- 标题
- 摘要
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- 实验方案
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Development of Monitoring Method of Respiratory Waveform in Thoracicoabdominal Part Using Web Camera; ウェブカメラを用いた胸腹部呼吸波形のモニタリング法の開発;
摘要： Countermeasures against respiratory movement are important for tumors of thorax and abdomen in stereotactic body radiation therapy. In the present paper, a web-camera-based-respiratory monitoring method without contact with patient's body was proposed for respiratory study. Thoracic and abdominal motion images were taken by a web camera, and were analyzed using simple image-processing techniques for obtaining respiratory waveforms. Four motion images with different respiration rate were obtained from resuscianne simulator. Respiration waveforms were estimated from the moving images by the proposed method, and were compared with respiration waveforms obtained by the conventional respiratory monitoring device. That was found to have a strong correlation. In addition, the two waveforms were similar in Bland–Altman method comparison. The proposed method can provide non-contact, non-invasive, simple, and realistic respiratory monitoring system for radiotherapy.
关键词： motion image analysis,resuscianne simulator,respiratory movement,radiation therapy,breath waveform
更新于2025-09-23 15:23:52
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Performance Assessment of High Resolution Airborne Full Waveform LiDAR for Shallow River Bathymetry
摘要： We evaluate the performance of full waveform LiDAR decomposition algorithms with a high-resolution single band airborne LiDAR bathymetry system in shallow rivers. A continuous wavelet transformation (CWT) is proposed and applied in two fluvial environments, and the results are compared to existing echo retrieval methods. LiDAR water depths are also compared to independent field measurements. In both clear and turbid water, the CWT algorithm outperforms the other methods if only green LiDAR observations are available. However, both the definition of the water surface, and the turbidity of the water significantly influence the performance of the LiDAR bathymetry observations. The results suggest that there is no single best full waveform processing algorithm for all bathymetric situations. Overall, the optimal processing strategies resulted in a determination of water depths with a 6 cm mean at 14 cm standard deviation for clear water, and a 16 cm mean and 27 cm standard deviation in more turbid water.
关键词： bathymetry,full waveform,wavelet transformation,LiDAR
更新于2025-09-23 15:23:52
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[IEEE 2018 17th International Conference on Ground Penetrating Radar (GPR) - Rapperswil, Switzerland (2018.6.18-2018.6.21)] 2018 17th International Conference on Ground Penetrating Radar (GPR) - Theory for 1D full waveform inversion of surface GPR data
摘要： In one dimension, full waveform inversion is shown to be a linear problem under several conditions. I show that if the magnetic permeability can be assumed constant and electric conductivity to be zero, measuring the magnetic ?eld at the surface or in the air suf?ces as input data. I present the theory using integral equations that describe the electric ?eld inside the medium in terms of contrast sources. The electric ?eld inside the medium can be computed from the measured magnetic ?eld by solving a Marchenko equation. Once this ?eld is known only the contrast function is unknown and can be found by matrix inversion. If the electric ?eld is also measured the inverse problem can be solved recursively. In one dimension depth is intrinsically unknown and I use recording time as a replacing coordinate. After the electric permittivity is known as a function of one-way travel time from surface to a depth level inside the medium, the depth level can be found by an integral. This produces electric permittivity as a function of depth and full waveform inversion is complete. A simple numerical example demonstrates the method.
关键词： full waveform inversion,GPR,autofocusing,1D
更新于2025-09-23 15:23:52
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Full waveform inversion based on inequality constraint for cross-hole radar
摘要： Cross-hole radar is an effective method for geophysical exploration of underground geological conditions. Besides cross-hole radar, some geological information can be obtained by other methods, such as preliminary geological survey, geologic drilling and long-distance geophysical prospecting. This information can work as priori information to help interpret cross-hole radar detection data. Full waveform inversion (FWI) is an advanced inversion method for cross-hole radar, having higher resolution than the ray tomography method. However, traditional FWI for cross-hole radar takes less advantage of the prior information. Therefore, the introduction of the priori information into FWI is worthy of in-depth study to improve information and improve the accuracy and stability of FWI. The reasonable value inversion quality. Here we use a special penalty function to impose inequality constraint on the objective function, and then calculate a new update step length value different from the traditional FWI. We use this method to introduce the priori range of weight coefficients is discussed, which can control the strength of inequality constraint. Several inversion examples are designed to validate the effect of this improved FWI method. The inversion examples for synthetic and field data show that FWI based on inequality constraint for cross-hole radar has better inversion effect than the traditional FWI. To a certain extent, the introduction of inequality constraint can constrain inversion process, improve the inversion stability and provide higher precision inversion results.
