scholarly journals Deformation Detection Method of Mine Tunnel Based on Mobile Detection System

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5400
Author(s):  
Jian Sun ◽  
Haili Sun ◽  
Ruofei Zhong ◽  
Yulong Han
Keyword(s):  
High Precision ◽  
High Efficiency ◽  
Detection System ◽  
Repeated Measurements ◽  
Structural Safety ◽  
Measurement Unit ◽  
Scanning System ◽  
Control Points ◽  
System Calibration ◽  
Tunnel Section

Subway structure safety detection is an important method to ensure the safe operation of trains. Efficient, high-precision, and automatic tunnel clearance detection is the key to ensure safe operations. This study introduces a mobile tunnel scanning system that integrates a scanner, an inertial measurement unit (IMU), and a rail car. Global Navigation Satellite System (GNSS) time and system hardware calibration are used to synchronize time and space information of the system; the attitude and speed are corrected using the control points from the tunnel to improve the accuracy of absolute positioning. The section coordinate system is converted using the control points and system calibration parameters to complete the tunnel clearance inspection, and the distance between the nearest point of the section and the clear height of the vault is given. Taking Fengxi Road’s Bashan tunnel section of Chongqing Metro Line 5 as an example, the overall system accuracy was tested. The accuracy of chord line measurements was within 1 mm, the internal coincidence accuracy of repeated measurements of the vault clear height was 1.1 mm, the internal coincidence accuracy of repeated measurements of the closest gauge point was 4.8 mm, and the system calibration accuracy was approximately 2 mm. Compared with the existing scheme, the system combines absolute measurement and relative measurement mode to judge the structural safety of tunnel section from multiple angles, high precision, and high efficiency.

scholarly journals A High-Precision Registration Technology Based on Bundle Adjustment in Structured Light Scanning System

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Jianying Yuan ◽  
Qiong Wang ◽  
Xiaoliang Jiang ◽  
Bailin Li
Keyword(s):  
High Precision ◽  
Large Scale ◽  
Structured Light ◽  
Bundle Adjustment ◽  
Scanning System ◽  
Control Points ◽  
Registration Method ◽  
Global Control ◽  
3D Data ◽  
Structured Light Scanning

The multiview 3D data registration precision will decrease with the increasing number of registrations when measuring a large scale object using structured light scanning. In this paper, we propose a high-precision registration method based on multiple view geometry theory in order to solve this problem. First, a multiview network is constructed during the scanning process. The bundle adjustment method from digital close range photogrammetry is used to optimize the multiview network to obtain high-precision global control points. After that, the 3D data under each local coordinate of each scan are registered with the global control points. The method overcomes the error accumulation in the traditional registration process and reduces the time consumption of the following 3D data global optimization. The multiview 3D scan registration precision and efficiency are increased. Experiments verify the effectiveness of the proposed algorithm.

Research and Monitoring of Metro Tunnel Deformation Based on Internet of Things

2014 ◽  
Vol 484-485 ◽  
pp. 507-510
Author(s):  
Xiao Wei Du ◽  
Yong Tao Gao
Keyword(s):  
Detection System ◽  
Structural Safety ◽  
Subway Tunnel ◽  
Wireless Data ◽  
Tunnel Wall ◽  
Cross Sectional ◽  
Safety Testing ◽  
Wireless Data Transmission ◽  
Tunnel Section ◽  
Tunnel Cross Section

After a long subway tunnel operators will produce cross-sectional deformation. Articles designed vehicle laser ranging device for continuous measurement of tunnel wall to test their deformed state. The paper also describes the tunnel cross-section deformation measurement method, contour fitting principles and error analysis and networking technology for wireless data transmission methods. The detection system is designed to achieve a tunnel section of the structural safety testing and deformation that may occur timely disaster warning, the safe operation of the subway tunnel to provide effective protection.

scholarly journals Design and Evaluation of a Permanently Installed Plane-Based Calibration Field for Mobile Laser Scanning Systems

2020 ◽  
Vol 12 (3) ◽  
pp. 555 ◽  
Author(s):  
Erik Heinz ◽  
Christoph Holst ◽  
Heiner Kuhlmann ◽  
Lasse Klingbeil
Keyword(s):  
Reference Point ◽  
Laser Scanning ◽  
Point Clouds ◽  
Measurement Unit ◽  
Scanning System ◽  
Control Points ◽  
Lever Arm ◽  
Laser Scanning System ◽  
The Impact ◽  
Scanning Systems

Mobile laser scanning has become an established measuring technique that is used for many applications in the fields of mapping, inventory, and monitoring. Due to the increasing operationality of such systems, quality control w.r.t. calibration and evaluation of the systems becomes more and more important and is subject to on-going research. This paper contributes to this topic by using tools from geodetic configuration analysis in order to design and evaluate a plane-based calibration field for determining the lever arm and boresight angles of a 2D laser scanner w.r.t. a GNSS/IMU unit (Global Navigation Satellite System, Inertial Measurement Unit). In this regard, the impact of random, systematic, and gross observation errors on the calibration is analyzed leading to a plane setup that provides accurate and controlled calibration parameters. The designed plane setup is realized in the form of a permanently installed calibration field. The applicability of the calibration field is tested with a real mobile laser scanning system by frequently repeating the calibration. Empirical standard deviations of <1 ... 1.5 mm for the lever arm and <0.005 ∘ for the boresight angles are obtained, which was priorly defined to be the goal of the calibration. In order to independently evaluate the mobile laser scanning system after calibration, an evaluation environment is realized consisting of a network of control points as well as TLS (Terrestrial Laser Scanning) reference point clouds. Based on the control points, both the horizontal and vertical accuracy of the system is found to be < 10 mm (root mean square error). This is confirmed by comparisons to the TLS reference point clouds indicating a well calibrated system. Both the calibration field and the evaluation environment are permanently installed and can be used for arbitrary mobile laser scanning systems.

