Science method

# Array Processing - Science method

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Publications related to Array Processing (3,604)
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High-performance sonar systems mostly combine a large sensor array and an efficient beamformer for enhancing the overall detection capabilities and estimation of Direction of Arrival (DoA) of the acoustic signal released from underwater targets in the ocean. The array geometry and the number of elements have direct influences on the beam width and...
Article
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Object detection is a technique of computer vision whose primary intent is to detect objects. The objects can be detected from any image or video feeds. Now a day’s object detection is extensively applied in video surveillance systems, human tracking, and self-driving cars. This paper presented a novel object detection approach that uses only wiref...
Article
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Distributed acoustic sensors (DAS) can monitor mechanical vibrations along thousands independent locations using an optical fibre. The measured acoustic waveform highly varies along the sensing fibre due to the intrinsic uneven DAS longitudinal response and distortions originated during mechanical wave propagation. Here, we propose a fully blind me...
Article
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This research paper aims to improve the quality of 3D printed parts made of the wax filament by implementing the Taguchi orthogonal array process optimization method. The manufactured parts can be used as cost-effective investment casting patterns. With the Taguchi method, it was concluded that the nozzle temperature has the most effect on the dime...
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In this article, the performance analysis of subspace‐based spatial‐temporal spectral estimation is investigated. Subspace methods adopt an eigenstructure approach to estimate the array observation power in the frequency‐direction (f−θ$$f-\theta$$) plane. This approach is used in many wideband array processing techniques using spatial‐temporal co...
Preprint
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Synchronization of transceiver chains is a major challenge in the practical realization of massive MIMO and especially distributed massive MIMO. While frequency synchronization is comparatively easy to achieve, estimating the carrier phase and sampling time offsets of individual transceivers is challenging. However, under the assumption of phase an...
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The endless spoofing interference affects the credibility of the navigation system seriously. In order to suppress the forward spoofing which is more threatening to military signals in GNSS, this paper proposes a spoofing suppression algorithm based on angle of arrival estimation and multi-satellite fusion. On the basis of successfully suppressing...
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In computer vision and medical image processing, object recognition is the primary concern today. Humans require only a few milliseconds for object recognition and visual stimulation. This led to the development of a computer-specific pattern recognition method in this study for identifying objects in medical images such as brain tumors. Initially,...
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The domain of spatial audio comprises methods for capturing, processing, and reproducing audio content that contains spatial information. Data-based methods are those that operate directly on the spatial information carried by audio signals. This is in contrast to model-based methods, which impose spatial information from, for example, metadata lik...
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Infrasound sensors are deployed in a variety of spatial configurations and scales for geophysical monitoring, including networks of single sensors and networks of multi-sensor infrasound arrays. Infrasound signal detection strategies exploiting these data commonly make use of inter-sensor correlation and coherence (array processing, multi-channel c...
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A wide‐angle scanning phased array based on pattern reconfigurable elements is proposed. There are seven metallic cylinders arranged on both sides of each unit separately to improve the isolation. The design of metallic cavities instead of a ground plate and cooperating with cylinders ingeniously solved the inconvenience of DC bias supply, signific...
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Microtremor array measurements, and passive surface wave methods in general, have been increasingly used to non-invasively estimate shear-wave velocity structures for various purposes. The methods estimate dispersion curves and invert them for retrieving S-wave velocity profiles. This paper summarizes principles, limitations, data collection, and p...
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Plain Language Summary Seismic noise is the vibration of Earth generated by activities other than earthquakes, such as wind and ocean waves. Signals extracted from seismic noise can be used to study Earth's interior structure in ways similar to how earthquake records have been analyzed. Most previous studies using seismic noise to study Earth struc...
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Matched field processing (MFP) techniques employing physics-based models of acoustic propagation have been successfully and widely applied to underwater target detection and localization, while machine learning (ML) techniques have enabled detection and extraction of patterns in data. Fusing MFP and ML enables the estimation of Green’s Function sol...
