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Incorporation of aircraft orientation into automatic target recognition using passive radar

IET RADAR SONAR AND NAVIGATION 2020年第7期14卷 1079-1087页

作者： Ehrman, Lisa M. Lanterman, Aaron D. 4M Res Inc 675 Discovery Dr NW 302 Huntsville AL 35806 USA Georgia Inst Technol Sch Elect & Comp Engn Mail Code 0250 Atlanta GA 30332 USA

Most research regarding passive radar exploiting 'illuminators of opportunity', such as FM radio, has focused on detecting and tracking targets. This study explores adding automatic target recognition (ATR) capabilities to such systems. The ATR algorithms described here use the radar cross-section (RCS) of potential targets, collected over a short period of time. The received signal model accounts for aircraft position and orientation, propagation losses, and antenna gain patterns. One proposed algorithm uses a coordinated flight model to estimate aircraft orientations, while a more sophisticated algorithm uses an extended Kalman filter to estimate the target orientations along with measures of uncertainty in those estimates. In both cases, the orientations are estimated using velocity measurements obtained from a tracking algorithm. The radar return of each aircraft in the target library is simulated as though each is executing the same manoeuvre as the target detected by the system. To improve the robustness of the result, the more sophisticated algorithm jointly optimises over feasible orientation profiles and target types via dynamic programming.

关键词： passive radar target tracking radar detection radar cross-sections radar target recognition radar signal processing radar tracking Kalman filters dynamic programming radar antennas velocity measurement nonlinear filters aircraft orientation passive radar exploiting illuminators FM radio target tracking automatic target recognition capabilities ATR algorithms radar cross-section potential targets signal model accounts aircraft position propagation losses antenna gain patterns flight model extended Kalman filter target orientations tracking algorithm radar return target library feasible orientation profiles target types dynamic programming

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Improving MIMO-OFDM decision-directed channel estimation by utilizing error-correcting codes

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ADVANCES IN RADIO SCIENCE 2009年 7卷 83-88页

作者： Beinschob, P. Lieberei, M. Zoelzer, U. Univ Fed Armed Forces Hamburg Dept Signal Proc & Commun Helmut Schmidt Univ Hamburg Germany

In this paper a decision-directed Multiple-Input Multiple-Output (MIMO) channel tracking algorithm is enhanced to raise the channel estimate accuracy. While DDCE is prone to error propagation the enhancement employs channel decoding in the tracking process. Therefore, a quantized block of symbols is checked on consistency via the channel decoder, possibly corrected and then used. This yields a more robust tracking of the channel in terms of bit error rate and improves the channel estimate under certain conditions. Equalization is performed to prove the feasibility of the obtained channel estimate. Therefore a combined signal consisting of data and pilot symbols is sent. Adaptive filters are applied to exploit correlations in time, frequency and spatial domain. By using good error-correcting coding schemes like Turbo Codes or Low Density Parity Check (LDPC) codes, adequate channel estimates can be acquired even at low signal to noise ratios (SNR). The proposed algorithm among two others is applied for channel estimation and equalization and results are compared.

关键词： .Parity error-correcting tracking algorithm channel estimate DDCE Improving MIMO-OFDM decision-directed

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Fusion detection in time-lapse microscopy images: application to lipid droplets coalescence in plant seeds

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IFAC-PapersOnLine 2016年第26期49卷 239-244页

作者： Deslandes, François Laroche, Béatrice Trubuil, Alain MaIAGE INRA Université Paris-Saclay Jouy-en-Josas78350 France

Detecting fusion events between lipid droplets of Arabidopsis thaliana embryos is of significant interest to understand the role of lipid droplet proteins. Lipid droplet proteins, called oleosins, have been shown to influence the size of lipid droplets possibly by preventing coalescence. We propose to detect fusion events in timelapse microscopy images of several oleosin deficient A. thaliana embryos. To detect volume preserving fusion events in a dense environment, we propose a procedure based on particle tracking and statistical tests. Using synthetic data, we compare the performances of our method to heuristic decision rules adapted from tracking algorithms from the literature. © 2016

