Track Reconstruction Research Articles

A full 3D reconstruction of rail tracks using a camera array

This research addresses limitations found in existing 3D track reconstruction studies, which often focus solely on specific rail sections or encounter deployment challenges with rolling stock. To address this challenge, we propose an innovative solution: a rolling-stock embedded arch camera array scanning system. The system includes a semi-circumferential focusing vision array, an arch camera holder, and a Computer Numerical Control machine to simulate track traverse. We propose an optimal configuration that balances accuracy, full rail coverage, and modelling efficiency. Sensitivity analysis demonstrates a reconstruction accuracy within 0.4 mm when compared to Lidar-generated ground truth models. Two real-world experiments validate the system's effectiveness following essential data preprocessing. This integrated technique, when combined with rail rolling stocks and robotic maintenance platforms, facilitates swift, unmanned, and highly accurate track reconstruction and surveying.

Quantum Algorithms for Charged Particle Track Reconstruction in the LUXE Experiment

The LUXE experiment is a new experiment in planning in Hamburg, which will study quantum electrodynamics at the strong-field frontier. LUXE intends to measure the positron production rate in this unprecedented regime using, among others, a silicon tracking detector. The large number of expected positrons traversing the sensitive detector layers results in an extremely challenging combinatorial problem, which can become computationally expensive for classical computers. This paper investigates the potential future use of gate-based quantum computers for pattern recognition in track reconstruction. Approaches based on a quadratic unconstrained binary optimisation and a quantum graph neural network are investigated in classical simulations of quantum devices and compared with a classical track reconstruction algorithm. In addition, a proof-of-principle study is performed using quantum hardware.

NeuroZoom: Denoising and Super Resolving Neuromorphic Events and Spikes.

Neuromorphic cameras are emerging imaging technology that has advantages over conventional imaging sensors in several aspects including dynamic range, sensing latency, and power consumption. However, the signal-to-noise level and the spatial resolution still fall behind the state of conventional imaging sensors. In this paper, we address the denoising and super-resolution problem for modern neuromorphic cameras. We employ 3D U-Net as the backbone neural architecture for such a task. The networks are trained and tested on two types of neuromorphic cameras: a dynamic vision sensor and a spike camera. Their pixels generate signals asynchronously, the former is based on perceived light changes and the latter is based on accumulated light intensity. To collect the datasets for training such networks, we design a display-camera system to record high frame-rate videos at multiple resolutions, providing supervision for denoising and super-resolution. The networks are trained in a noise-to-noise fashion, where the two ends of the network are unfiltered noisy data. The output of the networks has been tested for downstream applications including event-based visual object tracking and image reconstruction. Experimental results demonstrate the effectiveness of improving the quality of neuromorphic events and spikes, and the corresponding improvement to downstream applications with state-of-the-art performance.

Performance of the reconstruction of large impact parameter tracks in the inner detector of ATLAS

Searches for long-lived particles (LLPs) are among the most promising avenues for discovering physics beyond the Standard Model at the Large Hadron Collider (LHC). However, displaced signatures are notoriously difficult to identify due to their ability to evade standard object reconstruction strategies. In particular, the ATLAS track reconstruction applies strict pointing requirements which limit sensitivity to charged particles originating far from the primary interaction point. To recover efficiency for LLPs decaying within the tracking detector volume, the ATLAS Collaboration employs a dedicated large-radius tracking (LRT) pass with loosened pointing requirements. During Run 2 of the LHC, the LRT implementation produced many incorrectly reconstructed tracks and was therefore only deployed in small subsets of events. In preparation for LHC Run 3, ATLAS has significantly improved both standard and large-radius track reconstruction performance, allowing for LRT to run in all events. This development greatly expands the potential phase-space of LLP searches and streamlines LLP analysis workflows. This paper will highlight the above achievement and report on the readiness of the ATLAS detector for track-based LLP searches in Run 3.