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Snow avalanches pose a hazard in alpine environments. There is a need to improve monitoring capabilities in order to reliably detect and locate avalanche activity, which will help to validate avalanche hazard assessments. Recent work has demonstrated the utility of infrasound as it can provide continuous monitoring and broad geographic coverage. He...
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Global Positioning System (GPS) satellites offer promising opportunity for Passive Radar systems due to their global coverage and the availability of multiple satellites throughout the world. However, their low power at ground level limits system coverage. In this paper, a GPS based Passive Radar which exploits a single illumination source, and use...
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The Kalman filter (KF) is known to loose its optimality properties when the model used does not perfectly match the true system. Extending the use of linear constraints to this filter recently proved to be efficient to mitigate a large class of parametric model mismatch, through the linearly constrained Kalman filter and minimum variance filter (LC...
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[Appearing in JGR Soild Earth under Open access] Distributed Acoustic Sensing (DAS) involves the transmission of laser pulses along a fiber-optic cable. These pulses are backscattered at fiber inhomogeneities and again detected by the same interrogator unit that emits the pulses. Elastic deformation along the fiber causes phase shifts in the backsc...
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It was recently established that when an LC transmission line with a Schottky varactor is connected to a voltage terminal, a pulse is formed whose amplitude grows exponentially leading eventually to its instability after some finite propagation time. In the present study an R2LC nonlinear transmission line, consisting of a lumped circuit with unit...
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The phase-velocity dispersion curve (DC) is an important characteristic of the propagation of surface waves in sedimentary environments. Although the procedure for DC estimation in onshore environments using ambient vibration recordings is well established, the DC estimation in offshore environments using Ocean Bottom Seismometers (OBS) array recor...
Article
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Personalized Head-Related Transfer Functions (HRTFs) are needed as part of the binaural sound individualization process in order to provide a high-quality immersive experience for a specific user. Signal processing methods for performing HRTF measurements in non-anechoic conditions are of high interest to avoid the complex and inconvenient access t...
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High-throughput genotyping of large numbers of lines remains a key challenge in plant genetics, requiring geneticists and breeders to find a balance between data quality and the number of genotyped lines under a variety of different existing genotyping technologies when resources are limited. In this work, we are proposing a new imputation pipeline...
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The problem of blind and online speaker localization and separation using multiple microphones is addressed based on the recursive expectation-maximization (REM) procedure. A two-stage REM-based algorithm is proposed: (1) multi-speaker direction of arrival (DOA) estimation and (2) multi-speaker relative transfer function (RTF) estimation. The DOA e...
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Microphone and speaker array designs have increasingly diverged from simple topologies due to diversity of physical host geometries and use cases. Effective beamformer design must now account for variation in the array’s acoustic radiation pattern, spatial distribution of target and noise sources, and intended beampattern directivity. Relevant task...
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This article deals with the application of differential geometry to the array manifolds of non-uniform linear antenna array (NULA) when estimating the direction of arrival (DOA) of multiple sources present in an environment using far field approximation. In order to resolve this issue, we utilized a doublet linear antenna array (DLA) comprising two...
Preprint
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Due to global warming, the decline in the Arctic sea ice has been accelerating over the last four decades, with a rate that was not anticipated by climate models. To improve these models, there is the need to rely on comprehensive field data. Seismic methods are known for their potential to estimate sea-ice thickness and mechanical properties with...
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We investigated models of the internal structure of initially homogeneous Moon differentiated as a result of partial melting, using data on seismic velocities according to the seismic models assume the zonal structure of the lunar mantle is a model of the Moon which was obtained with using the array processing methods of high velocities in the lowe...
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Abstract Flexible sensor arrays, such as towed and bottom‐mounted arrays, typically suffer from large shape deformations, which seriously affect the results of array processing. In this article, an innovative array shape calibration method with phase unwrapping techniques for highly deformed arrays is proposed. The deformed array is divided into se...
