scholarly journals Evaluation of Photogrammetry and Inclusion of Control Points: Significance for Infrastructure Monitoring

Data ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 42 ◽  
Author(s):  
Renee Oats ◽  
Rudiger Escobar-Wolf ◽  
Thomas Oommen
Keyword(s):  
Laser Scanning ◽  
Retaining Wall ◽  
Control Point ◽  
Wall Structure ◽  
Control Points ◽  
Point Selection ◽  
Cloud Data ◽  
Infrastructure Monitoring ◽  
Mode Behavior ◽  
The Impact

Structure from Motion (SfM)/Photogrammetry is a powerful mapping tool in extracting three-dimensional (3D) models from photographs. This method has been applied to a range of applications, including monitoring of infrastructure systems. This technique could potentially become a substitute, or at least a complement, for costlier approaches such as laser scanning for infrastructure monitoring. This study expands on previous investigations, which utilize photogrammetry point cloud data to measure failure mode behavior of a retaining wall model, emphasizing further robust spatial testing. In this study, a comparison of two commonly used photogrammetry software packages was implemented to assess the computing performance of the method and the significance of control points in this approach. The impact of control point selection, as part of the photogrammetric modeling processes, was also evaluated. Comparisons between the two software tools reveal similar performances in capturing quantitative changes of a retaining wall structure. Results also demonstrate that increasing the number of control points above a certain number does not, necessarily, increase 3D modeling accuracies, but, in some cases, their spatial distribution can be more critical. Furthermore, errors in model reproducibility, when compared with total station measurements, were found to be spatially correlated with the arrangement of control points.

scholarly journals TECHNIQUE OF AUTOMATIC MOBILE LASER SCANNING DATA ADJUSTMENT

2021 ◽  
Vol 26 (4) ◽  
pp. 5-23
Author(s):  
Maxim A. Altyntsev ◽  
◽  
Karkokli Hamid Majid Saber ◽  
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Control Point ◽  
Main Step ◽  
Control Points ◽  
Large Area ◽  
Road Signs ◽  
Automatic Mode ◽  
Building Walls ◽  
Data Adjustment

Adjustment is a main step in the preliminary processing of mobile laser scanning (MLS) data. As a result of this step, a point cloud is generated in a certain coordinate system. The modern software, provided with the corresponding surveying system, is capable of performing in automatic mode most stages of MLS data adjustment obtained for territories with different quantity of buildings. With a suf-ficient number of vertically arranged planar objects, such as building walls, the algorithms embedded in the software provide a high accuracy of relative adjustment, which consists in calculating and ap-plying corrections for trajectories obtained with re-scanning the same area. Absolute adjustment can also be carried out automatically, subject to the rules for placing control points in order to automatically detect them. This kind of adjustment involves transforming a point cloud with using control point coordinates measured with more accurate surveying methods. The accuracy of automatic relative adjustment can be significantly reduced with the almost complete absence of vertical flat objects. In this case, it is necessary to develop additional adjustment techniques capable of using not only flat objects of a large area, but also vertical objects, such as road signs and poles. Comprehensive technique of MLS data adjustment, which can use information on the position of road signs and poles for territories with an insufficient number of vertical flat objects is proposed. The accuracy estimation of both the relative and absolute MLS data adjustment according to the proposed technique was carried out. The choice of the required control point density for territories with different quantity of buildings is explained.

scholarly journals Estimating Control Points for B-Spline Surfaces Using Fully Populated Synthetic Variance–Covariance Matrices for TLS Point Clouds

2021 ◽  
Vol 13 (16) ◽  
pp. 3124
Author(s):  
Jakob Raschhofer ◽  
Gabriel Kerekes ◽  
Corinna Harmening ◽  
Hans Neuner ◽  
Volker Schwieger
Keyword(s):  
Laser Scanning ◽  
Point Clouds ◽  
Covariance Matrices ◽  
Geometric Modelling ◽  
Deformation Analysis ◽  
Control Points ◽  
B Splines ◽  
Spline Surfaces ◽  
Standard Deviations ◽  
The Impact

