scholarly journals Longwall Retreat and Creep Measurement Based on UWB Radar Imaging Method

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Shijia Wang ◽  
Shibo Wang ◽  
Wanli Liu
Keyword(s):  
Measurement Errors ◽  
Signal Propagation ◽  
Radar Imaging ◽  
Imaging Method ◽  
Uwb Radar ◽  
Imaging Results ◽  
Coal Wall ◽  
Safety Production ◽  
Simulation And Experiment ◽  
Creep Measurement

The measurement of longwall retreat and creep displacements is of great significance for the safety production of a coal mine. In order to reliably and accurately obtain the longwall retreat and creep displacements, this paper proposes an ultrawideband (UWB) radar imaging method. The bolt plates fixed in the roadway coal wall are imaged as the target points. First, a signal model is built, and a modified nonlinear chirp scaling (NLCS) imaging algorithm is designed to obtain the high-resolution image. Then, the retreat and creep displacements are estimated based on the imaging results. Finally, simulation and experiment are performed. The simulation results show that the radar imaging method is theoretically feasible to measure the retreat and creep displacements. The measurement errors in the experiment are 0.058 m and 0.040 m, respectively. In the experiment, the radar velocity fluctuation and signal attenuation cause the target azimuth and range errors in the imaging results, which makes the measurement errors in the experiment larger than that in the simulation. This method requires no additional roadway information except for the bolt plates fixed in the coal wall. In addition, the signal propagation of UWB radar is rarely affected by the dust and moisture in the harsh environment.

Accurate Imaging Method for Moving Target with Arbitrary Shape for Multi-Static UWB Radar

2013 ◽  
Vol E96.B (7) ◽  
pp. 2014-2023 ◽  
Author(s):  
Ryo YAMAGUCHI ◽  
Shouhei KIDERA ◽  
Tetsuo KIRIMOTO
Keyword(s):  
Arbitrary Shape ◽  
Imaging Method ◽  
Moving Target ◽  
Uwb Radar ◽  
Accurate Imaging

scholarly journals Analysis and Mapping of Detailed Inner Information of Crystalline Grain by Wavelength-Resolved Neutron Transmission Imaging with Individual Bragg-Dip Profile-Fitting Analysis

2021 ◽  
Vol 11 (11) ◽  
pp. 5219
Author(s):  
Yosuke Sakurai ◽  
Hirotaka Sato ◽  
Nozomu Adachi ◽  
Satoshi Morooka ◽  
Yoshikazu Todaka ◽  
...  
Keyword(s):  
Crystal Orientation ◽  
Perfect Crystal ◽  
Imaging Method ◽  
Transmission Imaging ◽  
Profile Fitting ◽  
Imaging Results ◽  
Integrated Intensity ◽  
Small Change ◽  
Integrated Intensities ◽  
Pulsed Neutron

As a new method for evaluating single crystals and oligocrystals, pulsed neutron Bragg-dip transmission analysis/imaging method is being developed. In this study, a single Bragg-dip profile-fitting analysis method was newly developed, and applied for analyzing detailed inner information in a crystalline grain position-dependently. In the method, the spectrum profile of a single Bragg-dip is analyzed at each position over a grain. As a result, it is expected that changes in crystal orientation, mosaic spread angle and thickness of a perfect crystal can be evaluated from the wavelength, the width and the integrated intensity of the Bragg-dip, respectively. For confirming this effectiveness, the method was applied to experimental data of position-dependent Bragg-dip transmission spectra of a Si-steel plate consisting of oligocrystals. As a result, inner information of multiple crystalline grains could be visualized and evaluated. The small change in crystal orientation in a grain, about 0.4°, could be observed by imaging the Bragg-dip wavelengths. By imaging the Bragg-dip widths, both another grain and mosaic block in a grain were detected. Furthermore, imaging results of the integrated intensities of Bragg-dips were consistent with the results of Bragg-dip width imaging. These small crystallographic changes have not been observed and visualized by previous Bragg-dip analysis methods.

Preoperative identification of the facial nerve in patients with large cerebellopontine angle tumors using high-density diffusion tensor imaging

2012 ◽  
Vol 116 (4) ◽  
pp. 697-702 ◽  
Author(s):  
Neil Roundy ◽  
Johnny B. Delashaw ◽  
Justin S. Cetas
Keyword(s):  
Diffusion Tensor Imaging ◽  
Facial Nerve ◽  
Cerebellopontine Angle ◽  
Diffusion Tensor ◽  
Tumor Resection ◽  
High Density ◽  
Imaging Method ◽  
Study Objective ◽  
Nerve Preservation ◽  
Imaging Results