关键词： Image fusion Cytology Drops Heuristic algorithms Heuristic methods Image analysis Microscopic examination Plants (botany) Proteins Seed Arabidopsis thaliana Cell biology Event detection Heuristic decisions Multi target tracking Time lapse microscopy tracking algorithm Volume preserving

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AN ANTENNA tracking METHOD FOR LAND-MOBILE SATELLITE-COMMUNICATIONS SYSTEM

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ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 1995年第9期78卷 91-102页

作者： YAMAMOTO, S TANAKA, K WAKANA, H OHMORI, S MINIST POSTS & TELECOMMUN COMMUN RES LAB KOGANEI TOKYO 184 JAPAN

A new satellite-tracking method is proposed for a directional antenna installed on a car for L-band land-mobile satellite communication. This method uses both a fiber optic gyroscope (FOG) and a magnetic compass (MC) with an open-loop control algorithm, which compensates for the disadvantages of individual sensors. Since FOG can detect the angular velocity precisely but cannot detect the absolute azimuthal direction, this type of sensor has inherent errors due to accumulating the angular velocities necessary to obtain the azimuthal direction. Cumulative errors caused mainly by a disagreement between the FOG axis for measuring rotation and the vertical axis during turning curves can be compensated by MC. The disadvantage of MC is that errors due to magnetic disturbance are caused by magnetized bridges and trucks. In the proposed method, the occurrence of a magnetic disturbance is detected from a statistical analysis of MC acquired data and FOG is used to control the antenna direction when a car turns either right or left. According to an analysis of the three-dimensional motions of cars, it was determined that only azimuthal antenna tracking can provide the precise control required to obtain good tracking performance, even when using an L-band directional antenna with an antenna gain of approximately 13 dBi.

关键词： MOBILE SATELLITE COMMUNICATIONS ANTENNA tracking OPEN-LOOP CONTROL tracking algorithm FIBER OPTIC GYROSCOPE

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Structure, characteristics, and simulation of monsoon low-pressure systems in CFSv2 coupled model

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JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 2017年第8期122卷 6394-6415页

作者： Srivastava, Ankur Rao, Suryachandra A. Rao, D. Nagarjuna George, Gibies Pradhan, Maheswar Indian Inst Trop Meteorol Pune Maharashtra India Savitribai Phule Pune Univ Dept Atmospher & Space Sci Pune Maharashtra India

Indian Summer Monsoon (ISM) synoptic scale systems (low-pressure systems, LPS) are known to produce increased rainfall over central India (CI). Fidelity of the Climate Forecast System version 2 (CFSv2) at simulating the LPS and their characteristics is evaluated in this study using a feature tracking algorithm. The model is able to reproduce the clustering of LPS by monsoon intraseasonal oscillations and the associated precipitation over eastern-central India. It is found that mean biases in circulation and moisture stem from cold sea surface temperature (SST) bias in the model which results in weak LPS linked rainfall events over central India. Two sensitivity experiments were carried out to study the effect of coupled dynamics of tropical basins on LPS. Suppression of active dynamics of the tropical Indian Ocean in CFSv2 causes a reduction in cold SST bias and enhanced cyclogenesis in the northern Bay of Bengal. The reduced low-level anticyclonic bias and enhanced moisture availability result in a better simulation of LPS structure, and associated precipitation over CI. Suppression of active ocean dynamics in tropical Pacific Ocean causes a perennial El-Nino type bias which restricts LPS propagation over the Indian landmass, possibly due to time-mean subsidence induced by remote El-Nino forcing. Sensitivity experiments indicate the need for improvements in the representation of tropical Indian Ocean coupled dynamics as well as convective parameterization schemes in the model for subsequent improvements in the simulation of ISM at various time scales.