A flexible approach for geometric modelling of point clouds obtained from Terrestrial Laser Scanning (TLS) is by means of B-splines. These functions have gained some popularity in the engineering geodesy as they provide a suitable basis for a spatially continuous and parametric deformation analysis. In the predominant studies on geometric modelling of point clouds by B-splines, uncorrelated and equally weighted measurements are assumed. Trying to overcome this, the elementary errors theory is applied for establishing fully populated covariance matrices of TLS observations that consider correlations in the observed point clouds. In this article, a systematic approach for establishing realistic synthetic variance–covariance matrices (SVCMs) is presented and afterward used to model TLS point clouds by B-splines. Additionally, three criteria are selected to analyze the impact of different SVCMs on the functional and stochastic components of the estimation results. Plausible levels for variances and covariances are obtained using a test specimen of several dm—dimension. It is used to identify the most dominant elementary errors under laboratory conditions. Starting values for the variance level are obtained from a TLS calibration. The impact of SVCMs with different structures and different numeric values are comparatively investigated. Main findings of the paper are that for the analyzed object size and distances, the structure of the covariance matrix does not significantly affect the location of the estimated surface control points, but their precision in terms of the corresponding standard deviations. Regarding the latter, properly setting the main diagonal terms of the SVCM is of superordinate importance compared to setting the off-diagonal ones. The investigation of some individual errors revealed that the influence of their standard deviation on the precision of the estimated parameters is primarily dependent on the scanning distance. When the distance stays the same, one-sided influences on the precision of the estimated control points can be observed with an increase in the standard deviations.

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 Annular Neighboring Points Distribution Analysis: A Novel PLS Stem Point Cloud Preprocessing Algorithm for DBH Estimation

2020 ◽  
Vol 12 (5) ◽  
pp. 808 ◽  
Author(s):  
Jialong Duanmu ◽  
Yanqiu Xing
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
High Efficiency ◽  
Mean Squared Error ◽  
Absolute Error ◽  
Estimation Accuracy ◽  
Distribution Analysis ◽  
Cloud Data ◽  
The Impact

Personal laser scanning (PLS) has significant potential for estimating the in-situ diameter of breast height (DBH) with high efficiency and precision, which improves the understanding of forest structure and aids in building carbon cycle models in the big data era. PLS collects more complete stem point cloud data compared with the present laser scanning technology. However, there is still no significant advantage of DBH estimation accuracy. Because the error caused by merging different point cloud fragments has not yet been eliminated, overlapping and inaccurate co-registered point cloud fragments are often inevitable, which are usually the leading error sources of PLS-based DBH estimation. In this study, a novel pre-processing algorithm named annular neighboring points distribution analysis (ANPDA) was developed to improve PLS-based DBH estimation accuracy. To reduce the impact of inaccurately co-registered point cloud fragments, ANPDA identified outliers through iterative removal of outermost points and analyzing the distribution of annular neighboring points. Six plots containing 247 trees under different forest conditions were selected to evaluate the ANPDA. Results showed that in the six plots, error reductions of 53.80–87.13% for bias, 38.82–57.30% for mean absolute error (MAE), and 27.17–56.02% for root mean squared error (RMSE) were achieved after applying ANPDA. These results confirmed that ANPDA was generally effective for improving PLS-based DBH estimation accuracy. It appeared that ANPDA could be conveniently fused with an automatic PLS-based DBH estimation process as a preprocessing algorithm. Furthermore, it has the potential to predict and warn operators of potential large errors during hierarchical semi-automatic DBH estimation.

scholarly journals Landscape monitoring of post-industrial areas using LiDAR and GIS technology

2015 ◽  
Vol 64 (1) ◽  
pp. 125-137 ◽  
Author(s):  
Piotr Wężyk ◽  
Marta Szostak ◽  
Wojciech Krzaklewski ◽  
Marek Pająk ◽  
Marcin Pierzchalski ◽  
...  
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Point Clouds ◽  
Slope Aspect ◽  
Gis Technology ◽  
Industrial Areas ◽  
Cloud Data ◽  
Post Industrial ◽  
The Impact ◽  
Spoil Heaps

