scholarly journals Shape Deformation Monitoring for VLBI Antenna Using Close-Range Photogrammetry and Total Least Squares

2016 ◽  
Vol 34 (1) ◽  
pp. 99-107
Author(s):  
Hyuk Gil Kim ◽  
Hong Sik Yun
Keyword(s):  
Least Squares ◽  
Total Least Squares ◽  
Deformation Monitoring ◽  
Shape Deformation ◽  
Close Range Photogrammetry ◽  
Close Range

scholarly journals Mapping Forest Structure Using UAS inside Flight Capabilities

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2245 ◽  
Author(s):  
Karel Kuželka ◽  
Peter Surový
Keyword(s):  
Least Squares ◽  
Forest Structure ◽  
European Beech ◽  
Point Clouds ◽  
Unmanned Aerial Systems ◽  
Structure Mapping ◽  
Close Range Photogrammetry ◽  
3D Point Clouds ◽  
Ellipse Method ◽  
Close Range

We evaluated two unmanned aerial systems (UASs), namely the DJI Phantom 4 Pro and DJI Mavic Pro, for 3D forest structure mapping of the forest stand interior with the use of close-range photogrammetry techniques. Assisted flights were performed within two research plots established in mature pure Norway spruce (Picea abies (L.) H. Karst.) and European beech (Fagus sylvatica L.) forest stands. Geotagged images were used to produce georeferenced 3D point clouds representing tree stem surfaces. With a flight height of 8 m above the ground, the stems were precisely modeled up to a height of 10 m, which represents a considerably larger portion of the stem when compared with terrestrial close-range photogrammetry. Accuracy of the point clouds was evaluated by comparing field-measured tree diameters at breast height (DBH) with diameter estimates derived from the point cloud using four different fitting methods, including the bounding circle, convex hull, least squares circle, and least squares ellipse methods. The accuracy of DBH estimation varied with the UAS model and the diameter fitting method utilized. With the Phantom 4 Pro and the least squares ellipse method to estimate diameter, the mean error of diameter estimates was −1.17 cm (−3.14%) and 0.27 cm (0.69%) for spruce and beech stands, respectively.

scholarly journals USING SMART PHONES FOR DEFORMATIONS MEASUREMENTS OF STRUCTURES

2017 ◽  
Vol 43 (2) ◽  
pp. 66-72 ◽  
Author(s):  
Khalid L. A. EL-ASHMAWY
Keyword(s):  
Least Squares ◽  
Smart Phones ◽  
Digital Cameras ◽  
Object Space ◽  
Close Range Photogrammetry ◽  
Variable Displacement ◽  
Close Range ◽  
Displacement Transducers ◽  
Better Than

The present work tests the suitability of using the digital cameras of smart phones for close range photogrammetry applications. For this purpose two cameras of smart phones Lumia 535 and Lumia 950 XL were used. The resolutions of the two cameras are 5 and 20 Mpixels respectively. The tests consist of (a) self calibration of the two cameras, (b) the implementation of close-range photogrammetry using the cameras of the two smart phones, theodolite intersection with LST method, and linear variable displacement transducers (LVDTs) for the measurement of vertical deflections, and (c) accuracy of photogrammetric determination of object space coordinates. The results of using Lumia 950 XL are much better than using Lumia 535 and are better or comparable to the results of theodolite intersection with least squares technique (LST). Finally, it can be stated that the digital cameras of smart phones are suitable for close range photogrammetry applications according to accuracy, costs and flexibility.

scholarly journals Evaluation of Long-Range Mobile Mapping System (MMS) and Close-Range Photogrammetry for Deformation Monitoring. A Case Study of Cortes de Pallás in Valencia (Spain)

2020 ◽  
Vol 10 (19) ◽  
pp. 6831
Author(s):  
Francesco Di Stefano ◽  
Miriam Cabrelles ◽  
Luis García-Asenjo ◽  
José Luis Lerma ◽  
Eva Savina Malinverni ◽  
...  
Keyword(s):  
Long Range ◽  
New Technologies ◽  
3D Models ◽  
Deformation Monitoring ◽  
Mobile Mapping ◽  
Close Range Photogrammetry ◽  
Mapping System ◽  
Mobile Mapping System ◽  
Close Range ◽  
Landslide Deformation