关键词： Inequality constraint,Inverse theory,Cross-hole radar,Full waveform inversion,Priori information
更新于2025-09-23 15:23:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Gaussian Decomposition of LiDAR Waveform Data Simulated by Dart
摘要： Light Detection And Ranging (LiDAR) techniques have been extensively applied in spaceborne, airborne and ground-based platforms. Understanding LiDAR data requires modeling approaches that can precisely account for the physical interactions between the emitted laser pulse and reflecting targets. Diverse LiDAR data types arise from different systems, platforms, and applications. However, most existing physical models consider only single pulse configurations to simulate large footprint LiDAR waveforms, which do not correspond to standard data formats. Hence, in many cases, model outputs are not well adapted to research conducted with actual LiDAR systems, especially for Aerial and Terrestrial Laser Scanning (ALS and TLS) systems. The Discrete Anisotropic Radiation Transfer (DART) model provides accurate and efficient simulations of multiple LiDAR pulses from all platform types. This paper presents the latest development of the DART LiDAR module: Gaussian decomposition of the simulated ALS and TLS waveforms followed by the provision of LiDAR point cloud and waveforms in text and standard ASPRS LAS formats.
关键词： point cloud,DART,waveform,LiDAR,ALS,Gaussian decomposition,TLS
更新于2025-09-23 15:23:52
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[IEEE 2018 17th International Conference on Ground Penetrating Radar (GPR) - Rapperswil, Switzerland (2018.6.18-2018.6.21)] 2018 17th International Conference on Ground Penetrating Radar (GPR) - Full Waveform Inversion of Cross-hole Radar Data Using Envelope Objective Function
摘要： The full waveform inversion (FWI) has been used as a high resolution imaging method for cross-hole radar inversion implementation, however, when FWI is used to process field data, it encounters a variety of problems and causes the inversion to fall into a local minimum. One problem is that the GPR data lacks low frequency information. An effective way is to provide an accurate initial model for FWI. The fact is that the underground media is unknown which results in difficult to obtain ideal result in FWI. By means of the derivation of the objective function, the gradient formula of the envelope waveform inversion (EWI) is derived by taking the derivation of the EWI misfit function with respect to the model parameter. By comparing the inversion results of the EWI with that of the traditional FWI without low-frequency information in the observed GPR data, we found that the EWI can effectively restore missing low-frequency information and has better inversion ability for low-frequency missing data.
关键词： cross-hole radar,envelope,full waveform inversion,low frequency component,initial model
更新于2025-09-23 15:23:52
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[IEEE 2018 Innovations in Intelligent Systems and Applications (INISTA) - Thessaloniki (2018.7.3-2018.7.5)] 2018 Innovations in Intelligent Systems and Applications (INISTA) - Piezologist: A Novel Wearable Piezoelectric-based Cardiorespiratory Monitoring System
摘要： In this paper, the design, prototyping and software development of a novel wearable cardiorespiratory parameters monitoring sensor and software applications illustrated. Piezologist is an unobtrusive chest worn device. It comprises a patch-type sensor and a mobile application. The sensor utilizes piezoelectric material as the cardiorespiratory signal sensing component and MetaWearC board as the signal acquisition unit. The board also comes with Bluetooth Low Energy (BLE) support which is utilized for the raw signal transmission. The novelty aspect of the system rests on the fact that not only using a single cheap piezoelectric sheet common cardiorespiratory parameters (such as heart rate, respiration rate, and cycles) were obtained similar to previous studies but ECG waveform and blood pressure data were also extracted successfully using the same sensor. In addition, sensor packaging design and prototyping and their effect on the acquired signal strength on one hand and the package size (volume and weight) on the other hand were studied and reported. For performance validation purpose, the developed cardiorespiratory monitoring system results were validated against two commercial sensor devices namely 3-lead ECG sensor from eHealth sensor kit and Zephyr belt-type BioHarness sensor, and the results were reported herein. The validation process outcomes confirmed that the cardiorespiratory signals extracted using Piezologist conform with a heartbeat, respiratory cycle and ECG waveform obtained using the commercial sensors. Furthermore, a usability study was conducted to compare the user experience offered by Piezologist for measuring cardiorespiratory parameters against the commercially available sensors. The study highlighted the potential that Piezologist will take over the commercial available belt-type, watch-type and 3-lead ECG sensors.