Article
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This paper is concerned with the problem of simultaneously tracking the direction-of-arrival (DOA) of far-field multiple moving sources/users in wireless communications using the vector-signal received by an antenna array of N elements. The antenna array can be rigid (fixed array locations) or flexible (time-varying array locations), and it is used...
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Designing beampatterns with constant beamwidth over a wide range of frequencies is useful in many applications in speech, radar, sonar and communication. In this paper, we design constant-beamwidth beamformers for concentric ring arrays. The proposed beamformers utilize the circular geometry to provide improved beamwidth consistency compared to bea...
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It is well known that the Kalman filter (KF) performance is clearly degraded in real-life applications where the system model is misspecified to a certain extent, that is, when the assumed knowledge does not perfectly match the true system dynamics. A possible way to mitigate the impact of a system model mismatch is to resort to linear constraints....
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Scope: Two experiments were performed to test the effects of rich tomato extract (Golden Tomato Extract, GTE) on human skin. In one experiment, the effects of this extract on gene expression in cultured human dermal fibroblasts were examined. In a second experiment, human subjects consumed the extract and trans-epidermal water loss (TEWL), and asp...
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This paper presents a method for the joint detection and direction of arrival (DOA) estimation of low probability of detection (LPD) signals. The proposed approach is based on using the antenna array to receive spread-spectrum signals hidden below the noise floor. Array processing exploits the spatial correlation between phase-delayed copies of the...
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Direction of Arrival (DoA) estimation using Sparse Linear Arrays (SLAs) has recently gained considerable attention in array processing thanks to their capability to provide enhanced degrees of freedom in resolving uncorrelated source signals. Additionally, deployment of one-bit Analog-to-Digital Converters (ADCs) has emerged as an important topic i...
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The detection and location capability of the International Monitoring System for small seismic events in the continental and oceanic regions surrounding the Sea of Japan is determined mainly by three primary seismic arrays: USRK, KSRS, and MJAR. Body wave arrivals are coherent on USRK and KSRS up to frequencies of around 4 Hz and classical array pr...
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This study aims to improve the multi‐array local back‐projection (MLBP) approach and to apply it to the 2019 Mw 6.4 and Mw 7.1 Ridgecrest, California earthquakes to resolve more details about their kinematic process, with the dense seismic network in California. Compared with teleseismic BPs, seismic array processing with stations located at local...
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A joint processing of direction of arrival (DOA) and signal separation for planar array is proposed in this paper. Through sensor array processing theory, the output data of a planar array can be reconstructed as a parallel factor (PARAFAC) model, which can be decomposed with the trilinear alternating least square (TALS) algorithm. Aiming at the pr...
Chapter
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Linear sparse antenna arrays have been widely studied in array processing literature. They belong to the general class of non-uniform linear arrays (NULAs). Sparse arrays need fewer sensor elements than uniform linear arrays (ULAs) to realize a given aperture. Alternately, for a given number of sensors, sparse arrays provide larger apertures and hi...
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Many modern smart devices are equipped with a microphone array and a loudspeaker (or are able to connect to one). Acoustic echo cancellation algorithms, specifically their multi-microphone variants, are essential components in such devices. On top of acoustic echos, other commonly encountered interference sources in telecommunication systems are re...
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A miniature deformable squama mechanics based on piezoelectric actuation inspired by the deformable squama is proposed in this paper. The overall size of the mechanics is 16 mm × 6 mm × 6 mm, the weight is only 140 mg, the deflection angle range of the mechanical deformation is −15°~45°, and the mechanical deformation is controllable. The small-bat...
Preprint
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Nonlinear, stochastic high-resolution methods for bearing estimation in array processing can become unreliable in the presence of model errors and correlated noise. Simulations revealed that this instability cannot be removed through standard prewhitening based on a noise model. The "sector-focused stability" (SFS) method described in this note use...
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We develop a linear inversion technique for measuring the modal composition and directionality of ambient seismic noise. The technique draws from similar techniques used in astrophysics and gravitational-wave physics, and relies on measuring cross-correlations between different seismometer channels in a seismometer array. We characterize the sensit...
