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A frequency-domain algorithm FOR MULTIFRAME DETECTION AND ESTIMATION OF DIM TARGETS

IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 1990年第4期12卷 398-401页

作者： PORAT, B FRIEDLANDER, B SIGNAL PROC TECHNOL LTD PALO ALTOCA 94303

An algorithm for detecting moving targets by imaging sensors and estimating their trajectories is proposed. The algorithm is based on directional filtering in the frequency domain, using a bank of filters for all possible target directions. The directional filtering effectively integrates the target signal, resulting in an improved signal-to-noise ratio. Working in the frequency domain facilitates a considerable reduction in computational requirements compared to time-domain algorithms. The algorithm is described in detail, and its false alarm and detection probabilities are analyzed.

关键词： frequency domain analysis frequency estimation Signal processing algorithms Trajectory Signal to noise ratio Image sensors Filtering algorithms Target tracking Optical filters Filter bank INSPEC: Controlled Indexing tracking systems computerised picture processing fast Fourier transforms filtering and prediction theory INSPEC: Non-Controlled Indexing detection probabilities fast Fourier transforms computerised picture processing multiframe estimation trajectories estimation frequency domain algorithm multiframe detection dim targets moving targets imaging sensors directional filtering

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A fast frequency domain notch periodogram algorithm

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SIGNAL PROCESSING 2001年第7期81卷 1449-1463页

作者： Macleod, MD Univ Cambridge Dept Engn Signal Proc Grp Cambridge CB2 1PZ England

The notch periodogram is an algorithm which may be used iteratively for detection and super-resolution frequency estimation of multiple sinusoids ill noise (harmonic analysis). A general notch periodogram algorithm has been described for an arbitrary number of notch frequencies;there is also an approximate algorithm for well separated notch frequencies or well separated clusters of notches, which has reduced computation load. However, the computation load of these algorithms is high, especially because almost ail the computation is repeated for each iteration. This paper describes frequency domain notch periodogram algorithms which greatly reduce the computation load. After a single FFT of the data, iterated notch periodograms are computed by operations in the frequency domain. When refining notch frequencies, the notch periodogram only has to be computed over a narrow frequency range, and the new algorithms do this efficiently. Further speedups are achieved using new DFT and periodogram interpolation techniques which may be used to reduce the required zero-padding factor, and by an algorithm for fast approximation of the denominator to any specified accuracy. Representative speedup factors from 10 to over 100 are achieved. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： harmonic analysis periodogram notch periodogram frequency domain algorithm fast algorithm interpolation sinusoid estimation frequency estimation tone parameter estimation

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frequency domain set membership fast normalised LMS adaptive algorithm

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ELECTRONICS LETTERS 1999年第11期35卷 865-867页

作者： Pushparajah, SJ Chambers, JA Univ London Imperial Coll Sci Technol & Med Dept Elect & Elect Engn Commun & Signal Proc Grp London SW7 2BT England

The concept of set membership (SM) adaptive filtering is extended to the frequency domain and a novel frequency domain SM algorithm is derived. Simulations show that the new SM algorithm has a much improved convergence rate over the conventional fast normalised least mean square (FNLMS) algorithm with identical misadjustment performance. Moreover, the SM algorithm has the same order of computational complexity as the FNLMS algorithm.

关键词： filtering theory convergence rate Filtering methods in signal processing adaptive filters frequency domain algorithm Interpolation and function approximation (numerical analysis) Signal processing theory misadjustment performance fast normalised LMS adaptive algorithm convergence of numerical methods computational complexity set membership adaptive filtering least mean squares methods

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frequency domain Panoramic Imaging algorithm for Ground-Based ArcSAR

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SENSORS 2020年第24期20卷 7027页

作者： Lin, Yun Liu, Yutong Wang, Yanping Ye, Shengbo Zhang, Yuan Li, Yang Li, Wei Qu, Hongquan Hong, Wen North China Univ Technol Sch Informat Sci & Technol Beijing 100144 Peoples R China Chinese Acad Sci Aerosp Informat Res Inst Beijing 100049 Peoples R China

The ground-based arc-scanning synthetic aperture radar (ArcSAR) is capable of 360 degrees scanning of the surroundings with the antenna fixed on a rotating arm. ArcSAR has much wider field of view when compared with conventional ground-based synthetic aperture radar (GBSAR) scanning on a linear rail. It has already been used in deformation monitoring applications. This paper mainly focuses on the accurate and fast imaging algorithms for ArcSAR. The curvature track makes the image focusing challenging and, in the classical frequency domain, fast imaging algorithms that are designed for linear rail SAR cannot be readily applied. This paper proposed an efficient frequency domain imaging algorithm for ArcSAR. The proposed algorithm takes advantage of the angular shift-invariant property of the ArcSAR signal, and it deduces the accurate matched filter in the angular-frequency domain, so panoramic images in polar coordinates with wide swath can be obtained at one time without segmenting strategy. When compared with existing ArcSAR frequency domain algorithms, the proposed algorithm is more accurate and efficient, because it has neither far range nor narrow beam antenna restrictions. The proposed method is validated by both simulation and real data. The results show that our algorithm brings the quality of image close to the time domain back-projection (BP) algorithm at a processing efficiency about two orders of magnitude better, and it has better image quality than the existing frequency domain Lee's algorithm at a comparable processing speed.

