat & Control Engn Fushun 113001 Peoples R China

ISBN: (纸本)9780819493057

In order to realize the fft algorithm more flexibly and effectively, this paper analyzed four kinds of amplitude spectrum or power spectrum correction methods, that is, ratio correction method, energy centrobaric correction method, phase difference method and fft + FT spectrum analysis method. On this basis, a double-window function spectrum estimation algorithm was introduced, which was a kind of conjoint analysis algorithm with rectangular window function and improved window function. The algorithm could improve the amplitude estimation accuracy in the case of not reducing the frequency resolution. The effectiveness of this algorithm was proved by using MATLAB software. The simulation results show that the double-window function spectrum estimation algorithm significantly decreases the amplitude estimation error brought by the picket fence effect, and realizes the optimization of fft algorithm.

关键词： fft algorithm optimization window function spectrum correction

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A 3-D Precorrected fft algorithm For Electrically Large Objects in Planarly Layered Media

A 3-D Precorrected FFT Algorithm For Electrically Large Obje...

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International Symposium on Antennas Propagation and EM Theory

作者： Lan-Wei Guo Yin Li Yongpin P. Chen Jun Hu Joshua Le-Wei Li Institute of Electromagnetics and School of Electronic Engineering University of Electronic Science and Technology of China

ISBN: (纸本)9781467317993

A three-dimensional (3D) pre-corrected fast Fourier transform (pfft) is presented for the fast analysis of electromagnetic (EM) scattering from electrically large perfect electrically conducting structures embedded inside a planarly layered medium. The mixed-potential integral equation (MPIE) is used to formulate the problem and the method of moments (MOM) with Rao-Wilton-Glisson (RWG) basis function is employed to solve the integral equation. In order to avoid direct numerical computation of Sommerfeld integrals (SIs), the two-level discrete complex image method (DCIM) is employed to expedite the matrix filling process. In the iterative stage, the pfft method is further adopted to accelerate the matrix-vector product, since the resulting matrix contains both cyclic convolution and correlation terms after proper splitting. Moreover, the incomplete LU preconditioner is applied to improve the convergence of the matrix equation. Numerical results are presented to show the efficiency and capability of the method.

关键词： Electricity integration fft algorithm numerical calculation LINEAR EQUATION,MATRIX Riccati matrix equation Lyapunov matrix equations Cross product binary large object Iterative Equation

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PERFORMANCE ANALYSIS OF fft algorithmS ON MULTIPROCESSOR SYSTEMS

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IEEE TRANSACTIONS ON SOFTWARE ENGINEERING 1983年第4期9卷 512-521页

作者： BHUYAN, LN AGRAWAL, DP WAYNE STATE UNIV DEPT ELECT & COMP ENGNDETROITMI 48202

A decimation-in-time radix-2 fast Fourier transform (fft) algorithm is considered for implementation in multiprocessors with shared bus, multistage interconnection network, and in mesh connected computers. Results are obtained for data allocation, interprocessor communication, approximate computation time, and speedup of an N point fft on any P available processing elements (PEs). A radix-r fft algorithm is further generalized. An N by N point 2-dimensional discrete Fourier transform implementation also is considered when one or more rows of the input data matrix are allotted to each PE. A performance comparison is conducted primarily between a shared bus multiprocessor and a computer with multistage interconnection network. The latter is shown to give much higher speedup for P greater than 16 and is more cost-effective even with the high cost of switches. N, P, and r are all powers of 2.

关键词： Two Dimensional DFT fft algorithm Interprocessor Communication Multiprocessor Systems Performance Analysis

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Adaptive algorithm Based on fft for Frequency Estimation

Adaptive Algorithm Based on FFT for Frequency Estimation

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2nd International Conference on Measurement, Information and Control (ICMIC)

作者： Lv, Jun Sun, Weitao Li, Tong Acad Armored Force Engn Dept Informat Engn Beijing Peoples R China

ISBN: (纸本)9781479913909

The performance of DFT (Discrete Fourier Transform) algorithm about frequency estimation is obviously declined, because the DFT spectrums have the problem of energy leakage and picket fence effect. Aiming at this problem, an adaptive algorithm based on fft for frequency estimation is presented. In this paper we analysis the performance of Rife algorithm and point out that the perfor mance is poor when the true frequency is much close to quantized frequency of DFT. The performance of segmented-fft (Fast Fourier Transform) phase difference method is also analyzed, and we point out that the performance is poor when the phase difference of the maximum spectral line is big. This adaptive algorithm is a combination of these two algorithms. The adaptive algorithm not only retains the advantages of the two algorithms, but also effectively makes up for the shortcomings of the two algorithms. The simulation results show that the anti-noise performance and stability of algorithm have significantly improved.

