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A Fast Multi-Source Sound DOA Estimator Considering Colored Noise in circular array

IEEE SENSORS JOURNAL 2019年第16期19卷 6914-6926页

作者： Yao, Yuhong Guo, Terry N. Chen, Zhe Fu, Chong Northeastern Univ Sch Comp Sci & Engn Shenyang 110819 Liaoning Peoples R China Tennessee Technol Univ Ctr Mfg Res Cookeville TN 38505 USA

Sound direction of arrival (DOA) estimation keeps finding new applications. For instance, real-time sound DOA estimation enabled by acoustic sensors on low-cost and limited-resource devices can enhance or create many consumer use cases. Indeed, tracking multiple moving sound sources in noisy or reverberated condition with a cost-effective platform is highly desirable. In this paper, we develop a computation-aware DOA estimator that uses weighting in frequency domain. It relies on single source zones (SSZs) and circular integrated cross spectrum (CICS) techniques and peak search on DOA histogram. The existing histogram-based multi-source DOA estimation is fundamentally limited in angular resolution, and the CICS process is very time consuming. To tackle these problems, we propose a weighting method that exploits the unevenness of intermediate DOA estimation errors over the frequencies of interest, and a simple yet effective strategy to reduce search range. Two underlying mechanisms, the impact of the colored noise of microphones and the frequency-dependent behavior (statistic model) of DOA estimation errors, are unveiled. We have developed an experimental platform using commercially off-the-shelf devices to verify design objectives, including feasibility and real-time requirement. The proposed techniques are validated on the developed platform and the system performance is evaluated experimentally in a real-world environment. It is observed the DOA estimation resolution is improved roughly from 30 degrees to 15 degrees and the overall computation is reduced by 68%.

关键词： Sound DOA estimation colored noise circular array computational cost real-time processing

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The SPAC Method for a Finite M-Station circular array Using Horizontally Polarized Ambient Noise

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BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA 2011年第2期101卷 544-557页

作者： Shabani, Elham Eskandari-Ghadi, Morteza Mirzaei, Noorbakhsh Univ Tehran Inst Geophys Tehran *** Iran Univ Tehran Fac Engn Dept Engn Sci Tehran *** Iran

The spatial autocorrelation (SPAC) method is a useful tool for interpreting ambient noise, and several theoretical tools based on this method are available for data collection, processing, and analysis. The method uses the three components of seismic microtremors recorded simultaneously with arrays of different configurations and yields dispersion curves of Rayleigh and Love waves. Existing theories of the SPAC method are based on an idealized circular array with an infinite number of stations (the continuous model). Errors due to the use of a finite number of stations have been derived theoretically for vertically polarized ambient noise. This paper presents an extension of that error theory to horizontally polarized ambient noise so that it is valid for a circular array with M uniformly spaced stations. The quantities that are obtained as the output of the SPAC method, however, depend on the ratio of the power spectral densities (PSDs) of Rayleigh and Love waves, which are difficult to identify beforehand. Instead we introduce a quantity, kappa, that does not depend on the PSD ratio and therefore is more convenient for separating the properties of Rayleigh and Love waves. We derive an expression of kappa for a finite, M-station circular array (kappa(M)) and compare it with what it should be in the continuous model (kappa(T)). We illustrate kappa(M) and kappa(T) using field data from a site in Tehran and discuss their discrepancies. Finally, we demonstrate how we have estimated Love-wave phase velocities using the calculated kappa(M).

关键词： Love waves Ambient Noise error theory Rayleigh STATIONS circular array Love

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Joint direction of arrival and delay channel characteristics estimation using circular array antenna for optimal frequency-space diversity in MC/CDMA receivers

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EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS 2002年第5期13卷 495-505页

作者： Fujii, M Suzuki, S Itami, M Itoh, K Sci Univ Tokyo Dept Appl Elect Chiba 2788510 Japan

