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Semantic and context features integration for robust object tracking

IET IMAGE PROCESSING 2022年第5期16卷 1268-1279页

作者： Yao, Jinzhen Zhang, Jianlin Wang, Zhixing Shao, Linsong Chinese Acad Sci Key Lab Opt Engn Chengdu Peoples R China Chinese Acad Sci Inst Opt & Elect Chengdu 610200 Peoples R China Univ Chinese Acad Sci Sch Elect Elect & Commun Engn Beijing Peoples R China

Siamese network-based object tracking learns features of a target object marked in the first frame and that of the object in subsequent frames simultaneously and then measures similarity between two features to recognize and locate the object. Owing to their efficiency and high accuracy, Siamese networks have attracted much attention recently. However, tracking accuracy decreases significantly when there are scale changes, occlusion, and pose variations due to the way that Siamese networks estimate feature similarity. To address this issue, the authors propose a tracking algorithm, named Semantic and context features integration for robust object tracking that integrates local and global features of the object. Local features provide context information for tracking parts of the object, while global features contain semantic information for tracking the object. The authors meticulously design local and global classification and regression heads and integrate them into one uniform framework to achieve integration tracking. This method effectively alleviates low accuracy in complex scenes such as scale changes, deformation, and occlusion. Numerous experiments demonstrate that this method achieves state-of-art (SOTA) performance with 45 FPS on a single RTX2060 Super GPU on public tracking datasets, including VOT2016, VOT2019, OTB100, GOT-10k, and LaSOT, and its effectiveness and efficiency is confirmed.

关键词： subsequent frames global classification regression analysis regression heads local features object tracking scale changes target object image representation learning (artificial intelligence) robust object tracking semantic information target tracking feature extraction global features Siamese network-based object tracking tracking accuracy tracking algorithm integration tracking Semantic context features integration context information object detection public tracking datasets feature similarity Siamese networks image classification

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Characteristic Changes in the Strengthening Western Disturbances over Karakoram in Recent Decades

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ASIA-PACIFIC JOURNAL OF ATMOSPHERIC SCIENCES 2024年第3期60卷 255-270页

作者： Javed, Aaquib Kumar, Pankaj Indian Inst Sci Educ & Res Bhopal Dept Earth & Environm Sci Bhopal Bypass Rd Bhopal 462066 India

Western disturbances (WDs) are upper-tropospheric mid-latitude synoptic systems propagating eastward along the subtropical westerly jet stream. They are capable of causing extreme precipitation events and have strengthened their impact over the Karakoram part of the Himalayas in recent decades. They play a crucial role in the sustenance of the "Karakoram Anomaly," which refers to the anomalous stability/surge of a few Karakoram glaciers in contrast to the other glaciers of the Himalayas. Using the existing WD-catalog derived from ERA5 and MERRA2 reanalysis datasets, we observed that the core genesis zone for Karakoram WDs had undergone a statistically significant shift of similar to 9.7 degrees E, migrating towards more favourable conditions for cyclogenesis. The study proposes a new parameter to identify regions of potential extratropical cyclogenesis. The shift can be attributed to an enhanced genesis potential, convergence, and higher moisture availability along the WD path. Composite analysis suggests that moisture availability has risen significantly over the shifted zone. Moreover, the propagation speeds of these systems have significantly declined, which explains the recent intensification of precipitation events related to WDs over the Karakoram and hints toward a crucial synoptic influence on the anomalous regional mass-balance phenomenon.