Measurement of cross section for the 232Th(n, f) reaction using a time projection chamber

Accurate cross sections of neutron induced fission reactions are needed in the development of nuclear science and technology. The time projection chamber (TPC) is viewed as the potential detector to improve the measurement accuracy of the fission cross sections based on its track reconstruction and particle identification capabilities. The TPC developed by the back-streaming white neutron source (Back-n) team of China Spallation Neutron Source (CSNS) was introduced to verify its ability in measuring the cross section of fission reaction. Using our TPC, and based on the mono-energetic neutron source at Peking University and 232Th/238U samples, we have measured the cross section of the 232Th(n, f) reaction at 5.0 MeV. The fission events have been well distinguished from the background alpha events. The present cross section is consistent with the evaluation data from different libraries, which indicates that the fission cross section measurement using our TPC is feasible. By reducing the distance between the two fission samples, the large uncertainty of the present result will be reduced in future experiments.

Poster] Exploiting high-resolution ADS-B data for flight operation reconstruction towards environmental impact assessment

The estimation of the detrimental impact of civil air traffic on the near-airport environment is conducted by means of dedicated assessment tools, usually based on best-practice methods. However, their application involves availability of information on the flight operations, and, although the use of flight tracking data is very helpful, their full inclusion into these tools is challenging. In this paper, following the authors’ previous efforts and with the purpose of future implementation into assessment tools, highly time-resolved datasets from the OpenSky Network are used for the identification of daily flight operations. Then, the ground track reconstruction is carried out with a newly developed algorithm, which exploits the high time resolution to generate smooth trajectories using only segments and circular arcs while maintaining high accuracy, as shown in the results. This work lays the foundation for immediate future developments involving the reconstruction of aircraft performance and the estimation of airport noise levels.

Fast b-tagging at the high-level trigger of the ATLAS experiment in LHC Run 3

The ATLAS experiment relies on real-time hadronic jet reconstruction and b-tagging to record fully hadronic events containing b-jets. These algorithms require track reconstruction, which is computationally expensive and could overwhelm the high-level-trigger farm, even at the reduced event rate that passes the ATLAS first stage hardware-based trigger. In LHC Run 3, ATLAS has mitigated these computational demands by introducing a fast neural-network-based b-tagger, which acts as a low-precision filter using input from hadronic jets and tracks. It runs after a hardware trigger and before the remaining high-level-trigger reconstruction. This design relies on the negligible cost of neural-network inference as compared to track reconstruction, and the cost reduction from limiting tracking to specific regions of the detector. In the case of Standard Model HH → bb̅bb̅, a key signature relying on b-jet triggers, the filter lowers the input rate to the remaining high-level trigger by a factor of five at the small cost of reducing the overall signal efficiency by roughly 2%.

A quantum algorithm for track reconstruction in the LHCb vertex detector

High-energy physics is facing increasingly demanding computational challenges in real-time event reconstruction for the near-future high-luminosity era. Using the LHCb vertex detector as a use case, we explore a new algorithm for particle track reconstruction based on the minimisation of an Ising-like Hamiltonian with a linear algebra approach. The use of a classical matrix inversion technique results in tracking performance similar to the current state-of-the-art but with worse scaling complexity in time. To solve this problem, we also present an implementation as a quantum algorithm, using the Harrow-Hassadim-Lloyd (HHL) algorithm: this approach can potentially provide an exponential speedup as a function of the number of input hits over its classical counterpart, in spite of limitations due to the well-known HHL Hamiltonian simulation and readout problems. The findings presented in this paper shed light on the potential of leveraging quantum computing for real-time particle track reconstruction in high-energy physics.