关键词： fft algorithm Rife algorithm Phase difference algorithm for frequency Frequency estimation Adaptive algorithm

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Research and Design of Data Acquisition and Processing algorithm Based on Improved fft 31

Research and Design of Data Acquisition and Processing Algor...

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31st Chinese Control And Decision Conference (CCDC)

作者： Luo, Chenhu Xu, Xianglian An, Mengqiang Mao, Lukai Zhou, Wei Wuhan Univ Technol Sch Automat Wuhan 430070 Peoples R China

ISBN: (纸本)9781728101057

From the aspects of energy saving and emission reduction, data monitoring and analysis, the monitoring requirements of distribution system and equipment are emphatically analyzed, a set of power energy efficiency monitoring terminal which can collect and process various electrical data is put forward, and the core algorithm of data acquisition and processing system of this terminal is studied and designed in this paper. The main contents of this paper include the detailed design of the fft algorithm for harmonic analysis of devices, and the fft algorithm using rectangular window, Manning window, I lamming window, single-peak spectral line interpolation, bimodal spectral line interpolation and other interpolation methods is compared and analyzed, finally, the improved fft algorithm is proposed. A large number of experiments on the system show that the improved ITT algorithm can effectively improve the calculation accuracy of harmonic analysis when asynchronous sampling, and fully meet the actual needs of the power industry, so the research and design of this paper has a high theoretical reference value and practical value.

关键词： Harmonic analysis fft algorithm windowing function interpolation

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fft-based selective harmonic current control of AC filter capacitors for audible noise analysis

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MEASUREMENT & CONTROL 2021年第3-4期54卷 408-416页

作者： Han, Jingang Sun, Shuoshuo Zheng, Shouzhi Gao, Yang Wang, Yide Tang, TianHao Shanghai Maritime Univ Inst Elect Drives & Control Syst 1550 Haigang Ave Shanghai 201306 Peoples R China Univ Nantes IETR UMR 6164 CNRSPolytech Nantes Nantes Pays De La Loir France

With the development of High Voltage Direct Current (HVDC) and ultra HVDC, a growing number of high voltage film filter capacitors have been installed for harmonic suppression. But the capacitors generate severe audible noise in the converters, which has become more and more serious. Then it is important to imitate the practical working situation of capacitors for the research of noise characteristics to improve the capacitive performance in lab. In this paper, a fft-based harmonic current control method is proposed for audible noise analysis of AC filter capacitor. Firstly, mathematical model of the Harmonic Current Injection System (HCIS) is built based on MATLAB. Then a Fast Fourier Transform (fft) harmonics detection method is analyzed and used to detect the amplitude and phase of each harmonic considering a number of harmonic currents flowing through AC filter capacitors. Since the amplitude and phase spectrum of capacitor current are obtained, the Proportional Integral (PI) regulator is applied to adjust the specified harmonic amplitude to achieve zero-error control. Then accurate harmonic current can be injected to the tested capacitor and it will help to acquire the noise characteristics of the tested plant. At last, the simulation and experimental results validate the proposed strategy.

关键词： Harmonic detection AC filter capacitors current control fft algorithm

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The pricing of compound option under variance gamma process by fft

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COMMUNICATIONS IN STATISTICS-THEORY AND METHODS 2021年第24期50卷 6122-6136页

作者： Li, Cuixiang Liu, Huili Wang, Mengna Li, Wenhan Hebei Normal Univ Coll Math & Informat Sci Shijiazhuang 050024 Hebei Peoples R China Hebei GEO Univ Coll Math & Phys Shijiazhuang Hebei Peoples R China

In this paper, we price a compound option with log asset price following an extended variance gamma process. The extended variance gamma process can control the skewness and kurtosis. The parameters of the model are estimated via the maximum likelihood method from historical data. We start with finding the risk neutral Esscher measure under which the discounted asset price process is a martingale. Then we derive an analytical pricing formula for compound option in terms of the Fourier integral of the characteristic function of extended variance gamma process, and we use this formula, in combination with the fft algorithm, to calculate the compound option price across the whole spectrum of the exercise price. Finally, we present some numerical results for illustration.

关键词： Compound option variance gamma process Fourier transform Esscher transform fft algorithm

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