scholarly journals Absolute Positioning and Orientation of MLSS in a Subway Tunnel Based on Sparse Point-Assisted DR

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 645
Author(s):  
Qian Wang ◽  
Chao Tang ◽  
Cuijun Dong ◽  
Qingzhou Mao ◽  
Fei Tang ◽  
...  
Keyword(s):  
Coordinate System ◽  
Laser Scanning ◽  
Local Coordinate System ◽  
Point Clouds ◽  
Measurement Unit ◽  
Scanning System ◽  
Control Points ◽  
Starting Point ◽  
Inspection Work ◽  
Subway Tunnels

When performing the inspection of subway tunnels, there is an immense amount of data to be collected and the time available for inspection is short; however, the requirement for inspection accuracy is high. In this study, a mobile laser scanning system (MLSS) was used for the inspection of subway tunnels, and the key technology of the positioning and orientation system (POS) was investigated. We utilized the inertial measurement unit (IMU) and the odometer as the core sensors of the POS. The initial attitude of the MLSS was obtained by using a static initial alignment method. Considering that there is no global navigation satellite system (GNSS) signal in a subway, the forward and backward dead reckoning (DR) algorithm was used to calculate the positions and attitudes of the MLSS from any starting point in two directions. While the MLSS passed by the control points distributed on both sides of the track, the local coordinates of the control points were transmitted to the center of the MLSS by using the ranging information of the laser scanner. Then, a four-parameter transformation method was used to correct the error of the POS and transform the 3-D state information of the MLSS from a navigation coordinate system (NCS) to a local coordinate system (LCS). This method can completely eliminate a MLSS’s dependence on GNSS signals, and the obtained positioning and attitude information can be used for point cloud data fusion to directly obtain the coordinates in the LCS. In a tunnel of the Beijing–Zhangjiakou high-speed railway, when the distance interval of the control points used for correction was 120 m, the accuracy of the 3-D coordinates of the point clouds was 8 mm, and the experiment also showed that it takes less than 4 h to complete all the inspection work for a 5–6 km long tunnel. Further, the results from the inspection work of Wuhan subway lines showed that when the distance intervals of the control points used for correction were 60 m, 120 m, 240 m, and 480 m, the accuracies of the 3-D coordinates of the point clouds in the local coordinate system were 4 mm, 6 mm, 7 mm, and 8 mm, respectively.

Detection System for Scratch on the Wheel Tread of Train Based on PSD

2012 ◽  
Vol 249-250 ◽  
pp. 9-14
Author(s):  
Ping He ◽  
Ying Li ◽  
Yuan Guo ◽  
Pan Li
Keyword(s):  
Human Computer Interaction ◽  
High Precision ◽  
High Speed ◽  
High Efficiency ◽  
Detection System ◽  
High Reliability ◽  
Computing System ◽  
Machine Interface ◽  
Moving Train ◽  
Scratch Detection

At present, scratch on the wheel tread of train is detected mostly in low-speed circumstance in China. For this reason, a high-precision detection system for scratch on the wheel tread of train based on PSD which adapts to high-speed moving train is presented. Firstly, the principle of scratch detection based on PSD is given. Then, the acquisition and computing system for scratch on the wheel tread of train based on PSD is designed with TMS320F2812. Finally, the human-computer interaction system based on Visual Studio 6.0 is designed. The results show that the detection system for scratch on the wheel tread of train based on PSD can realize detection for scratch on the wheel tread of train and have advantages of high precision, high efficiency, high reliability and well human-machine interface.

scholarly journals Adaptive Detection of Direct-Sequence Spread-Spectrum Signals Based on Knowledge-Enhanced Compressive Measurements and Artificial Neural Networks

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2538
Author(s):  
Shuang Zhang ◽  
Feng Liu ◽  
Yuang Huang ◽  
Xuedong Meng
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Spread Spectrum ◽  
High Efficiency ◽  
Detection System ◽  
Direct Sequence Spread Spectrum ◽  
Detection Performance ◽  
Detection Methods ◽  
Direct Sequence ◽  
Artificial Neural

The direct-sequence spread-spectrum (DSSS) technique has been widely used in wireless secure communications. In this technique, the baseband signal is spread over a wider bandwidth using pseudo-random sequences to avoid interference or interception. In this paper, the authors propose methods to adaptively detect the DSSS signals based on knowledge-enhanced compressive measurements and artificial neural networks. Compared with the conventional non-compressive detection system, the compressive detection framework can achieve a reasonable balance between detection performance and sampling hardware cost. In contrast to the existing compressive sampling techniques, the proposed methods are shown to enable adaptive measurement kernel design with high efficiency. Through the theoretical analysis and the simulation results, the proposed adaptive compressive detection methods are also demonstrated to provide significantly enhanced detection performance efficiently, compared to their counterpart with the conventional random measurement kernels.

HENDES-high efficiency neutron detection system for correlation measurements with HI beams

1997 ◽  
Author(s):  
W. H. Trzaska ◽  
V. A. Rubchenya ◽  
A. A. Alexandrov ◽  
I. D. Alkhazov ◽  
J. Äystö ◽  
...  
Keyword(s):  
High Efficiency ◽  
Detection System ◽  
Neutron Detection
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