Research on large-scale plane coordinate measurement technology based on multi-axis synchronous laser interferometry

2021 ◽  
Author(s):  
Wang Shuhui ◽  
Sun Shuanghua ◽  
Kang Yanhui ◽  
Zhang Fumin ◽  
Wang Heyan ◽  
...  
Keyword(s):  
Large Scale ◽  
Laser Interferometry ◽  
Measurement Technology ◽  
Coordinate Measurement

scholarly journals Bringing optical metrology to testing and inspection activities in civil engineering

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 108
Author(s):  
Luis Martins ◽  
Álvaro Ribeiro ◽  
Maria Do Céu Almeida ◽  
João Alves e Sousa
Keyword(s):  
Large Scale ◽  
Civil Engineering ◽  
National Laboratory ◽  
Research Work ◽  
Construction Materials ◽  
Laser Interferometry ◽  
Suspension Bridge ◽  
Shaking Table ◽  
Optical Metrology ◽  
Future Research

<p class="Abstract">Optical metrology has an increasing impact on observation and experimental activities in Civil Engineering, contributing to the Research and development of innovative, non-invasive techniques applied in testing and inspection of infrastructures and construction materials to ensure safety and quality of life. Advances in specific applications are presented in the paper, highlighting the application cases carried out by LNEC (the Portuguese National Laboratory for Civil Engineering). </p><p class="Abstract">The examples include: (i) structural monitoring of a long-span suspension bridge; (ii) use of close circuit television (CCTV) cameras in drain and sewer inspection; (iii) calibration of a large-scale seismic shaking table with laser interferometry; (iv) destructive mechanical testing of masonry specimens.</p><p class="Abstract">Current and future research work in this field is emphasized in the final section. Examples given are related to the use of Moiré techniques for digital modelling of reduced-scale hydraulic surfaces and to the use of laser interferometry for calibration of strain measurement standard for the geometrical evaluation of concrete testing machines.</p>

scholarly journals UAV and terrestrial laser scanner data processing for large scale topographic mapping

2020 ◽  
Vol 50 ◽  
pp. 63-73
Author(s):  
Ganbold Ulziisaikhan ◽  
Dash Oyuntsetseg
Keyword(s):  
Data Processing ◽  
Spatial Data ◽  
Large Scale ◽  
Laser Scanner ◽  
Measurement Technology ◽  
Topographic Mapping ◽  
Terrestrial Laser Scanner ◽  
Scanner Data ◽  
Processing Scheme ◽  
Digital Elevation

Integrating spatial data from different sources results in visualization, which is the last step in the process of digital basic topographic map creation. Digital elevation model and visualization will used for geomorphological mapping, geospatial database, urban planning and etc. Large scale topographic mapping in the world countries is really a prominent challenge in geospatial industries today. The purpose of this work is to integrate laser scanner data with the ones generated by aerial photogrammetry from UAV, to produce detailed maps that can used by geodetic engineers to optimize their analysis. In addition, terrestrial - based LiDAR scans and UAV photogrammetric data were collected in Sharga hill in the north zone of Mongolia. In this paper, different measurement technology and processing software systems combined for topographic mapping in the data processing scheme. UTM (Universal Transverse Mercator) projected coordinate system calculated in WGS84 reference ellipsoid. Feature compilation involving terrestrial laser scanner data and UAV data will integrated to offer Digital Elevation Models (DEM) as the main interest of the topographic mapping activity. Used UAV generate high-resolution orthomosaics and detailed 3D models of areas where no data, are available. That result issued to create topographic maps with a scale of 1:1000 of geodetic measurements. Preliminary results indicate that discontinuity data collection from UAV closely matches the data collected using laser scanner.

scholarly journals CENTIMETRE-ACCURACY IN FORESTS AND URBAN CANYONS – COMBINING A HIGH-PERFORMANCE IMAGE-BASED MOBILE MAPPING BACKPACK WITH NEW GEOREFERENCING METHODS