This paper derives the Maximum Likelihood (ML) algorithm for jointly estimating Direction Of Arrival (DOA) and delay path characteristics of multipath propagation by using array antennas whose elements are placed on a circular circumference. The algorithm is especially made of in a quasi-synchronous Multi-Carrier (MC) / Code Division Multiple Access (CDMA) systems in order to achieve the optimal diversity effect. The estimated channel characteristics may be used in Multiple Access Interference (MAI) cancellation or suppression, which remains as the subject of future study. Assuming in the acquisition period, e. g. the preamble period of packet transmission, mutually orthogonal codes are assigned to the set of multiple carrier channels of the CDMA users and the assignments are cyclically shifted from one symbol period to another. Each of the received carrier channel signals at each of the antenna elements is correlated on the time axis with the orthogonal code assigned to each user and in this way the data characterizing the radio wave propagation from each of the users can be separately supplied to the algorithm to follow. The algorithm performs a 2-dimensional Discrete Fourier Transform (DFT) on the signal sequence thus supplied from the antenna elements and the carrier channels, giving a sufficient statistic by which the DOA and delay path characteristics can be estimated for each of the multiple paths from each of the users. Use of the estimation is demonstrated to obtain the optimal weights for frequency-space diversity and significant improvement in Bit Error Rate (BER) performance was observed over the conventional way of obtaining the weights.

关键词： orthogonal codes Angle of arrival United States Department of Agriculture Consumers diversity effect radiowave propagation Code division multiple access diversity reception antenna element algorithms Multipath propagation circular array Antenna arrays Direction of arrival estimation

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A Novel circular array Structure and Particle Swarm Optimization in Aperture Synthesis Radiometers

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IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 2015年 14卷 1758-1761页

作者： Jang, Chol-Hyon Hu, Fei He, Feng Wu, Liang Huazhong Univ Sci & Technol Sch Elect Informat & Commun Wuhan 430074 Peoples R China Huazhong Univ Sci & Technol Natl Key Lab Sci & Technol Multispectral Informat Wuhan 430074 Peoples R China

A novel array configuration, circular lattice array (CLA), to generate uniform rectangular grid u-v coverage for aperture synthesis radiometers is introduced. Particle swarm optimization (PSO) algorithm is applied to finding optimal CLA configurations. To evaluate the advantages of the CLA over previously proposed circular arrays, a comparative study is carried out by analyzing the performance of the CLA in terms of both the number of samples in u-v coverage and the computation cost of the fitness function in optimization algorithm. The obtained optimization results for 5-30 elements are also presented.

关键词： Aperture synthesis radiometers circular array particle swarm optimization u-v coverage

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Ultrafast Endoscopic Ultrasonography With circular array

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IEEE TRANSACTIONS ON MEDICAL IMAGING 2020年第6期39卷 2110-2120页

作者： Tan, Qingyuan Wang, Congzhi Liu, Jiamei Huang, Jiqing Li, Yongchuan Xiao, Yang Xia, Gui-Song Ma, Teng Zheng, Hairong Chinese Acad Sci Inst Biomed & Hlth Engn Shenzhen Inst Adv Technol Shenzhen 518055 Peoples R China Wuhan Univ Sch Comp Sci State Key Lab LIESMASRS Wuhan 430072 Peoples R China

Rapid development of ultrafast ultrasound imaging has led to novel medical ultrasound applications, including shear wave elastography and super-resolution vascular imaging. However, these have yet to incorporate endoscopic ultrasonography (EUS) with a circular array, which provides a wider view in the alimentary canal than traditional linear and convex arrays. A coherent diverging wave compounding (CDWC) imaging method was proposed for ultrafast EUS imaging and implemented on a custom circular array. In CDWC, virtual acoustic point sources are allocated and virtually insonified diverging waves from each source are achieved by adjusting all circular array elements' emission time delays. Diverging waves emitted from different virtual sources are coherently compounded, generating synthetic transmit focusing at every location in the image plane. As the field of view of the circular array is centrally symmetric, all virtual sources are equidistantly distributed on a concentric circle of radius r. To achieve the highest frame rate possible with image quality comparable to that obtained with the traditional multi-focus imaging method, the effects of various radii r and virtual source quantities on the compounded image quality were theoretically analyzed and experimentally verified. Simulation, phantom, and ex-vivo experiments were conducted with an 8 MHz, 124-element circular array, with a 5.35 mm radius. When 16 virtual sources were used with r = 1.605 mm, image quality comparable to that obtained with the multi-focus approach was achieved at a frame rate of 1000 frames/s. This demonstrates the feasibility of the proposed ultrafast EUS imaging method and promotes further development of multi-functional EUS devices.