Abstract The quarrying industry is changing the local landscape, forming deep open pits and spoil heaps in close proximity to them, especially lignite mines. The impact can include toxic soil material (low pH, heavy metals, oxidations etc.) which is the basis for further reclamation and afforestation. Forests that stand on spoil heaps have very different growth conditions because of the relief (slope, aspect, wind and rainfall shadows, supply of solar energy, etc.) and type of soil that is deposited. Airborne laser scanning (ALS) technology deliver point clouds (XYZ) and derivatives as raster height models (DTM, DSM, nDSM=CHM) which allow the reception of selected 2D and 3D forest parameters (e.g. height, base of the crown, cover, density, volume, biomass, etc). The automation of ALS point cloud processing and integrating the results into GIS helps forest managers to take appropriate decisions on silvicultural treatments in areas with failed plantations (toxic soil, droughts on south-facing slopes; landslides, etc.) or as regular maintenance. The ISOK country-wide project ongoing in Poland will soon deliver ALS point cloud data which can be successfully used for the monitoring and management of many thousands of hectares of destroyed post-industrial areas which according to the law, have to be afforested and transferred back to the State Forest.

scholarly journals Corridor Mapping of Sandy Coastal Foredunes with UAS Photogrammetry and Mobile Laser Scanning

2019 ◽  
Vol 11 (11) ◽  
pp. 1352 ◽  
Author(s):  
Alphonse Nahon ◽  
Pere Molina ◽  
Marta Blázquez ◽  
Jennifer Simeon ◽  
Sylvain Capo ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Management Practices ◽  
Control Point ◽  
Unmanned Aircraft ◽  
Ground Control ◽  
Scanning System ◽  
Control Points ◽  
Ground Control Points ◽  
Spatial Coverage ◽  
Mean Square Errors

Recurrent monitoring of sandy beaches and of the dunes behind them is needed to improve the scientific knowledge on their dynamics as well as to develop sustainable management practices of those valuable landforms. Unmanned Aircraft Systems (UAS) are sought as a means to fulfill this need, especially leveraged by photogrammetric and LiDAR-based mapping methods and technology. The present study compares different strategies to carry UAS photogrammetric corridor mapping over linear extensions of sandy shores. In particular, we present results on the coupling of a UAS with a mobile laser scanning system, operating simultaneously in Cap Ferret, SW France. This aerial-terrestrial tandem enables terrain reconstruction with kinematic ground control points, thus largely avoiding the deployment of surveyed ground control points on the non-stable sandy ground. Results show how these three techniques—mobile laser scanning, photogrammetry based on ground control points, and photogrammetry based on kinematic ground control points—deliver accurate (i.e., root mean square errors < 15 cm) 3D reconstruction of beach-to-dune transition areas, the latter being performed at lower survey and logistic costs, and with enhanced spatial coverage capabilities. This study opens the gate for exploring longer (hundreds of kilometers) shoreline dynamics with ground-control-point-free air and ground mapping techniques.

scholarly journals The Study on Construction Technique about The Reinforced Concrete Retaining Wall’s Lateral Displacement Repairing

2018 ◽  
Vol 175 ◽  
pp. 02006
Author(s):  
HAN Shang Yu ◽  
LI Kai Ren ◽  
Qiu Fang
Keyword(s):  
Quality Control ◽  
Reinforced Concrete ◽  
Lateral Displacement ◽  
Retaining Wall ◽  
Wall Structure ◽  
Control Points ◽  
Construction Process ◽  
Lateral Deformation ◽  
Construction Technique

Based on the stress characteristics and the composition of lateral deformation about retaining wall structure, a kind of lateral displacement repairing construction technique of reinforced concrete retaining wall is proposed. Meanwhile, the process principle, construction process and quality control points of the technique are systematically analyzed in this paper. From the application effect of site engineering, the construction proposed in the paper has good engineering benefit and promotion value.

scholarly journals Using Recycled Material from the Paper Industry as a Backfill Material for Retaining Walls near Railway Lines

