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distributed programming of a hyperspectral image registration algorithm for heterogeneous GPU clusters

JOURNAL OF PARALLEL AND distributed COMPUTING 2021年 151卷 86-93页

作者： Fernandez-Fabeiro, Jorge Gonzalez-Escribano, Arturo Llanos, Diego R. Univ Valladolid Dept Informat Valladolid Spain

Hyperspectral image registration is a relevant task for real-time applications such as environmental disaster management or search and rescue scenarios. The HYFMGPU algorithm was proposed as a single-GPU high-performance solution, but the need for a distributed version has arisen due to the continuous evolution of sensors that generate images with finer spatial and spectral resolutions. In a previous work, we simplified the programming of the multi-device parts of an initial MPI+CUDA multi-GPU implementation of HYFMGPU by means of Hitmap, a library to ease the programming of parallel applications based on distributed arrays. The performance of that Hitmap version was assessed in a homogeneous GPU cluster. In this paper, we extend this implementation by means of new functionalities added to the latest version of Hitmap in order to support arbitrary load distributions for multi-node heterogeneous GPU clusters. Three different load balancing layouts are tested, which prove that selecting a proper layout affects the performance of the code and how this performance is correlated with the use of the GPUs available in the cluster. (C) 2021 Elsevier Inc. All rights reserved.

关键词： Hyperspectral imaging Image registration Heterogeneous computing distributed arrays Load balancing

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Formation Flying SAR: Analysis of Imaging Performance by Array Theory

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2021年第3期57卷 1480-1497页

作者： Renga, Alfredo Graziano, Maria Daniela Moccia, Antonio Univ Naples Federico II Naples Italy Univ Naples Federico II Space Syst & Aerosp Program Management Dept Ind Engn Naples Italy

This article analyzes the process of image synthesis for a formation flying synthetic aperture radar (FF-SAR), which is a multistatic synthetic aperture radar (SAR) based on a cluster of receiving-only satellites flying in a close formation, in the framework of the array theory. Indeed, the imaging properties of different close receivers, when analyzed as isolated items, are very similar and form the so-called common array. Moreover, the relative positions among the receivers implicitly define a physical array, referred to as spatial diversity array. FF-SAR imaging can be verified as a result of the spatial diversity array weighting the common array. Hence, different approaches to beamforming can be applied to the spatial diversity array to provide the FF-SAR with distinctive capabilities, such as coherent resolution enhancement and high-resolution wide-swath imaging. Simulation examples are discussed which confirm that array theory is a powerful tool to quickly and easily characterize FF-SAR imaging performance.

关键词： Receivers Synthetic aperture radar Imaging Satellites Transmitters Radar imaging Spatial diversity Array theory distributed arrays formation flying SAR (FF-SAR) high-resolution wide-swath imaging multistatic SAR spaceborne SAR synthetic aperture radar(sar)

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A Model for Coherent Communication Gain in distributed Wireless Networks 18

A Model for Coherent Communication Gain in Distributed Wirel...

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18th IEEE International Conference on Mobile Ad hoc and Smart Systems (IEEE MASS)

作者： Lipski, Michael, V Kompella, Sastry Narayanan, Ram M. US Naval Res Lab Washington DC 20375 USA Penn State Univ University Pk PA 16802 USA

ISBN: (纸本)9781665449359

In this paper, generalized expressions for system gain in a coherent communication system are developed. In an ad hoc or distributed network, the transmit and receive operations can be coordinated at the RF level to produce an array gain, similar to a fixed antenna array;such formations are known as coherent distributed arrays. The system examined in this paper consists of two open-loop coherent distributed arrays: one transmitter array and one receiver array. The gain of the entire system containing both arrays is described by the coherent communication gain. The concept of group array factor, which is the multi-receiver extension of array factor, is also introduced. Group array factor allows for a characterization of gain independent from propagation model and properties of the individual transmitters and receivers. The univariate optimization problem of maximizing group array factor as a function of transmitter array beam angle in the azimuth plane is described, and a practical bounding on the search space is introduced. The physical dimensions of the communication system are analyzed in terms of their influence on the objective function, and a condition for guaranteeing convexity of the bounded objective function is given. An example transmitter array-receiver array system is introduced and used to showcase the concepts herein.