关键词： biomedical signal processing,heart rate extraction,wearable sensors,Sensors,Vital signs,ECG waveform,Home healthcare,cardiorespiratory,Heartbeats,mobile healthcare,Respiration rate
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - Sheffield (2018.7.8-2018.7.11)] 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - Restoration of Multilayered Single-Photon 3D Lidar Images
摘要： This paper proposes a new algorithm to restore 3D single-photon Lidar images obtained under challenging realistic scenarios which include imaging multilayered targets such as semi-transparent surfaces or imaging through obscurants such as scattering media (e.g., water, fog). The Data restoration and exploitation is achieved by minimising an appropriate cost-function accounting for the data Poisson statistics and the available prior knowledge regarding the depth and reflectivity estimates. The proposed algorithm takes into account (i) the non-local spatial correlations between pixels, by using a convex non-local total variation (TV) regularizer, and (ii) the clustered nature of the returned photons, by using a collaborative sparse prior. The resulting minimization problem is solved using the alternating direction method of multipliers (ADMM) that offers good convergence properties. The algorithm is validated using both synthetic and real data which show the benefit of the proposed strategy in the sparse regime due to a fast acquisition or in presence of a high background due to obscurants.
关键词： Poisson statistics,collaborative sparsity,ADMM,image restoration,NR3D,Lidar waveform
更新于2025-09-23 15:22:29
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Gas Breakdown and Discharge Formation in High-Power Impulse Magnetron Sputtering
摘要： Discharge behaviors of high-power impulse magnetron sputtering with different targets have been investigated. Distinct current–voltage curves and target current waveforms are observed. Breakdown voltage and the maximum target current show a periodic drop with the increase of atomic number in subgroups and periods. The target current density is found to be mainly affected by the secondary electron emission yield. Thus, its magnitude is unable to directly evaluate the ionization degree of sputtered atoms in high-power impulse magnetron sputtering (HiPIMS) process. In this paper, the interactive influence of secondary electron emission, sputter yield, and ionization energy on the ionization degree of sputtered atoms is discussed based on the analysis of the voltage and current characteristics. As a result, targets can be categorized into three sorts according to the ionization degree: 1) low ionization degree targets, such as Ag and C less than 10%; 2) intermediate ionization degree targets like Cr and Cu with 55% and 35%; 3) Ti, Zr, and Mo targets with the second ionization processes. These results provide institutive operation ranges for the state-of-the-art HiPIMS applications.
关键词： optical emission spectroscopy (OES),ionization degree,Current waveform,gas breakdown,high-power impulse magnetron sputtering (HiPIMS)
更新于2025-09-23 15:22:29
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The investigation of a new fast timing system based on DRS4 waveform sampling system
摘要： In the study of nuclear structure, the fast timing technique can be used to measure the lifetime of excited states. In the paper, we have developed a new fast timing system, which is made up of two LaBr3:Ce detectors and a set of waveform sampling system. The sampling system based on domino ring sampler version 4 chip (DRS4) can digitize and store the waveform information of detector signal, with a smaller volume and higher timing accuracy, and the waveform data are performed by means of digital waveform analysis methods. The coincidence time resolution of the fast timing system for two annihilation 511 keV g photon is 200ps (FWHM), the energy resolution is 3.5%@511 keV, and the energy linear response in the large dynamic range is perfect. Meanwhile, to verify the fast timing performance of the system, the t 152Gd-21 decay of 152Eu source is measured. The measured lifetime is 45.3(±5.0)ps, very close to the value of the National Nuclear Data Center (NNDC: 46.2((±3.9)ps). The experimental results indicate that the fast timing system is capable of measuring the lifetime of dozens of ps. Therefore, the system can be widely used in the research of the fast timing technology.
关键词： Waveform sampling system,Excited state lifetime,LaBr3:Ce scintilator,Fast timing technique
更新于2025-09-23 15:22:29