2021 ◽  
Vol 13 (2) ◽  
pp. 979
Author(s):  
Karmen Fifer Bizjak ◽  
Barbara Likar ◽  
Stanislav Lenart
Keyword(s):  
Retaining Wall ◽  
Paper Industry ◽  
Time Lag ◽  
Wall Structure ◽  
Railway Line ◽  
Backfill Material ◽  
Geotechnical Structures ◽  
Sludge Ash ◽  
The Impact ◽  
Recycled Material

The construction industry uses a large amount of natural virgin material for different geotechnical structures. In Europe alone, 11 million tonnes of solid waste is generated per year as a result of the production of almost 100 million tonnes of paper. The objective of this research is to develop a new geotechnical composite from residues of the deinking paper industry and to present its practical application, e.g., as a backfill material behind a retaining structure. After different mixtures were tested in a laboratory, the technology was validated by building a pilot retaining wall structure in a landslide region near a railway line. It was confirmed that a composite with 30% deinking sludge and 70% deinking sludge ash had a high enough strength but experienced some deformations before failure. Special attention was paid to the impact of transport, which, due to the time lag between the mixing and installation of the composite, significantly reduced its strength. The pilot retaining wall structure promotes the use of recycled materials with a sustainable design, while adhering to government-mandated measures.

scholarly journals Robust and automatic modeling of tunnel structures based on terrestrial laser scanning measurement

2019 ◽  
Vol 15 (11) ◽  
pp. 155014771988488 ◽  
Author(s):  
Xiangyang Xu ◽  
Hao Yang ◽  
Boris Kargoll
Keyword(s):  
Laser Scanning ◽  
Large Scale ◽  
Control Point ◽  
Spline Approximation ◽  
Terrestrial Laser Scanning ◽  
Ordinary Least Squares ◽  
Deformation Monitoring ◽  
B Spline ◽  
Cloud Data ◽  
Data Gaps

The terrestrial laser scanning technology is increasingly applied in the deformation monitoring of tunnel structures. However, outliers and data gaps in the terrestrial laser scanning point cloud data have a deteriorating effect on the model reconstruction. A traditional remedy is to delete the outliers in advance of the approximation, which could be time- and labor-consuming for large-scale structures. This research focuses on an outlier-resistant and intelligent method for B-spline approximation with a rank (R)-based estimator, and applies to tunnel measurements. The control points of the B-spline model are estimated specifically by means of the R-estimator based on Wilcoxon scores. A comparative study is carried out on rank-based and ordinary least squares methods, where the Hausdorff distance is adopted to analyze quantitatively for the different settings of control point number of B-spline approximation. It is concluded that the proposed method for tunnel profile modeling is robust against outliers and data gaps, computationally convenient, and it does not need to determine extra tuning constants.

scholarly journals Effect of Land Control Points Spatial Allocation for the Image Registration of Remote Sensing Images

2019 ◽  
Vol 8 (2) ◽  
pp. 6483-6488
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Image Registration ◽  
Control Point ◽  
Ground Control ◽  
Control Points ◽  
Point Distribution ◽  
Thiessen Polygon ◽  
Land Control ◽  
The Impact

With the development in space technology, new remote sensing satellites are launched around the world tremendously. The high resolution camera gives high resolution satellite images and the large data is produced by remote sensors persistently. Because of high efficiency, the vast inclusion of data with not being restricted by the spatial parameter, satellite representation winds up one of the imperative way to obtain geospatial data. With this data, the obtaining of land control points is essential in the image registration and geometric improvement of satellite pictures. In this research work, the influence of the quantity and geographical distribution of land ground control point in image registration and accurateness is examine through Voronoi Diagram (Thiessen polygon). A simulation investigation was carried out using remote sensing pictures to analyze the impact of distributed patterns of land control points on image registration and correction. The corrected values are measured by square root mean error (SRME) and with residual separations. It exhibits that the center distribution gives the most reduced SRME. Additionally, demonstrates that the land control point distribution in the center of image is less distorted in comparison to land control points positioned at borders and corners. Subsequently, the centralized uniform distribution of ground control points shows better results taking into consideration the overall deformation rate on the complete image registration.

Sign in / Sign up

Export Citation Format

Share Document