This contribution describes the methodology applied to evaluate the suitability of a Long-Range Mobile Mapping System to be integrated with other techniques that are currently used in a large and complex landslide deformation monitoring project carried out in Cortes de Pallás, in Valencia (Spain). Periodical geodetic surveys provide a reference frame realized by 10 pillars and 15 additional check points placed in specific points of interest, all with millimetric accuracy. The combined use of Close-Range Photogrammetry provides a well-controlled 3D model with 1–3 cm accuracy, making the area ideal for testing new technologies. Since some zones of interest are usually obstructed by construction, trees, or lamp posts, a possible solution might be the supplementary use of dynamic scanning instruments with the mobile mapping solution Kaarta Stencil 2 to collect the missing data. However, the reliability of this technology has to be assessed and validated before being integrated into the existing 3D models in the well-controlled area of Cortes de Pallás. The results of the experiment show that the accuracy achieved are compatible with those obtained from Close-Range Photogrammetry and can also be safely used to supplement image-based information for monitoring with 3–8 cm overall accuracy.

scholarly journals CLOSE-RANGE PHOTOGRAMMETRY METHOD FOR SF6 GAS INSULATED LINE (GIL) DEFORMATION MONITORING

2021 ◽  
Vol XLIII-B2-2021 ◽  
pp. 503-510
Author(s):  
K. N. Fauzan ◽  
D. Suwardhi ◽  
A. Murtiyoso ◽  
I. Gumilar ◽  
T. P. Sidiq
Keyword(s):  
Data Processing ◽  
Data Acquisition ◽  
Field Data ◽  
Planning Process ◽  
Deformation Monitoring ◽  
Technical Data ◽  
Close Range Photogrammetry ◽  
Observation Methods ◽  
Average Accuracy ◽  
Close Range

Abstract. Close-Range Photogrammetry (CRP) technology advanced rapidly along with the development of camera sensors. CRP has many advantages over other methods in terms of technical data acquisition, product quality, and cost. Because of these advantages, the CRP method can be used in various applications. In this study, the CRP method is used to monitor the deformation of the SF6 Gas Insulated Line (GIL) object between two substations of the Indonesian National Electricity Service in Kuningan Barat, South Jakarta. Planning was carried out with a simulation using 3D field data obtained from reconnaissance process. During the survey, photo data was collected using a smartphone and processed to form a 3D model. The simulation produced a configuration of control points, check points, and camera stations that have the best Strength of Figure (SoF) values. In the planning process, camera pre-calibration is carried out to get the best camera orientation parameter values from several experiments. The planning results are used in the next stage, namely field data acquisition and data processing. The data acquisition process was carried out for two sessions. This is done to see the changes in coordinates that occur between these sessions. Data processing was carried out by following the classical photogrammetric stages. The results obtained from this study are the average accuracy produced by Close-Range Photogrammetry method for measuring deformation which is below a tolerance of 3 mm. With this method, deformation measurements can be carried out quickly, accurately, and at a relatively lower cost than other observation methods.

scholarly journals Total Least Squares Spline Approximation

Mathematics ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 462 ◽  
Author(s):  
Frank Neitzel ◽  
Nikolaj Ezhov ◽  
Svetozar Petrovic
Keyword(s):  
Least Squares ◽  
Spline Approximation ◽  
Functional Model ◽  
Total Least Squares ◽  
Deformation Monitoring ◽  
Random Errors ◽  
Laser Scanners ◽  
Engineering Geodesy ◽  
Continuous Curvature ◽  
Cubic Polynomials