2020 ◽  
Vol V-1-2020 ◽  
pp. 333-341
Author(s):  
S. Blaser ◽  
J. Meyer ◽  
S. Nebiker ◽  
L. Fricker ◽  
D. Weber
Keyword(s):  
Web Services ◽  
High Performance ◽  
Large Scale ◽  
Superior Performance ◽  
City Centre ◽  
Visual Localization ◽  
Mobile Mapping ◽  
Coordinate Measurement ◽  
Collaborative Processes ◽  
Mobile Mapping System

Abstract. Advances in digitalization technologies lead to rapid and massive changes in infrastructure management. New collaborative processes and workflows require detailed, accurate and up-to-date 3D geodata. Image-based web services with 3D measurement functionality, for example, transfer dangerous and costly inspection and measurement tasks from the field to the office workplace. In this contribution, we introduced an image-based backpack mobile mapping system and new georeferencing methods for capture previously inaccessible outdoor locations. We carried out large-scale performance investigations at two different test sites located in a city centre and in a forest area. We compared the performance of direct, SLAM-based and image-based georeferencing under demanding real-world conditions. Both test sites include areas with restricted GNSS reception, poor illumination, and uniform or ambiguous geometry, which create major challenges for reliable and accurate georeferencing. In our comparison of georeferencing methods, image-based georeferencing improved the median precision of coordinate measurement over direct georeferencing by a factor of 10–15 to 3 mm. Image-based georeferencing also showed a superior performance in terms of absolute accuracies with results in the range from 4.3 cm to 13.2 cm. Our investigations showed a great potential for complementing 3D image-based geospatial web-services of cities as well as for creating such web services for forest applications. In addition, such accurately georeferenced 3D imagery has an enormous potential for future visual localization and augmented reality applications.

Non-destructive testing of aerospace composite materials using digital shearography

1998 ◽  
Vol 212 (1) ◽  
pp. 21-30 ◽  
Author(s):  
W Steinchen ◽  
L Yang ◽  
G Kupfer ◽  
P Mäckel
Keyword(s):  
Large Scale ◽  
Laser Interferometry ◽  
Honeycomb Structure ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Measuring Device ◽  
Large Scale Structures ◽  
Reinforced Plastics ◽  
Digital Imaging Processing ◽  
Non Destructive

Digital shearography, a laser interferometry technique in conjunction with the digital imaging processing, has the potential for identifying defects both in small- and large-scale structures. This paper will focus on the recent development of digital shearography for non-destructive testing (NDT). With the improvement of the measuring methods and the development of a small and mobile measuring device in conjunction with a user-guided program, Shearwin, this laser inspection technique can be used easily in the environment of fieldwork. A few examples show its application in the aerospace industry for NDT of composites, e.g. GLARE panel, honeycomb structure and glass (or carbon)-fibre-reinforced plastics, etc.

Distributed Optical Sensor Network with Self-Monitoring Mechanism for Accurate Indoor Location and Coordinate Measurement

2012 ◽  
Vol 190-191 ◽  
pp. 972-976 ◽  
Author(s):  
Ling Hui Yang ◽  
Yi Wang ◽  
Ji Gui Zhu ◽  
Xue You Yang
Keyword(s):  
Sensor Network ◽  
Large Scale ◽  
Geometric Model ◽  
Optical Receivers ◽  
Self Monitoring ◽  
Indoor Location ◽  
Coordinate Measurement ◽  
Location Service ◽  
Distributed Framework ◽  
Monitoring Mechanism

In order to provide accurate and robust indoor location service for large-scale mechanical manufacturing, a sensor network consisting of laser transmitters and optical receivers is proposed in a distributed framework. Geometric model described by rotating plane equations is established, re-ceiver’s location algorithm is achieved by utilizing intersection constraint of multiple laser planes form different transmitters. A self-monitoring mechanism for sensor network is also presented by introducing redundant fixed receivers as reference. Experiment has shown that the measuring accu-racy of a minimal sensor network is better than 0.2mm and self-monitoring mechanism can effectively guarantee the accuracy of the measurement results.