Object Facial nerve paresis can be a devastating complication following resection of large (> 2.5 cm) cerebellopontine angle (CPA) tumors. The authors have developed and used a new high-density diffusion tensor imaging (HD-DT imaging) method, aimed at preoperatively identifying the location and course of the facial nerve in relation to large CPA tumors. Their study objective was to preoperatively identify the facial nerve in patients with large CPA tumors and compare their HD-DT imaging method with a traditional standard DT imaging method and correlate with intraoperative findings. Methods The authors prospectively studied 5 patients with large (> 2.5 cm) CPA tumors. All patients underwent preoperative traditional standard- and HD-DT imaging. Imaging results were correlated with intraoperative findings. Results Utilizing their HD-DT imaging method, the authors positively identified the location and course of the facial nerve in all patients. In contrast, using a standard DT imaging method, the authors were unable to identify the facial nerve in 4 of the 5 patients. Conclusions The HD-DT imaging method that the authors describe and use has proven to be a powerful, accurate, and rapid method for preoperatively identifying the facial nerve in relation to large CPA tumors. Routine integration of HD-DT imaging in preoperative planning for CPA tumor resection could lead to improved facial nerve preservation.

Ultrawideband (UWB) Radar Imaging of Building Interior: Measurements and Predictions

2009 ◽  
Vol 47 (5) ◽  
pp. 1409-1420 ◽  
Author(s):  
Calvin Le ◽  
Traian Dogaru ◽  
Lam Nguyen ◽  
Marc A. Ressler
Keyword(s):  
Radar Imaging ◽  
Uwb Radar

scholarly journals Phaseless Imaging by Reverse Time Migration: Acoustic Waves

2017 ◽  
Vol 10 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Zhiming Chen ◽  
Guanghui Huang
Keyword(s):  
Acoustic Waves ◽  
Numerical Experiments ◽  
Cross Correlation ◽  
Scattering Data ◽  
Imaging Method ◽  
Total Field ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Time Migration ◽  
Imaging Results

AbstractWe propose a reliable direct imaging method based on the reverse time migration for finding extended obstacles with phaseless total field data. We prove that the imaging resolution of the method is essentially the same as the imaging results using the scattering data with full phase information when the measurement is far away from the obstacle. The imaginary part of the cross-correlation imaging functional always peaks on the boundary of the obstacle. Numerical experiments are included to illustrate the powerful imaging quality

scholarly journals A 3-D SAR Imaging Method Based on Back Projection Algorithm

2021 ◽  
Vol 2083 (3) ◽  
pp. 032050
Author(s):  
Qian Han ◽  
Pengbo Wang ◽  
Xinkai Zhou ◽  
Xinchang Hu ◽  
Yanan Guo
Keyword(s):  
3D Imaging ◽  
Bp Algorithm ◽  
Projection Algorithm ◽  
Imaging Method ◽  
Back Projection ◽  
Imaging Processing ◽  
Imaging Algorithm ◽  
Imaging Results ◽  
2D Imaging ◽  
Low Efficiency

Abstract 3D back projection (BP) algorithm is an imaging algorithm based on time domain echo data, which effectively solves the overlapping mask problem existing in 2D SAR. It can complete the imaging processing of echo signal under any geometry configuration, and has the advantages of high target focusing accuracy and high phase preservation. However, the high complexity and low efficiency of 3D BP imaging algorithm limit its application and development. In this paper, a 3d imaging method based on improved back projection algorithm is proposed. Aiming at the problem that existing imaging algorithms need 2D imaging first and then 3D imaging, an improved 3D BP algorithm is proposed to directly 3D imaging, which avoids 2d imaging processing. The proposed method simplifies the steps of the traditional 3D BP algorithm and improves the efficiency of the algorithm. The validity and effectiveness of the proposed method are verified by the 3d imaging results of simulated lattice targets.

Laser Monitors for High Speed Imaging of Plasma, Beam and Discharge Processes

2016 ◽  
Vol 712 ◽  
pp. 303-307 ◽  
Author(s):  
Maxim V. Trigub ◽  
Stanislav N. Torgaev ◽  
Gennadiy S. Evtushenko ◽  
Vitaliy V. Drobchik
Keyword(s):  
High Speed ◽  
Metal Vapor ◽  
Optical Systems ◽  
Imaging Method ◽  
High Speed Imaging ◽  
Destructive Testing ◽  
Copper Bromide ◽  
Imaging Results ◽  
High Pulse ◽  
Non Destructive

The imaging results of different processes blocked from the observation by the intense background light are presented in this paper. Active optical systems based on high-frequency brightness amplifier are used to decrease the negative factor of the glare. The experimental and modeling results on obtaining high pulse repetition frequencies (PRF) (more than 100 kHz) of copper bromide vapor brightness amplifiers operating in a low input energy mode are shown. The use of metal vapor brightness amplifiers for visual non-destructive testing of fast processes obscured by the glare is also discussed. It has been shown that the imaging method proposed in this paper proves to be the most reliable to obtain the information about objects or processes in a real time mode using high PRF CuBr active media.

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