关键词： circular array endoscopic ultrasonography ultrafast ultrasound imaging

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2-D direction-of-arrival estimation using a linear interpolation technique for circular array

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IEICE TRANSACTIONS ON COMMUNICATIONS 2001年第9期E84B卷 2688-2696页

作者： Akiyama, T Yamaoka, T Hamada, N Keio Univ Fac Sci & Technol Yokohama Kanagawa 2238522 Japan

The MUSIC (Multiple Signal Classification) technique with the circular array can estimate both elevational and azimuthal direction-of-arrival (DOA). This conventional method can not distinguish coherent signals, therefore, it can not estimate proper DOA in the presence of coherent signals. On the other hand, limited as to uniformly spaced linear arrays, the spatial smoothing technique is shown to be effective approach in decorrelating coherent signals. This scheme can not be applied directly to the nonlinear arrays. To overcome the coherent signal nonseparation problem in the nonlinear arrays, the approach using a linear interpolation technique has been proposed. However, this approach provides DOA estimates in one dimensional. In our proposed method, we use not only a linear interpolation technique for the circular array but also the symmetry of the circular array. The computer simulation is performed to demonstrate the usefulness of our method. As its result shows, the method can perform well even in the presence of coherent signals.

关键词： 2-D DOA estimation MUSIC circular array coherent virtual array

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1.5-Dimensional circular array Transducer for In Vivo Endoscopic Ultrasonography

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IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING 2021年第10期68卷 2930-2939页

作者： Zhang, Qi Tan, Qingyuan Liu, Jiamei Chen, Weicen Huang, Jiqing Lei, Shuang Li, Yongchuan Long, Xiaojing Wang, Congzhi Xiao, Yang Wu, Dawei Zheng, Hairong Ma, Teng Chinese Acad Sci Shenzhen Inst Adv Technol Inst Biomed & Hlth EngnKey Lab Magnet Resonance Shenzhen Key Lab Ultrasound Imaging & TherapyPau Shenzhen 518055 Peoples R China Nanjing Univ Aeronaut & Astronaut State Key Lab Mech & Control Mech Struct Nanjing Peoples R China Natl Innovat Ctr Adv Med Devices Shenzhen Peoples R China

Objective: Traditional endoscopic ultrasonography (EUS), which uses one-dimensional (1-D) curvilinear or radial/circular transducers, cannot achieve dynamic elevational focusing, and the slice thickness is not sufficient. The purpose of this study was to design and fabricate a 1.5-dimensional (1.5-D) circular array transducer to achieve dynamic elevational focusing in EUS in vivo. Methods: An 84 x 5 element 1.5-D circular array transducer was successfully developed and characterized in this study. It was fabricated with PZT-5H 1-3 composite that attained a high-electromechanical coupling factor and low-acoustic impedance. The acoustic field distribution was measured with different transmission modes to validate the 1.5-D elevational beam focusing capability. The imaging performance of the 84 x 5 element 1.5-D circular array transducer was evaluated by two wire phantoms, an agar-based cyst phantom, an ex vivo swine pancreas, and an in vivo rhesus macaque rectum based on multifocal ray-line imaging method with five-row elevational beam steering. Results: It was demonstrated that the transducer exhibited a central frequency of 6.47 MHz with an average bandwidth of 50%, a two-way insertion loss of 23 dB, and crosstalk of <-26 dB around the center frequency. Conclusion: Dynamic elevational focusing and the enhancement of the slice thickness in EUS were obtained with a 1.5-D circular array transducer. Significance: This study promotes the development of multirow and two-dimensional array EUS probes for a more precise clinical diagnosis and treatment.

关键词： 1.5-D circular array digestive tract endoscopic ultrasound in vivo

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Improved Sidelobe Recognition Method Using Boresight Error in a Uniform circular array for Wideband Direction Finding System

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IEEE ACCESS 2021年 9卷 108062-108068页

作者： Kong, Deok Kyu Woo, Daewoong Kim, Jaesik Yoon, Young Joong Agcy Def Dev Daejeon South Korea Yonsei Univ Dept Elect & Elect Engn Seoul 03722 South Korea