关键词： Coherent communications distributed arrays beamforming ad hoc networks cognitive radio

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Experimental Demonstration and Calibration of a 16-Element Active Incoherent Millimeter-Wave Imaging Array

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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 2020年第9期68卷 3804-3813页

作者： Vakalis, Stavros Gong, Liang He, Yuxiao Papapolymerou, John Nanzer, Jeffrey A. Michigan State Univ Dept Elect & Comp Engn E Lansing MI 48824 USA Amazon Bellevue WA 98004 USA

In this article, an active incoherent millimeter-wave imaging array is presented, along with its calibration procedure. Active incoherent millimeter-wave imaging uses the transmission of incoherent signals from multiple transmitters to mimic the properties of thermal radiation, enabling interferometric image reconstruction that can be realized in a snap-shot mode, without beamsteering. Due to the use of transmitters, the sensitivity requirement on the receivers is significantly relaxed compared with passive millimeter-wave imaging systems that detect low-power thermal radiation, making it possible to use standard commercial hardware, therefore decreasing the cost considerably. No exact knowledge of the transmit illumination is needed;thus, the coordination of the transmitters is minimal, further simplifying the system implementation. In this work, a 16-element K-a-band millimeter-wave imager is built and presented using commercial components and in-house fabricated antennas, along with a calibration procedure to account for amplitude and phase variations in the hardware. Experimental 2-D snapshot image reconstructions are presented.

关键词： Calibration distributed arrays incoherent imaging interferometric imaging millimeter-wave imaging noise radar redundancy

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distributed transmit array multi-tone carrier synchronization

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PHYSICAL COMMUNICATION 2021年 47卷 101405-101405页

作者： Ding, Yuan Fusco, Vincent Li, Xingwang Heriot Watt Univ Inst Sensors Signals & Syst ISSS Edinburgh EH14 4AS Midlothian Scotland Queens Univ Belfast Inst Elect Commun & Informat Technol ECIT Belfast BT3 9DT Antrim North Ireland Henan Polytech Univ Sch Phys & Elect Informat Engn Jiaozuo 454000 Henan Peoples R China

An open-loop (OL) method to enable distributed transmit beamforming is presented in this paper. The approach eliminates the need for feedback to distant receive nodes by using multiple tones to set a coherent phase across the distributed array. This arrangement is able to constantly keep the array synchronized to avoid the frequency drifting of the local oscillators (LOs) equipped by distributed communication nodes, even while transmit beamforming is taking place. This is made possible because the synchronization is achieved through radio frequency (RF) carriers at frequencies other than the beamforming frequency. This enables uninterrupted beamforming, which is not possible in previous carrier synchronization algorithms due to half-duplex limitation. The noise performance of the proposed scheme is also presented. (C) 2021 Elsevier B.V. All rights reserved.

关键词： Carrier synchronization distributed arrays distributed transmit beamforming Open-loop

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A Digital Interferometric Array with Active Noise Illumination for Millimeter-Wave Imaging at 13.7 fps

A Digital Interferometric Array with Active Noise Illuminati...

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IEEE/MTT-S International Microwave Symposium (IMS)

作者： Vakalis, Stavros Nanzer, Jeffrey A. Michigan State Univ Elect & Comp Engn E Lansing MI 48824 USA

ISBN: (纸本)9781728168159

We present millimeter-wave imagery at 13.7 frames-per-second (fps) using a digital 16-element interferometric antenna array operating at 37 GHz. The scene is illuminated incoherently using three low-cost noise transmitters, mimicking the properties of thermal radiation. The array is based on commercial components and 3D-printed horn antennas. The system architecture is presented, along with the signal processing algorithm, and real-time imaging results.

关键词： Millimeter-wave imaging computational imaging digital antenna arrays distributed arrays noise radar

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ESPRIT-based Calibration of Multiple Sonobuoys Using a Moving Source

ESPRIT-based Calibration of Multiple Sonobuoys Using a Movin...