Spline approximation, using both values y i and x i as observations, is of vital importance for engineering geodesy, e.g., for approximation of profiles measured with terrestrial laser scanners, because it enables the consideration of arbitrary dispersion matrices for the observations. In the special case of equally weighted and uncorrelated observations, the resulting error vectors are orthogonal to the graph of the spline function and hence can be utilized for deformation monitoring purposes. Based on a functional model that uses cubic polynomials and constraints for continuity, smoothness and continuous curvature, the case of spline approximation with both the values y i and x i as observations is considered. In this case, some of the columns of the functional matrix contain observations and are thus subject to random errors. In the literature on mathematics and statistics this case is known as an errors-in-variables (EIV) model for which a so-called “total least squares” (TLS) solution can be computed. If weights for the observations and additional constraints for the unknowns are introduced, a “constrained weighted total least squares” (CWTLS) problem is obtained. In this contribution, it is shown that the solution for this problem can be obtained from a rigorous solution of an iteratively linearized Gauss-Helmert (GH) model. The advantage of this model is that it does not impose any restrictions on the form of the functional relationship between the involved quantities. Furthermore, dispersion matrices can be introduced without limitations, even the consideration of singular ones is possible. Therefore, the iteratively linearized GH model can be regarded as a generalized approach for solving CWTLS problems. Using a numerical example it is demonstrated how the GH model can be applied to obtain a spline approximation with orthogonal error vectors. The error vectors are compared with those derived from two least squares (LS) approaches.

Development of a 3D Full-Field Monitoring System for Large-Scale Static Deformation Based on close Range Photogrammetry

2012 ◽  
Vol 468-471 ◽  
pp. 1074-1077
Author(s):  
Jian Wei Liu ◽  
Zhi Qiang Jiang ◽  
Yuan Peng Liu ◽  
Hao Hu
Keyword(s):  
Large Scale ◽  
Power Transmission ◽  
Deformation Monitoring ◽  
Static Deformation ◽  
Transmission Tower ◽  
Full Field ◽  
Monitoring Task ◽  
Close Range Photogrammetry ◽  
Displacement Sensors ◽  
Close Range

A non-contact deformation measurement method is proposed for monitoring the 3D full-field static deformation of large-scale structures under loads, which could not be achieved by traditional displacement sensors and resistance strain gauges. This method is based on the close range photogrammetry technology. By tracking and comparing the 3D coordinates of the targets between different epoch, the load–deformation diagram in 3D form for the whole large-scale structure is obtained, which is valuable for further mechanical behavior analysis. Real-scale power transmission tower experiment shows that the proposed method can fulfill the efficiency and accuracy requirement in large-scale full-field deformation monitoring task

scholarly journals Application of Structural Deformation Monitoring Based on Close-Range Photogrammetry Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jun Hu ◽  
Ensheng Liu ◽  
Jiayu Yu
Keyword(s):  
Coordinate System ◽  
Linear Transformation ◽  
Measurement Methods ◽  
Deformation Monitoring ◽  
Structural Deformation ◽  
Measurement Point ◽  
Measuring Point ◽  
Close Range Photogrammetry ◽  
Close Range ◽  
Load Action

The problem of structural deformation monitoring has always been a research hotspot in engineering architecture. Research on structural deformation monitoring is the main way to solve the risk of engineering construction. Based on using close-range photogrammetry technology to monitor structural deformation, combining with image recognition technology to collect and process image data, and using the conditions of direct linear transformation and collinear equation to calculate based on the extracted coordinates of the measuring point, finally, according to the coordinates of the measuring point and the deflection value of the bridge structure, the study is carried out. Experiment: first, five sets of data are used to calibrate the close-range photogrammetry equipment of measurement point accuracy are analyzed, then the bridge piers and the measurement point coordinates, the lasso, under different load on the accuracy of close-range photogrammetry technology is analyzed, according to the relevant data of the error of the close-range photogrammetry technology are analyzed, and through the calculation of different measurement methods to analyze the direct linear transformation manifested in the article. The final results show that the X-axis coordinate range of the measured points in the auxiliary spatial coordinate system is 25∼40, Y-axis coordinate range is 8∼36, and Z-axis coordinate range is 10∼35. The coordinates of measuring points of bridge cables are distributed in the fourth quadrant of the spatial coordinate system. The accuracy values of all coordinates of the measuring points under the close-range photogrammetry equipment are less than 0.1 mm, indicating that the close-range photogrammetry equipment has a good effect on the calibration of measuring points, and the error generated when the load action of each measuring point of the bridge cable is 10 N is greater than that generated when the load action is 20 N. In different calculation and measurement methods, the results obtained by total station measurement and calculation method are reduced by about 0.04∼0.07 m compared with the actual value; the results obtained by direct linear transformation method are increased by about 0.02∼0.04 m compared with the actual value; and the results obtained by other measurement and calculation methods are increased by about 0.04∼0.06 m compared with the actual value.

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