关键词： monsoon low-pressure systems coupled dynamics tracking algorithm CFSv2

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Toward a Multi-Decadal Climatology of North Pacific Polar Lows Employing Dynamical Downscaling

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TERRESTRIAL ATMOSPHERIC AND OCEANIC SCIENCES 2012年第3期23卷 291-301页

作者： Chen, Fei Geyer, Beate Zahn, Matthias von Storch, Hans Helmholtz Zentrum Geesthacht Inst Coastal Res Berlin Germany Univ Reading Reading Berks England

The North Pacific is an area where sub-synoptic Polar Lows frequently form during the cold season, especially over the Bering Sea, Gulf of Alaska and Japan Sea. So far, a multi-decadal climatology of such Polar Lows based on individual cases has not been assembled. Here, we consider dynamical downscaling method for realistically constructing the formation and life cycles of such lows over the past 6 decades without exploiting sub-synoptic information in initial fields. To do so, a regional climate model is conditioned by large-scale information of NCEP re-analyses. We test the approach by examining its skill in simulating ten known cases of North Pacific Polar Lows. Three of these are discussed in some detail. The signatures of all storms emerge in the simulations with additional sub-synoptic details. The tracks of the simulated Polar Lows closely follow the tracks derived from satellite imagery. We conclude that the suggested method is suitable for constructing multi-decade climatologies, including trends and variability, of Polar Lows in the North Pacific by dynamically downscaling NCEP re-analyses.

关键词： North Pacific Polar Low Downscaling tracking algorithm Regional climate modeling

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Life Cycle of Atmospheric Rivers: Identification and Climatological Characteristics

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JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 2018年第22期123卷 12715-12725页

作者： Zhou, Yang Kim, Hyemi Guan, Bin SUNY Stony Brook Sch Marine & Atmospher Sci Stony Brook NY 11794 USA Univ Calif Los Angeles Joint Inst Reg Earth Syst Sci & Engn Los Angeles CA USA CALTECH Jet Prop Lab Pasadena CA USA

An atmospheric river (AR) event is a strong poleward moisture transport that is composed of a series of spatiotemporally connected instantaneous AR objects. A new object-based tracking algorithm is developed in this study, which aims to identify an AR event and investigate its life cycle from origin to termination. The algorithm identifies duration, intensity, propagation speed and direction, and the traveled distance throughout the life cycle of the AR event. The tracking algorithm is applied to 6-hourly column-integrated water vapor flux from November to March during the period of 1979-2017, with a focus on the North Pacific. Most North Pacific AR events originate in the subtropics over the Northwest Pacific and terminate at higher latitudes over the Northeast Pacific including western North America. On average, long AR events that last more than 72 hrs travel 7 times longer in distance and have stronger intensity than short AR events that last less than 24 hrs. Finally, a new accumulated AR intensity index is developed, which summarizes the overall impact of AR events over a given domain during a certain period by incorporating number, lifetime, and intensities of AR events. Plain Language Summary Atmospheric rivers (ARs) are " rivers" in the sky that transport water vapor from the tropics to higher latitudes. ARs play an important role in water resources because they transport as much water as the largest rivers on the ground and can often induce extreme precipitation when making landfall. A technique is developed to numerically detect and track ARs as they propagate in time and space. Based on this technique, we study the climatological characteristics of the life cycle (i. e., from appearance to disappearance) of winter ARs over the North Pacific. Most of the ARs originate at about 25 degrees N over the Northwest Pacific and terminate between 50 degrees N and 60 degrees N over the Northeast Pacific. We also found that longer-lived ARs can travel 7 seven times

关键词： atmospheric rivers life cycle tracking algorithm

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Exploring Blob Detection to Determine Atomic Column Positions and Intensities in Time-Resolved TEM Images with Ultra-Low Signal-to-Noise

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MICROSCOPY AND MICROANALYSIS 2022年第6期28卷 1917-1930页

作者： Manzorro, Ramon Xu, Yuchen Vincent, Joshua L. Rivera, Roberto Matteson, David S. Crozier, Peter A. Arizona State Univ Sch Engn Matter Transport & Energy Engn G Wing 301501 E Tyler Mall Tempe AZ 85287 USA Cornell Univ Dept Stat & Data Sci Ithaca NY USA Univ Puerto Rico Dept Math Sci Mayaguez PR USA