State-aware real-time tracking and remote reconstruction of a Markov source

State-aware real-time tracking and remote reconstruction of a Markov source

Influence of ocean dynamics on Cuvier’s beaked whale (Ziphius cavirostris): Presence and their prey

Cuvier’s beaked whales (Ziphius cavirostris; Zc) dive below 1000 m to forage predominantly on deep-sea squids. The impact of oceanographic conditions on Zc prey and the effects of anthropogenic sounds on Zc foraging remain unclear. Zc prey distribution is patchy and potentially influenced by mesoscale oceanographic features interacting with local bathymetry. Favorable environmental conditions lead to aggregations of lower trophic level species that attract squid, and potentially increase Zc presence. We collected simultaneous active and passive acoustic data in Tanner Basin, a southern California submarine canyon, intermittently between 2017 and 2022. Passive acoustic data revealed Zc were present throughout all years, with lower presence during late summer and fall. Subsurface Zc 3D track reconstructions indicated a preference for one side of the canyon, where Zc foraged within a layer of potential prey, detected from active acoustic data. Prey concentrations, quantified as volume backscatter strength below ∼1150 m depth, exhibited an increase following the passage of mesoscale features, which were measured using Finite-size Lyapunov Exponents (FSLE). These prey increases drove immediate increases in Zc presence. Understanding potential physical drivers of Zc predator-prey dynamics is a critical first step for assessing natural variability and potential impacts of sonar use on Zc foraging behavior.

Multimodal video and IMU kinematic dataset on daily life activities using affordable devices

Human activity recognition and clinical biomechanics are challenging problems in physical telerehabilitation medicine. However, most publicly available datasets on human body movements cannot be used to study both problems in an out-of-the-lab movement acquisition setting. The objective of the VIDIMU dataset is to pave the way towards affordable patient gross motor tracking solutions for daily life activities recognition and kinematic analysis. The dataset includes 13 activities registered using a commodity camera and five inertial sensors. The video recordings were acquired in 54 subjects, of which 16 also had simultaneous recordings of inertial sensors. The novelty of dataset lies in: (i) the clinical relevance of the chosen movements, (ii) the combined utilization of affordable video and custom sensors, and (iii) the implementation of state-of-the-art tools for multimodal data processing of 3D body pose tracking and motion reconstruction in a musculoskeletal model from inertial data. The validation confirms that a minimally disturbing acquisition protocol, performed according to real-life conditions can provide a comprehensive picture of human joint angles during daily life activities.

HiBrowser: an interactive and dynamic browser for synchronous Hi-C data visualization.

With the development of chromosome conformation capture technology, the genome-wide investigation of higher-order chromatin structure by using high-throughput chromatin conformation capture (Hi-C) technology is emerging as an important component for understanding the mechanism of gene regulation. Considering genetic and epigenetic differences are typically used to explore the pathological reasons on the chromosome and gene level, visualizing multi-omics data and performing an intuitive analysis by using an interactive browser become a powerful and welcomed way. In this paper, we develop an effective sequence and chromatin interaction data display browser called HiBrowser for visualizing and analyzing Hi-C data and their associated genetic and epigenetic annotations. The advantages of HiBrowser are flexible multi-omics navigation, novel multidimensional synchronization comparisons and dynamic interaction system. In particular, HiBrowser first provides an out of the box web service and allows flexible and dynamic reconstruction of custom annotation tracks on demand during running. In order to conveniently and intuitively analyze the similarities and differences among multiple samples, such as visual comparisons of normal and tumor tissue samples, and pan genomes of multiple (consanguineous) species, HiBrowser develops a clone mode to synchronously display the genome coordinate positions or the same regions of multiple samples on the same page of visualization. HiBrowser also supports a pluralistic and precise search on correlation data of distal cis-regulatory elements and navigation to any region on Hi-C heatmap of interest according to the searching results. HiBrowser is a no-build tool, and could be easily deployed in local server. The source code is available at https://github.com/lyotvincent/HiBrowser.