A strong signal through the antenna sidelobes can be interpreted as a main lobe signal and may cause a major angle error in the direction finding system. An auxiliary antenna channel in the Maisel's sidelobe blanking system increases the cost, and the method using each boresight error (BSE) of the monopulse and interferometer causes many errors in the real antenna. In this paper, a sidelobe recognition method applicable to a wideband uniform circular array without auxiliary antenna channel is proposed. Four boresight errors are obtained from monopulse and interferometer in the circular array and then the maximum value of differences between boresight errors is taken and is compared to the optimal threshold value. The results have the effect of reducing errors occurring in the sidelobe region while maintaining the performance in the main lobe region. To validate the proposed method, a circular array antenna with eight wideband microstrip antennas is designed and manufactured. As a result, there is a significant improvement in the error rate compared to the existing method. It is confirmed that there is no error when the threshold value is from 0.5 degrees to 0.7 degrees at 6, 9, and 12 GHz, and the error rate is less than about 1 % when the threshold value is between 0.4 degrees and 1.0 degrees.

关键词： Antenna arrays Antennas Broadband antennas Wideband Radar antennas Pattern recognition Sensors array antenna circular array sidelobe recognition sum-delta monopulse interferometer

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Interference Reduction Characteristics by circular array Based Massive MIMO in a Real Microcell Environment

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IEICE TRANSACTIONS ON COMMUNICATIONS 2015年第8期E98B卷 1447-1455页

作者： Kataoka, Ryochi Nishimori, Kentaro Tran, Ngochao Imai, Tetsuro Makino, Hideo Niigata Univ Fac Engn Niigata 9502102 Japan NTT DOCOMO INC Res Labs Yokosuka Kanagawa 2398536 Japan

The concept of massive multiple input multiple output (MIMO) has recently been proposed. It has been reported that using linear or planar arrays to implement massive MIMO yields narrow beams that can mitigate the interference signal even if interference cancellation techniques such as zero forcing (ZF) are not employed. In this work, we investigate the interference reduction performance achieved by circular array implemented massive MIMO in a real micro cell environment. The channel state information (CSI) is obtained by using a wideband channel sounder with cylindrical 96-element array in the 2-GHz band in an urban area. circular arrays have much larger beamwidth and sidelobe level than linear arrays. In this paper, when considering the cylindrical array, the interference reduction performance between ZF and maximum ratio combining is compared when one desired user exists in the micro cell while the interference user moves around the adjacent cell. We show that ZF is essential for reducing the interference from the adjacent cell in the circular array based massive MIMO. The required number of antennas in the vertical and horizontal planes for the interference reduction is evaluated, in order to simplify the burden of signal processing for the ZF algorithm in massive MIMO. Because there are elements with low signal to noise power ratio (SNR) when considering cylindrical 96-element array, it is shown that the degradation of the signal to noise plus interference power ratio (SINR) when the number of antennas is reduced is smaller than that by ideal antenna gain reduction with a linear array. Moreover, we show that the appropriate antennas should be selected when a limited number of antennas is assumed, because the dominant waves arrive from certain specific directions.

关键词： massive MIMO circular array microcell maximum ratio combining zero forcing channel sounder

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Direction finding with a uniform circular array via single snapshot processing

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SIGNAL PROCESSING 1997年第1期56卷 17-31页

作者： Koc, AT Tanik, Y Electrical and Electronics Engineering Department Middle East Technical University Inönü Bulvari 06531 Ankara Turkey

In this work a new algorithm for multiple emitter direction finding by using a uniform circular array is proposed. The algorithm is based on single snapshot processing, and therefore, it has no restriction on the coherency of the sources. The problem formulation is based on the transformation of the snapshot. The transformed sequence is formed by taking the discrete Fourier transform of the snapshot and weighting it suitably. It contains the so-called distortion terms, which are taken into account by using an iterative correction scheme to improve the estimation accuracy. The convergence is achieved in a few steps, and a significant performance improvement is observed when the distortion terms are taken into account. The proposed bearing estimation algorithm is based on the linear prediction method developed in this study, in which the prediction filter coefficients are found by replacing the weighted data matrix by a specified rank approximation, which is obtained by its singular-value decomposition. The direction of arrival estimates are obtained from the angular locations of the prediction-error filter zeros. It is observed through computer simulations that the algorithm performance is improved as compared to that of the forward-backward linear prediction (FBLP) and the modified FBLP methods by choosing an appropriate rank for the approximating matrix. The root-mean-square errors are close to the Cramer-Rao bounds in most cases, where the aforementioned methods fail to work. (C) 1997 Elsevier Science B.V.

关键词： direction finding circular array single snapshot linear prediction

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