Spatially resolved in situ transmission electron microscopy (TEM), equipped with direct electron detection systems, is a suitable technique to record information about the atom-scale dynamics with millisecond temporal resolution from materials. However, characterizing dynamics or fluxional behavior requires processing short time exposure images which usually have severely degraded signal-to-noise ratios. The poor signal-to-noise associated with high temporal resolution makes it challenging to determine the position and intensity of atomic columns in materials undergoing structural dynamics. To address this challenge, we propose a noise-robust, processing approach based on blob detection, which has been previously established for identifying objects in images in the community of computer vision. In particular, a blob detection algorithm has been tailored to deal with noisy TEM image series from nanoparticle systems. In the presence of high noise content, our blob detection approach is demonstrated to outperform the results of other algorithms, enabling the determination of atomic column position and its intensity with a higher degree of precision.

关键词： atomic columns blob detection nanoparticles noisy time-resolved TEM tracking algorithm transmission electron microscopy

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Crop stem detection and tracking for precision hoeing using deep learning

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COMPUTERS AND ELECTRONICS IN AGRICULTURE 2022年 192卷 106606-106606页

作者： Lac, Louis Da Costa, Jean-Pierre Donias, Marc Keresztes, Barna Bardet, Alain Univ Bordeaux IMS UMR 5218 F-33405 Talence France CNRS IMS UMR 5218 F-33405 Talence France CTIFL 28 Route Nebouts F-24130 Prigonrieux France

Developing alternatives to the chemical weeding process usually carried out in vegetable crop farming is necessary in order to reach a more sustainable agriculture. However, a precise mechanical weeding requires specific sensors and advanced computer vision algorithms to process crop and weed discrimination in real-time. In this paper we propose an algorithm able to detect, locate, and track the stem position of crops in images which is suitable for precision actions in vegetable fields such as mechanical hoeing within crop rows. The algorithm is twofold: (i) a deep neural network for object detection is first used to detect crop stems in individual RGB images and then (ii) an aggregation algorithm further refines the detections taking advantage of the temporal redundancy in consecutive frames. We evaluated the pipeline on images of maize and bean crops at an early stage of development, acquired in field conditions with a camera embedded in an experimental mechanical weeding system. We reported Fl-scores of respectively 94.74% and 93.82% with a location accuracy around 0.7 cm when compared with human annotation. Moreover, this pipeline can operate in real-time on an embedded computer consuming as little power as 30 W.

关键词： Precision agriculture Deep learning Neural network Object detection tracking algorithm

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Single-cell tracking with Compton-PET: An in silico feasibility study

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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 2023年 1053卷

作者： Ghosh, S. Das, P. Indian Inst Technol Dept Phys Mumbai 400076 Maharashtra India

The tracking of single cells is a critical component of developing new therapeutic techniques, particularly for metastatic cancer cells, immune cells, and stem cells. To achieve this, various types of scanners, such as PET, MRI, fluorescence imaging, and optical imaging, are used. In this study, we evaluated the feasibility of using the Compton-PET system for single-cell tracking. Unlike conventional PET scanners that consist of a single detector ring, the Compton-PET system comprises an additional scatterer ring within the primary absorber ring. This design enables the acquisition of both double and single events simultaneously, where doubles refer to the detection of both annihilation photons in either of the two rings, and singles refer to the detection of only one photon scattered in the scatterer detector and subsequently absorbed in the absorber detector. This study is simulation-based. We propose utilising both doubles and singles events to track the unknown trajectory of single cells in the Compton-PET system. We investigated a range of velocities and activities of single cells and compared the tracking performance of the Compton-PET and PET scanners. Our findings indicate that the use of doubles and singles events together in Compton-PET improves the tracking performance compared to PET scanners.

关键词： Nuclear medicine Compton camera tracking algorithm Monte Carlo simulations

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