Debugging the FUMILIM minimization package

The suggested package FUMILIM, based on famous FUMILI minimization package, has the following advantages.Unlimited number of parameters (multi-set tasks).Ability to work with multidimensional experimental points, described by a vector function.The preliminary scan is envisaged for complicated tasks.For heavy user's functions the parallel fit is envisaged with the help of OpenMP service.Multi-optional user interface, including the option to ignore wrong experimental points.The package contains popular intrinsic user's functions. All of them can be used without the definition of the parameter initial values.There is a package of fast track reconstruction programs for working with detectors, including drift chambers. The capacity of these programs is about of 106 tracks per second (at 2.8 GHz).In the corrected version a number of bugs is fixed.The service for multi-set tasks has been essentially expanded.Information support of poorly converged tasks and removing of wrong experimental points is expanded.All programs are written in FORTRAN-90. New version program summaryProgram Title: FUMILIM v4CPC Library link to program files:https://doi.org/10.17632/xphc8ctxr3.3Licensing provisions: GPLv3Programming language: Fortran-90Journal reference of previous version: Comput. Phys. Commun. 251 (2020) 107202Does the new version supersede the previous version?: Yes.Reasons for the new version: To extend the class of solvable tasks, fixing a number of bugs.Summary of revisions:• A number of bugs is fixed.• The service for multi-set tasks has been essentially expanded.• Information support of poorly converged task and removing WP is expanded.• Fast programs are accelerated by ≃15%.• Organization of output options is slightly revised, which provided better comfort for users.• Settings of the package through the redefinition of numbers in common-blocks are replaced by calls to short subroutines. This makes the main program more compact. The old way of setting still works.Nature of problem: To minimize χ2-functional.Solution method: Least square method.

Towards a muon scattering tomography system for both low-Z and high-Z materials

Muon scattering tomography (MST) is a non-destructive technique to image various materials by utilizing cosmic ray muons as probes. A typical MST system with a two-fold track detectors is particularly effective in detecting high-Z materials (e.g. nuclear materials), but difficult to recognize low-Z materials (e.g. explosive materials). In this work, we present a concept of MST system to discriminate both low-Z and high-Z materials by extra measuring momentum of low-energy muons with a Cherenkov detector. A toy Monte Carlo simulation to describe detector responses and multiple scatterings of a muon tracking through materials is developed for statistical tests. Based on momentum-dependent track reconstruction and image reconstruction algorithm, we evaluate separation powers of different materials in the system. The results show that momentum measurement of low-energy muons and accurate track reconstruction can improve separation power of low-Z materials significantly. This may enable the MST system to detect both low-Z and high-Z materials with cosmic ray muons in the whole energy range.

Autonomous Asteroid Characterization Through Nanosatellite Swarming

This paper first defines a class of estimation problem called simultaneous navigation and characterization (SNAC), which is a superset of simultaneous localization and mapping (SLAM). A SNAC framework is then developed for the Autonomous Nanosatellite Swarming (ANS) mission concept to autonomously navigate about and characterize an asteroid including the asteroid gravity field, rotational motion, and 3D shape. The ANS SNAC framework consists of three modules: 1) multi-agent optical landmark tracking and 3D point reconstruction using stereovision, 2) state estimation through a computationally efficient and robust unscented Kalman filter, and 3) reconstruction of an asteroid spherical harmonic shape model by leveraging a priori knowledge of the shape properties of celestial bodies. Despite significant interest in asteroids, there are several limitations to current asteroid rendezvous mission concepts. First, completed missions heavily rely on human oversight and Earth-based resources. Second, proposed solutions to increase autonomy make oversimplifying assumptions about state knowledge and information processing. Third, asteroid mission concepts often opt for high size, weight, power, and cost (SWaP-C) avionics for environmental measurements. Finally, such missions often utilize a single spacecraft, neglecting the benefits of distributed space systems. In contrast, ANS is composed of multiple autonomous nanosatellites equipped with low SWaP-C avionics. The ANS SNAC framework is validated through a numerical simulation of three spacecraft orbiting asteroid 433 Eros. The simulation results demonstrate that the proposed architecture provides autonomous and accurate SNAC in a safe manner without an a priori shape model and using only low SWaP-C avionics.