关键词： ground-based synthetic aperture radar (GBSAR) arc-scanning synthetic aperture radar (ArcSAR) SAR imaging algorithm frequency domain algorithm panoramic imaging

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Blind adaptive channel mismatch equalisation method for GNSS antenna arrays

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IET RADAR SONAR AND NAVIGATION 2018年第4期12卷 383-389页

作者： Lu, Zukun Chen, Huaming Chen, Feiqiang Nie, Junwei Ou, Gang Natl Univ Def Technol Coll Elect Sci 109 Deya Rd Changsha Hunan Peoples R China

A blind adaptive channel mismatch equalisation method for global navigation satellite system (GNSS) antenna arrays is proposed. The anti-jamming performance of the antenna arrays is limited by the channel mismatch that is a relative characteristic of each radio frequency channel but not an absolute non-ideal characteristic. To pre-process the received data in the frequency domain, the least mean square (LMS) algorithm is used. The reference signal in LMS is the received data in the reference element. The purpose of pre-processing is to make the received data in the other elements approach the reference signal, which, in essence, is to equalise the mismatched channel. Without any auxiliary sensors and calibration source, this method can estimate the channel characteristics relative to the reference elements. Simulations and experimental results show that the proposed method is significant in improving the anti-jamming performance.

关键词： channel estimation blind equalisers adaptive equalisers satellite navigation satellite antennas antenna arrays jamming interference suppression least mean squares methods frequency-domain analysis blind adaptive channel mismatch equalisation method GNSS antenna array Global Navigation Satellite System antijamming performance radiofrequency channel least mean square algorithm LMS algorithm frequency domain algorithm auxiliary sensor calibration source channel estimation

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Overview of Pixel Level Image Fusion algorithm

Overview of Pixel Level Image Fusion Algorithm

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International Forum on Computer and Information Technology (IFCIT)

作者： Li, Mingjing Dong, Yubing Li, Jie Changchun Univ Coll Elect & Informat Engn Changchun 130022 Peoples R China

ISBN: (纸本)9783038350194

Pixel level image fusion algorithm is one of the basic algorithms in image fusion, which is mainly divided into time domain and frequency domain algorithm. The weighted average algorithm and PCA (principal component analysis) are popular algorithms in time domain. Pyramid algorithm and wavelet algorithm are usually used to fuse two or multiple images in frequency domain. In this paper, pixel level image fusion algorithm was summarized, including of operation, characteristics and application etc. MATLAB simulation shows that effect of frequency domain algorithm is better than time domain algorithm. Evaluation criteria mainly refer to entropy, cross entropy, the mean and standard deviation etc. Evaluation standard is the reference of fusion effects, different evaluation criteria could be selected according to different fused image and different fusion purpose.

关键词： pixel level image fusion time domain algorithm frequency domain algorithm

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Iterative Intercarrier Interference Mitigation for Mobile MIMO-OFDM Systems

Iterative Intercarrier Interference Mitigation for Mobile MI...

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22nd IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： Zhang, Yang Li, Jiandong Pang, Lihua Ding, Zhi Xidian Univ State Key Lab Integrated Serv Networks Xian 710071 Peoples R China Univ Calif Davis Dept Elect & Comp Engn Davis CA 95616 USA

ISBN: (纸本)9781457713484

Multicarrier transmission over time varying frequency selective fading channels is investigated and a model for such a transmission scheme with emphasis on Multiple Input Multiple Output Orthogonal frequency Division Multiplexing (MIMO-OFDM) systems is developed. The fast fading can destroy the orthogonality of subcarriers and cause serious InterCarrier Interference (ICI), thus leading to significant performance degradation that becomes severe as Doppler shift increases. To tackle this problem, a frequency domain iterative ICI mitigation algorithm is mathematically derived. By fully exploiting the separation property of Channel Transfer Function (CTF) matrix, ICI can be iteratively subtracted from received symbols and then Parallel Interference Cancellation (PIC) detection is performed to suppress multistream interference among different antennas. In particular, the complexity of the proposed strategy can be drastically reduced by restricting the interference computation to limited eighteen adjacent subcarriers, whereas the performance loss is quite minor. Simulation results illustrate that this scheme can effectively alleviate the impairment of ICI and asymptotically approach the ICI free performance at low-to-moderate Signal-to-Noise Ratio (SNR).

关键词： Complexity theory Doppler shift Doppler shift Equalizers Interference MIMO MIMO communication OFDM OFDM modulation Signal to noise ratio adjacent subcarriers channel transfer function matrix fading channels frequency domain algorithm frequency-domain analysis intercarrier interference interference suppression iterative intercarrier interference mitigation iterative methods mobile MIMO-OFDM systems multicarrier transmission multiple input multiple output systems multistream interference suppression orthogonal frequency division multiplexing parallel interference cancellation signal-to-noise ratio subcarrier orthogonality time varying frequency selective fading channels time-varying channels

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