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Global OCEANS Singapore - U.S. Gulf Coast Conference

作者： Ganti, Anil Krolik, Jeffrey Duke Univ Elect & Comp Engn Durham NC 27708 USA

ISBN: (纸本)9781728154466

distributed sonar arrays that are coherently processed offer high gain over diffuse noise and target resolution but with minimal hardware. The low-cost and ad-hoc nature of these arrays make them flexible and easy to scale but it also brings additional calibration challenges. The positions of individual sub-arrays may only be known up to the accuracy of an on-board GPS device, which will in general be inadequate for beamforming. In this paper we present a distributed array position calibration method using a single, tonal moving source of opportunity. The distributed array is re-partitioned into uncalibrated sparse arrays, whose steering matrices are estimated using the ESPRIT algorithm. The source and sub-array positions are then jointly estimated with the aid of noisy AIS data. We show this method to be effective for a minimum of a single moving source consisting of just two tones.

关键词： passive sonar distributed arrays ad-hoc arrays sparse arrays multi-aperture arrays array calibration ESPRIT

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Analysis of Element Failures in Active Incoherent Microwave Imaging arrays Using Noise Signals

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IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS 2019年第2期29卷 161-163页

作者： Vakalis, Stavros Nanzer, Jeffrey A. Michigan State Univ Dept Elect & Comp Engn E Lansing MI 48824 USA

An analysis of the effects of receiver element failures in active incoherent microwave imaging arrays is presented. Active incoherent microwave imaging is a new imaging method that uses transmission of noise signals combined with a sparse array using interferometric processing. In this method, the failure of individual receiver array elements results in gradual degradation of the image, rather than losses of pixels. This letter analyzes the image degradation in terms of the root-mean-square error (RMSE) of the image formed with randomly failed elements compared to the image formed with all elements. Measured data using a 5.85-GHz experimental imaging system show that RMSE below 10% can be maintained with failure rates extending up to 25%. Modeled image formation performance and the sidelobe level of the point spread function is shown to track well with the measured data for up to 50% element failures, indicating a robust method for predicting imaging performance.

关键词： distributed arrays distributed radar failure analysis interferometric imaging radar imaging

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AN ONLINE EM ALGORITHM FOR SOURCE EXTRACTION USING distributed MICROPHONE arrays

AN ONLINE EM ALGORITHM FOR SOURCE EXTRACTION USING DISTRIBUT...

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21st European Signal Processing Conference (EUSIPCO)

作者： Taseska, Maja Habets, Emanuel A. P. Int Audio Labs Erlangen D-91058 Erlangen Germany

ISBN: (纸本)9781479936878

Expectation maximization (EM)-based clustering is applied in many recent multichannel source extraction techniques. The estimated model parameters are used to compute time-frequency masks, or estimate second order statistics (SOS) of the source signals. However, in applications with moving sources where the model parameters are time-varying, the batch EM algorithm is inapplicable. We propose an online EM-based clustering of position estimates, where the model parameters are estimated adaptively. A direct-to-diffuse ratio-based speech presence probability is used to detect noisy observations and reduce diffuse and spatially incoherent noise. The desired source signal is extracted by a multichannel Wiener filter computed using SOS estimated from the time-varying model parameters. We show that the signal of a moving source can be extracted, while reducing moving interferers and background noise.

关键词： expectation maximization online learning PSD matrix estimation distributed arrays

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SPOTFORMING USING distributed MICROPHONE arrays

SPOTFORMING USING DISTRIBUTED MICROPHONE ARRAYS

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14th IEEE Workshop on Applications of Signal Processing to AudNew Paltzio and Acoustics (WASPAA)

作者： Taseska, Maja Habets, Emanuel A. P. Int Audio Labs Erlangen D-91058 Erlangen Germany

ISBN: (纸本)9781479909728

Extracting sounds that originate from a specific location, while reducing noise and interferers is required in many hands-free communications systems. We propose a spotforming approach that uses distributed microphone arrays and aims at extracting sounds that originate from a pre-defined spot of interest (SOI), while reducing background noise and sounds that originate from outside the SOI. The spotformer is realized as a linear spatial filter, which is based on the signal statistics of sounds from the SOI, the signal statistics of sounds outside the SOI and the background noise signal statistics. The required signal statistics are estimated from the microphone signals, while taking into account the uncertainty in the location estimates of the desired and the interfering sound sources. The applicability of the method is demonstrated by simulations and the quality of the extracted signal is evaluated in different scenarios.

关键词： distributed arrays PSD matrix estimation source extraction spatial filtering

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