关键词： Western disturbances Karakoram anomaly Climate change tracking algorithm

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Machine learning and dynamics based error-index method for the detection of monsoon onset vortex over the Arabian Sea: Climatology and composite structures

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QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 2023年第751期149卷 537-555页

作者： Sasanka, Talukdar Osuri, Krishna K. Niyogi, Dev Natl Inst Technol Rourkela Dept Earth & Atmospher Sci Rourkela India Univ Texas Austin Jackson Sch Geosci Dept Geol Sci Austin TX USA Univ Texas Austin Dept Civil Architectural & Environm Engn Austin TX USA Natl Inst Technol Rourkela Dept Earth & Atmospher Sci Rourkela 769008 Odisha India

Monsoon onset vortex (MOV) forms over the Arabian Sea near the northern flank of the low-level jet during the monsoon onset over Kerala (MOK). The study concerns the development and evaluation of an algorithm for detecting and tracking MOVs in regional/global analyses. The first step involves preparing the first-guess database of MOV locations based on geopotential height, surface and 850 hPa wind magnitude and circulation from ERA5 reanalysis for 1982-2020. Three different approaches: (a) error-index of MOV, (b) machine-learning (ML), and (c) combination of error-index and ML models, are employed to detect MOV. The error-index method, in which the detected vortex is compared with the idealized vortex, achieves an accuracy of 0.6 with a 0.95 true-positive-rate and 0.55 false-positive-rate. The best ML models can identify the MOVs in the training samples with maximum accuracy of 0.99. However, their accuracy is limited in tracking the MOVs continuously in the global analyses as they are not trained with wind circulation. The combined error-index and ML models could detect all the 27 observed MOVs in the ERA5 reanalysis with 5 false-positives. This approach is tested on IMDAA reanalysis, and the success rate is 0.79 with 6 false-positives. Temporal analyses show that similar to 95% of the MOVs occur during -10 to +20 days from MOK. Composite structures indicate that the MOVs exhibit higher sea-surface temperatures (> 0.3 ?) in the forward sector with 85% cloud cover in the left-rear sector. Rainfall of 4-5 mm center dot hr(-1) is seen in the left sector. Upper-level (700-200 hPa) warm core (> 3.5?) and lower-level (1000-700 hPa) cold-core (< 1?) is evident. The composite structures of MOVs are almost similar to that of monsoon depressions with higher asymmetry in the forward-rear sectors. This study may help explore future projections of MOV activity from climate models and its relationship with monsoon rainfall activity.

关键词： Arabian Sea composite structure machine learning monsoon onset vortex tracking algorithm

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Non-Cooperative Target Positioning and tracking algorithm Based on Bearings Only Measurement 6

Non-Cooperative Target Positioning and Tracking Algorithm Ba...

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IEEE Chinese Guidance, Navigation and Control Conference (CGNCC)

作者： Sun, S. M. Zhang, D. B. Li, H. N. Qian, S. Xian Satellite Control Ctr State Key Lab Astronaut Dynam Xian 710043 Peoples R China

ISBN: (纸本)9781479946990

With the vigorous development of space technology, positioning and tracking of non-cooperative target become an important problem within the domain of space surveillance and safety. Because of the perturbation effect, orbital plane changes with time in the inertia frame, then the real position and velocity vector beyond the plane which is spanned by initial position and velocity, so the classical Laplace model is not suit for the dynamics model with perturbation forces. With consideration of perturbation effect on the normal direction of orbit plane, in this paper, the Laplace model of spacecraft motion was extended and founded in the space which is spanned by position vector, velocity vector and the multiplication cross vector of both, then a new tracking algorithm of non-cooperative target was studied based on bearings only measurement. Results show that non-cooperative target could be well tracked and positioned only with bearings measurement when the number of tracking devices is equal to or greater than two, so the new method could be used in the domain of space surveillance and invade target early warning.

