Automated point clouds processing for deformation monitoring

The weather conditions and the operation load are causing changes in the spatial position and in the shape of engineering constructions, which affects their static and dynamic function and reliability. Because these facts, geodetic measurements are integral parts of engineering structures diagnosis.The advantage of terrestrial laser scanning (TLS) over conventional surveying methods is the efficiency of spatial data acquisition. TLS allows contactless determining the spatial coordinates of points lying on the surface on the measured object. The scan rate of current scanners (up to 1 million of points/s) allows significant reduction of time, necessary for the measurement; respectively increase the quantity of obtained information about the measured object. To increase the accuracy of results, chosen parts of the monitored construction can be approximated by single geometric entities using regression. In this case the position of measured point is calculated from tens or hundreds of scanned points.This paper presents the possibility of deformation monitoring of engineering structures using the technology of TLS. For automated data processing was developed an application based on Matlab®, Displacement_TLS. The operation mode, the basic parts of this application and the calculation of displacements are described.</p

Barcode based localization system in indoor environment

Nowadays, in the era of intelligent buildings, there is a need to create indoornavigation systems, what is steadily a challenge. QR (Quick Response) codesprovide accurate localization also in indoor environment, where other navigationtechniques (e.g. GPS) are not available. The paper deals with the issues of posi-tioning using QR codes, solved at the Department of Surveying, Faculty of CivilEngineering SUT in Bratislava. Operating principle of QR codes, description ofthe application for positioning in indoor environment based on OS Android forsmartphones are described

Plane segmentation from point clouds

Recently, attempts have been made to automate data acquisition, which is also related to efforts to automate data processing. The paper deals with the automation of terrestrial laser scanning data processing. The approaches for point cloud segmentation are briefly described. An algorithm based on random sample consensus is proposed for automated plane identification and plane segmentation from point clouds. The proposed approach was tested by processing point clouds; the results of the testing are also described. Based on the proposed algorithm, a standalone application for automated plane segmentation from laser scanner data using Matlab® software was developed

Automated point clouds processing for deformation monitoring

The weather conditions and the operation load are causing changes in the spatial position and in the shape of engineering constructions, which affects their static and dynamic function and reliability. Because these facts, geodetic measurements are integral parts of engineering structures diagnosis.The advantage of terrestrial laser scanning (TLS) over conventional surveying methods is the efficiency of spatial data acquisition. TLS allows contactless determining the spatial coordinates of points lying on the surface on the measured object. The scan rate of current scanners (up to 1 million of points/s) allows significant reduction of time, necessary for the measurement; respectively increase the quantity of obtained information about the measured object. To increase the accuracy of results, chosen parts of the monitored construction can be approximated by single geometric entities using regression. In this case the position of measured point is calculated from tens or hundreds of scanned points.This paper presents the possibility of deformation monitoring of engineering structures using the technology of TLS. For automated data processing was developed an application based on Matlab®, Displacement_TLS. The operation mode, the basic parts of this application and the calculation of displacements are described.</p

Automated Sphere Segmentation from Point Clouds

Nowadays huge datasets can be collected in a relatively short time. After capturing these data sets the next step is their processing. Automation of the processing steps can contribute to efficiency increase, to reduction of the time needed for processing, and to reduction of interactions of the user. The paper brings a short review of the most reliable methods for sphere segmentation. An innovative algorithm for automated detection of spheres and for estimating their parameters from 3D point clouds is introduced. The algorithm proposed was tested on complex point clouds. In the last part of the paper, the implementation of the algorithm proposed to a standalone application is described

Automation of Cylinder Segmentation from Point Cloud Data

The results of terrestrial laser scanning are point clouds, which are becoming an increasingly common initial digital representation of real-world objects. Since point clouds in the most cases represent a huge amount of data, automation of the processing steps is advisable. The paper brings a short review of the most reliable methods of cylinder extraction. An innovative algorithm is proposed for an automated detection of cylinders and also for estimating their parameters from 3D point cloud data. The method was tested on the complex point clouds of pipelines. The proposed algorithm was implemented to a standalone application based on MATLAB® software

Barcode based localization system in indoor environment

Nowadays, in the era of intelligent buildings, there is a need to create indoornavigation systems, what is steadily a challenge. QR (Quick Response) codesprovide accurate localization also in indoor environment, where other navigationtechniques (e.g. GPS) are not available. The paper deals with the issues of posi-tioning using QR codes, solved at the Department of Surveying, Faculty of CivilEngineering SUT in Bratislava. Operating principle of QR codes, description ofthe application for positioning in indoor environment based on OS Android forsmartphones are described

Spatial Data Analysis for Deformation Monitoring of Bridge Structures

Weather conditions and different operational loads often cause changes in essential parts of engineering structures, and this affects the static and dynamic behavior and reliability of these structures. Therefore, geodetic monitoring is an integral part of the diagnosis of engineering structures and provides essential information about the current state (condition) of the structure. The development of measuring instruments enables deformation analyses of engineering structures using non-conventional surveying methods. Nowadays, one of the most effective techniques for spatial data collection is terrestrial laser scanning (TLS). TLS is frequently used for data acquisition in cases where three-dimensional (3D) data with high resolution is needed. Using suitable data processing, TLS can be used for static deformation analysis of the structure being monitored. For dynamic deformation measurements (structural health monitoring) of bridge structures, ground-based radar interferometry and accelerometers are often used for vibration mode determination using spectral analysis of frequencies. This paper describes experimental deformation monitoring of structures performed using TLS and ground-based radar interferometry. The procedure of measurement, the analysis of the acquired spatial data, and the results of deformation monitoring are explained and described

Semi-Automated Segmentation of Geometric Shapes from Point Clouds

Building information models (BIM) in the civil industry are very popular nowadays. The basic information of these models is the 3D geometric model of a building structure. The most applied methodology to model the existing buildings is by generating 3D geometric information from point clouds provided by laser scanners. The fundamental principle of this methodology is the recognition of structures shaped in basic geometric primitives, e.g., planes, spheres, and cylinders. The basic premise of the efficiency of this methodology is the automation of detection, since manual segmentation of a point cloud can be challenging, time-consuming, and, therefore, inefficient. This paper presents a novel algorithm for the automated segmentation of geometric shapes in point clouds without needing pre-segmentation. With the designed algorithm, structures formed in three types of basic geometrical primitive can be identified and segmented: planar (e.g., walls, floors, ceilings), spherical (e.g., laser scanner reference targets), and cylindrical (e.g., columns, pillars, piping). The RANSAC paradigm partially inspires the proposed algorithm; however, various modifications must be made. The algorithm was tested on several point clouds and was compared with the standard RANSAC algorithm; this part is described in the last section of the paper. One of the tests was performed on a double cylinder-shaped test object, the parameters (radius and height) of this object were available with high accuracy (0.1 mm), and the differences between the known and estimated parameters were below 0.5 mm in each case, indicating the correctness of the proposed algorithm. Also, a comparison with the standard RANSAC algorithm was performed, where the algorithm proposed showed better results than the standard RANSAC algorithm. The segmentation quality was, on average, increased from 50% to 100%

Barcode based localization system in indoor environment

Nowadays, in the era of intelligent buildings, there is a need to create indoornavigation systems, what is steadily a challenge. QR (Quick Response) codesprovide accurate localization also in indoor environment, where other navigationtechniques (e.g. GPS) are not available. The paper deals with the issues of posi-tioning using QR codes, solved at the Department of Surveying, Faculty of CivilEngineering SUT in Bratislava. Operating principle of QR codes, description ofthe application for positioning in indoor environment based on OS Android forsmartphones are described