scholarly journals A Real-Time Measurement Method of Air Refractive Index Based on Special Material Etalon

2018 ◽  
Vol 8 (11) ◽  
pp. 2325 ◽  
Author(s):  
Guo-Ying Ren ◽  
Xing-Hua Qu ◽  
Shuang Ding
Keyword(s):  
Refractive Index ◽  
Real Time ◽  
Direct Measurement ◽  
Measurement Method ◽  
Measurement Accuracy ◽  
Laser Interferometry ◽  
Measurement Technology ◽  
Measurement Principle ◽  
Environmental Responses ◽  
Realization Process

In the precise displacement measurement based on laser interferometry, the measurement technology for the refractive index of air is widely used to improve the measurement accuracy. However, the existing measurement method of the refractive index of air based on direct measurement is not easy to realize in practical work because of its complex measurement principle and the huge volume of the measurement device; while the measurement accuracy and speed based on the indirect method cannot adapt to the real-time, fast and accurate measurement requirements of industrially changing environments, resulting in distortion of the results. In this study, a measurement method of the refractive index of air based on a special material etalon is proposed. The method enables rapid and direct measurement of the air refractive index when the environment changes and it is given the realization process. Finally, the experimental results show that the deviation between this method and the modified Edlen formula is about 2.5 × 10−7, and that this method can quickly reflect the changes of the environment, which prove the correctness of this method and its ability manage rapid environmental responses. This method is worth popularizing in industrial measurement.

Relationship between Coordinate Transformation Uncertainty and Arrangement of Common Reference Points in Large-Scale Metrology

2017 ◽  
Vol 870 ◽  
pp. 309-314
Author(s):  
Jia Rui Lin ◽  
Yu Ren ◽  
Yin Guo ◽  
Yong Jie Ren ◽  
Ling Hui Yang ◽  
...  
Keyword(s):  
Coordinate Transformation ◽  
Large Scale ◽  
Transformation Process ◽  
Reference Points ◽  
Estimation Model ◽  
Individual Measurement ◽  
Coordinate Measurement ◽  
Measurement Systems ◽  
Common Reference ◽  
The Relationship

Large-scale coordinate measurement frequently involves unifying coordinate frames of individual measurement systems by aligning two sets of common reference points, which is called coordinate transformation. During this transformation process, some uncertainty is introduced into the final measurement results from common points. This paper studies the relationship between this introduced uncertainty and common points in order to minimize it. First, an uncertainty estimation model of coordinate transformation is developed to quantify the introduced uncertainty. Then the relationship between the introduced uncertainty and the arrangement of the common points is simulationally and experimentally investigated and some feasible and efficient arrangements are proposed in view of minimizing it.

scholarly journals Automatic Guidance Method for Laser Tracker Based on Rotary-Laser Scanning Angle Measurement

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4168
Author(s):  
Linghui Yang ◽  
Yuanlin Pan ◽  
Jiarui Lin ◽  
Yang Liu ◽  
Yue Shang ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Large Scale ◽  
Critical Role ◽  
Angle Measurement ◽  
Measurement Technology ◽  
Laser Tracker ◽  
Scanning Angle ◽  
Laser Tracking ◽  
Automatic Guidance ◽  
Laser Trackers

Laser-tracking measurement systems (laser tracker) have been playing a critical role in large-scale 3D high-precision coordinate measurement. However, the existing visual guidance of laser trackers is still limited by the disadvantages of operator-dependence, small-angle view field, time-consuming laser-guided process. This paper presents an automatic guidance method for laser trackers based on the rotary-laser scanning angle measurement technology. In this method, a special target consisting of six photoelectric receivers and a retroreflector is integrated into the rotary-laser scanning transmitter’ coordinate systems. Real-time constraints calculated by the proposed method would provide the coordinates of the target in a laser tracker coordinates system for guidance. Finally, the experimental results verified the automatic re-establish of sightline can be realized in horizontal 360° angle field within tens of arc-seconds, and this method is robust against the fast movement of the target.

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