关键词： Laplace transforms position control space vehicles target tracking vectors Laplace model bearings only measurement multiplication cross vector noncooperative target positioning algorithm position vector spacecraft motion tracking algorithm velocity vector Extraterrestrial measurements Noise measurement Position measurement Radar tracking Space vehicles Target tracking Vectors

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The decline in western disturbance activity over Northern India in recent decades

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CLIMATIC CHANGE 2023年第7期176卷 1-22页

作者： Javed, Aaquib Anshuman, Katyan Kumar, Pankaj Sachan, Disha Indian Inst Sci Educ & Res Bhopal Dept Earth & Environm Sci Bhopal By Pass Rd Bhopal 462066 India

Western disturbances (WDs) are upper-tropospheric synoptic-scale cyclonic storms that travel eastwards embedded in the subtropical westerly jet stream. They are of veritable significance to the sustenance of the population in the north and northwest regions of the Indian subcontinent and are often harbingers of extreme precipitation events during the boreal winter. This study utilizes a tracking algorithm with the upper-level vorticity field of the ERA5 reanalysis product to catalog events over the northern part of the Indian subcontinent for 39 WD seasons (Nov-Mar;1980-2019), including information about their trajectory and precipitation. The contribution of WDs to the region's total precipitation has been quantified comprehensively, enabling the proposition of a "core WD zone" and an intensity categorization of WDs affecting India. The core zone exhibits a decreasing trend for annual WD-associated precipitation despite the frequency of storms depicting no evident trend. The combined mean frequency of strong and extreme WDs declined by as much as similar to 43%, contrary to the mean occurrences of feeble and moderate WDs, which rose by similar to 11%. However, the mean seasonal precipitation volume decreased for all the categories, irrespective of the changes in their frequencies. The sharpest decline (similar to 49%) was observed for the most intense WDs (strong and extreme), primarily explaining the decreasing WD precipitation intensity across the core WD zone. The spatial distribution and evolution of various dynamical parameters reveal an inhibitive dynamic state of the atmosphere restricting the moisture advection capacity of WDs and the resultant decline in the associated precipitation over the core WD zone in recent decades.

关键词： Western disturbances Climate change tracking algorithm

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Examination of Cinnamomum camphora interlocked grain adopting X-ray computed tomography combined with particle image velocimetry

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JOURNAL OF WOOD SCIENCE 2022年第1期68卷 1-10页

作者： Cipta, Hairi Kobayashi, Kayoko Chen, Shuoye Sugiyama, Junji Kyoto Univ Grad Sch Agr Sakyo Ku Kyoto 6068502 Japan

Trees develop wood grain more or less parallel to the tree axis as they grow laterally. However, many tree species also develop interlocked grain that is expressed as a change in the wood grain orientation, periodically switching between left- and right-handed spirals over the years. Wood grain information is critical to determining the wood quality and is an important record of cellular events in a cambium. This study examined the wood grain of axial xylem cells in the semi-ring porous hardwood Cinnamomum camphora by first visualizing the three-dimensional structure using a conventional X-ray computed tomography instrument producing tomography images. We propose the use of particle image velocimetry (PIV) and the two-dimensional fast Fourier transform (2D-FFT) to analyze computed tomography images in obtaining grain angle (delta) information from the vessel deviation. We found undulation on the radial variation of the grain angle (delta) that indicates periodical changes in the wood grain orientation as left- and right-handed spirals ranging from - 25 degrees to 16 degrees and - 22 degrees to 18 degrees using the 2D-FFT and PIV, respectively. Furthermore, despite the major orientation of vessels inclining in the tangential direction, the PIV result revealed a minor deviation with vessels inclining in various orientations along the tree radius.

关键词： Grain angle Image analysis tracking algorithm Vessel network Water transport

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tracking structure suitable for L6 signal

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The Journal of China Universities of Posts and Telecommunications 2021年第4期28卷 64-74页

作者： Wang Yiting Ba Xiaohui Liu Xueyong Yang Ying Li Jian Chen Jie System on Chip Lab Institute of Microelectronics of the Chinese Academy of SciencesBeijing 100029China College of Electronic and Electrical Communication Engineering University of Chinese Academy of SciencesBeijing 100049China