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The multidecadal fluctuations in sea level changes play an important role in the exact quantification of present-day global mean sea level (GMSL) rise and its acceleration. Here, we use an array processing technique (optimal sequence estimation) to analyze 44 global tide gauge (TG) sea level records with identical 1933/01-2019/12 data spans. The re...
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Beamforming is a type of audio array processing techniques used for interference reduction, sound source localization, and as pre-processing stage for audio event classification and speaker identification. The auditory scene analysis community can benefit from a systemic evaluation and comparison between different beamforming techniques. In this pa...
Preprint
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The rule for optimal linear detection of a signal in additive correlated noise is "prewhiten, then match". Dealing with noise in high-resolution signal processing is more complicated. For example, the signal-to-noise level affects resolution, which is not the case for linear methods. Bearing estimation in sensor array processing is based on estimat...
Article
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Optically pumped magnetometers (OPMs) are quickly widening the scopes of noninvasive neurophysiological imaging. The possibility of placing these magnetic field sensors on the scalp allows not only to acquire signals from people in movement, but also to reduce the distance between the sensors and the brain, with a consequent gain in the signal-to-n...
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In recent years, deep learning has been used extensively in a wide range of fields. In deep learning, Convolutional Neural Networks (CNN) are found to give the most accurate results in solving real world problems such as several engineering fields, including array processing, wireless communications, medical signal processing, speech processing and...
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Energy efficient array processing is critical to implement feasible solutions for directional communication in a mmWave channel. MmWave channels are highly susceptible to blockage and require frequent angle of arrival (AoA) estimation. An AoA estimation solutions with a fully digital architecture offers a low latency, high performance and flexible...
Article
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Radiative (or far-field) energy replenishment for devices such as smartphones, laptops, robots, and small electric appliances paves the way to autonomous and continuous devices functioning, thus bypassing the need of operation interruptions, human maintenance activities, and replenishment by wired transformers. In this work, we investigate the feas...
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On November 15, 2017, an event related to the disappearance of the Argentine military submarine ARA San Juan was detected by two hydrophone triplet stations of the IMS network, established to enforce the nuclear test ban treaty (CTBT). From the two direct hydroacoustic arrivals recorded at 6000 and 8000 km from the localized wreckage, calculated lo...
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Digital image data processing is mainly to input digital image data into a computer to complete the conversion of a continuous spatially distributed image model into a discrete digital model so that the computer can identify, process, and store the processing process of digital image information. Geographic information system (GIS) is a computer sy...
Article
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The Kalman filter (KF) loses its optimality properties when the system model is misspecified to a certain extent, that is, when the assumed system knowledge does not perfectly match the true system dynamics, which in turn can severely impact its performance in real-life applications. The same goes for its extended counterpart (EKF). Linear constrai...
Preprint
Full-text available
The phase-velocity dispersion curve (DC) is an important characteristic of the propagation of surface waves in sedimentary environments. Although the procedure for DC estimation in onshore environments using ambient vibration recordings is well established, the DC estimation in offshore environments using arrays of Ocean Bottom Seismometers (OBS) p...
Article
Full-text available
Horizontal slowness vector measurements using array techniques have been used to analyse many Earth phenomena from lower mantle heterogeneity to meteorological event location. While providing observations essential for studying much of the Earth, slowness vector analysis is limited by the necessary and subjective visual inspection of observations....
Article
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Infrasound array processing is applied to monitor and characterize atmospheric explosions in the context of the Comprehensive Nuclear‐Test‐Ban Treaty. Anyhow, for many infrasound sources the exact location and time are initially unknown and sometimes difficult to precisely estimate afterwards. In contrast, rocket launches are well‐defined ground‐tr...
Article
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The versatility and cost-efficiency of fibre-optic Distributed Acoustic Sensing (DAS) technologies facilitate geophysical monitoring in environments that were previously inaccessible for instrumentation. Moreover, the spatio-temporal data density permitted by DAS naturally appeals to seismic array processing techniques, such as beamforming for sour...