Performance of the MALTA telescope

MALTA is part of the Depleted Monolithic Active Pixel sensors designed in Tower 180 nm CMOS imaging technology. A custom telescope with six MALTA planes has been developed for test beam campaigns at SPS, CERN, with the ability to host several devices under test. The telescope system has a dedicated custom readout, online monitoring integrated into DAQ with realtime hit map, time distribution and event hit multiplicity. It hosts a dedicated fully configurable trigger system enabling to trigger on coincidence between telescope planes and timing reference from a scintillator. The excellent time resolution performance allows for fast track reconstruction, due to the possibility to retain a low hit multiplicity per event which reduces the combinatorics. This paper reviews the architecture of the system and its performance during the 2021 and 2022 test beam campaign at the SPS North Area.

Implementation of ACTS for STCF track reconstruction

With an electron-positron collider operating at center-of-mass-energy 2–7 GeV and a peak luminosity above 0.5 × 1035 cm-2 s-1, the STCF physics program will provide an unique platform for in-depth studies of hadron structure and non-perturbative strong interaction as well as probing new physics beyond the Standard Model in the τ-Charm sector, succeeding the present Beijing Electron-Positron Collider. To fulfill the physics targets and further maximize the physics potential at STCF, the STCF tracking software should have capability to reconstruct charged particles with high efficiency and excellent momentum resolution, especially for the charged particles with low transverse momentum down to 50 MeV. A Common Tracking Software (ACTS) providing a set of detector-independent tracking algorithms is adopted for reconstructing charged tracks with the information of two sub-detectors, a μRWELL-based inner tracker and a drift chamber, at STCF. This is the first demonstration of ACTS for a drift chamber. The implementation details and performance of track reconstruction are presented.

The deep-water BAIKAL-GVD telescope follow-up analysis of the IceCube neutrino alerts

The main goal of the Baikal-GVD deep-sea neutrino telescope is to detect high-energy neutrinos of astrophysical origin by reconstruction of muon tracks or showers of particles generated in interactions of neutrino with water. Since September 2020, Baikal-GVD has been monitoring IceCube telescope alerts about detection of neutrinos with the energy over 100 TeV. When follow-up analysis is carried out in real time, the delay between an IceCube notification and Baikal-GVD analysis does not exceed three minutes. The fast follow-up is complemented by an offline search for coincidences in time intervals of ±1 and ±12 h with refinement of event’s reconstruction. In the absence of a coincidence or in a case of a single coincidence, the value of expected background is calculated and upper limits on the neutrino flux are set.

The Mu2e Crystal and SiPM Calorimeter: Construction Status

The Mu2e experiment at Fermilab searches for the neutrino-less conversion of a negative muon into an electron, with a distinctive signature of a mono-energetic electron with energy of 104.967 MeV. The calorimeter is made of two disks of pure CsI crystals, each read out by two custom large area UV-extended SiPMs. It plays a fundamental role in providing excellent particle identification capabilities and an online trigger filter while improving the track reconstruction, requiring better than 10% energy and 500 ps timing resolutions for 100 MeV electrons. In this paper, we present the status of construction and the Quality Control (QC) performed on the produced crystals and photosensors, the development of the rad-hard electronics and the most important results of the irradiation tests. Construction of the mechanics is also reported. Status and plans for the calorimeter assembly and its first commissioning are described.

Calibration of a Micromegas-based gaseous time projection chamber using cosmic ray muons

We report the calibration of a gaseous Time Projection Chamber based on Micromegas charge readout modules with cosmic ray muons, utilizing their penetrating power and relatively uniform energy deposition per unit length. Muon events were selected through track reconstruction to characterize detector performances, such as the drift velocity, electron lifetime, detector gain, and electric field distortion. The evolution of detector performances over a 50-day data-taking cycle was measured with the muon calibration method. For instance, the drift velocity degraded from 3.40 ± 0.07 cm/μs to 3.06 ± 0.06 cm/μs without gas purification, and then recovered with gas purification. A 137Cs calibration source was also placed inside the detector as a reference for muon calibrations.