A tracking structure suitable for L6 signal of quasi-zenith satellite system(QZSS) was proposed in order to track the L6 signal without other frequency assistance. Moreover, the tracking structure does not change the receiver’s hardware structure. The main difference between the proposed and the traditional tracking structure lies in the generation of local codes of E,P and L branches. The method of local code generation is designed in a two-stage manner. The first stage is the generation of the P branch local code with fast fouriertransform(FFT). In the second stage, the local codes of the E and L branches are obtained with the code-chip interval. The tracking structure can track and decode L6 signal separately, and track code shift keying(CSK)modulated signal as well. The structure was verified using both simulation data, generated in different conditions, and actual data obtained from QZSS satellites respectively. The results show that the improved tracking loop is able to track L6 signal without other frequency assitance. Furthermore, the biterror ratio(BER) of L6 tracking algorithm is lower than that of L1C/A assist L6 algorithm, when the Doppler remains a constant and reed solomn(RS)encode are applied. To be more specific, with the proposed structure the BER decreased by 11.40%, 17.07%, 15.00%, 11.15%, 5.19% when carrier to noise ratio(CNR) is 36-40 dB·Hz.

关键词： quasi-zenith satellite system L6 signal code shift keying modulation tracking algorithm

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Electric Arc Length Control of Circular Seam in Welding Robot Based on Arc Voltage Sensing

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IEEE SENSORS JOURNAL 2022年第4期22卷 3326-3333页

作者： Lei, Ting Wu, Chaoqun Yu, Huiwen Wuhan Univ Technol Sch Mech & Elect Engn Wuhan 430070 Peoples R China

Arc length control plays an important role in improving welding quality, especially for tube-to-tubesheet welding with numerous and dense circular seams. The difficulty of arc length control lies not only in acquisition and processing of arc voltage signal, but also in designing reasonable tracking algorithm and control method. This paper proposes an arc voltage tracking system with a self-developed arc voltage module for orbiting robotic welding. A real-time arc voltage tracking algorithm based on direct current (DC) pulse square-wave is proposed, and a two-dimension and three-section fuzzy controller are also presented. The experimental results show that the maximum peak voltage (PV) decreases from 13.92 V (circular seam A) to 13.44 V (circular seam B). The surface morphology of circular seam B with arc voltage tracking is obviously superior than that of circular seam A without arc voltage tracking. The arc voltage tracking method proposed in this manuscript has an active influence on welding quality.

关键词： Welding Voltage control Voltage Sensors Tungsten Robots Electrodes Arc voltage tracking welding robot circular seam 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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Wide-Angle Vital Signs Measurements by Adaptive FMCW Radar

Wide-Angle Vital Signs Measurements by Adaptive FMCW Radar

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IEEE MTT-S International Microwave Biomedical Conference (IMBioC)

作者： Mehrjouseresht, Pouya Babarinde, Oluwatosin J. El Hail, Reda Schreurs, Dominique M. M. -P. Katholieke Univ Leuven Dept Elect Engn Div ESAT WAVECORE Leuven Belgium DTAI FET Flanders Make Leuven Belgium Katholieke Univ Leuven Leuven AI DTAI Dept Comp Sci Geel Belgium

ISBN: (纸本)9781665492171

This paper demonstrates the use of a people tracking algorithm and beamforming technique in monitoring vital signs for smart home applications. A person's location and velocity are detected. When the person remains stationary within a specific area (distance and angle), the radar beam is steered towards the target, and vital signs are measured. The advantage of this approach is not only the physiological parameters can be monitored in different positions by steering the transmitted signals towards the target's location, but also the target's range bin can be recognized clearly from other clutter according to its amplitude. To extract vital signs, the received signals from two receiver channels are combined. An algorithm based on continuous wavelet transform (CWT) with different mother wavelets is applied to the phase of the combined signal. The experimental results demonstrate that the proposed algorithm can monitor breathing and heart rate with a maximum error of 10.7% and 11.51%, respectively, within a range of 1 to 2 meters and an angle from -40 to 40 degrees.

关键词： FMCW radar Vital signs Beam steering tracking algorithm Smart home

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