The progressive awareness of public administrations and society towards the necessity of preservi... more The progressive awareness of public administrations and society towards the necessity of preserving the cultural heritage, particularly rock art, has become more and more important in developed countries. In Galicia (northwest of Spain), there are many petroglyph remains that are seriously affected by a severe acceleration in degradation due to urban expansion. In this situation, actions focused on the preservation of these patrimonial elements have to be accomplished. These protection forms must be preceded by a previous step of exhaustive documentation of the prehistoric element, in order to register the conservation state of the element so that it can be contrasted with future observations or studies. The advances experimented by 3D digital techniques make possible to document rock art avoiding the inconveniences previously mentioned. The 3D digitalization of objects allows not only registering the metric and radiometric characteristics of objects, but also the diffusion and tran...
Universitario As Lagoas –Marcosende s/n 36200 Vigo Spain – (belenriveiro, parias, julia, firv, me... more Universitario As Lagoas –Marcosende s/n 36200 Vigo Spain – (belenriveiro, parias, julia, firv, merchisolla)@uvigo.es Commission V, WG V/2 ABSTRACT: This paper describes the project of the Close Range Photogrammetry and Remote Sensing Group, University of Vigo, Spain, involving historic arch bridges in Galicia, Spain. The first aim of this Project consists on building a database of the historic arch bridges in Galicia, documenting location, surroundings, geometry, singular characteristics, structural faults, building material and state of conservation. On the other side, a methodology is being designed to optimize measuring and analysing techniques: Close Range Photogrammetry and Laser Scanning as 3D modelling tools for geometry and cracks documentation (Arias et al, 2005), Ground Penetrating Radar for inner material characterization and zones description, and FEM as structural analysis tool to establish stress distribution compatible with the detected damages, allowing identifying i...
Computer-Aided Civil and Infrastructure Engineering, 2014
ABSTRACT This article proposes a method to semiautomatically extract the road axis through a mobi... more ABSTRACT This article proposes a method to semiautomatically extract the road axis through a mobile LiDAR system, a recent popular technology for transportation-related applications, road estimation and even to enhance driver safety. In particular, the approach developed has two components: (1) the feature extraction from LiDAR data to model the road axis, and (2) the estimation of the horizontal alignment that meets the requirements and practice for a transportation authority. Given the massive and complex character of the data captured by the system, a hierarchical (coarse-to-fine) and robust strategy based on segmentation, parameterization and filtering, which determine the road centerline together with the geometric elements that compose its horizontal alignment, such as straight lines, circular arcs, and clothoids, has been developed and implemented. Test results using a simulated and a real data are discussed and validated. The experimental results obtained with real cases guarantying relative accuracies under 2%, being a useful approach to produce accurate estimations of the horizontal geometric features of the road alignment.
Proceedings of the 2012 18th International Conference on Virtual Systems and Multimedia, VSMM 2012: Virtual Systems in the Information Society, 2012
ABSTRACT The use of Building Information Models (BIM) for energy analysis is becoming a common ap... more ABSTRACT The use of Building Information Models (BIM) for energy analysis is becoming a common application, supported by the appearance of standards and regulations restricting energy consumption and energy efficiency in the building sector. BIMs from already built buildings are being generated with the help of high-technology devices such as laser scanners, which acquire the physical reality of a scene with high accuracy in a short time. However, the environment of the building, and especially surfaces producing shades, which are essential for the performance of meaningful energy studies, is usually forgotten as the focus is set on the representation of complex geometries. With the aim of generating a BIM able to be subjected to energy analysis, this paper presents a working methodology including data acquisition with a laser scanner, shape extraction of the building itself and its surroundings, and conversion of extracted elements, including shade surfaces, to BIM components.
ABSTRACT This paper presents a working methodology for the automatic generation of as-built Build... more ABSTRACT This paper presents a working methodology for the automatic generation of as-built Building Information Models (BIMs) including shade surfaces able to be subjected to solar analysis, given the great effect that shading has in the energy consumption of the building. This methodology goes from data acquisition with a laser scanner, to the shape extraction of the building and its surroundings from the acquired data through curvature analysis and Region Growing algorithms, to end with the conversion of the extracted elements, which define both the building and the shading elements, to BIM components. BIM is defined in gbXML language, which was especially designed to be used in energy software, so that the generated BIM with shades can be directly introduced in energy analysis software.
Journal of Performance of Constructed Facilities, 2014
ABSTRACT Monitoring of breakwaters is a key aspect to prevent failures that affect the safety and... more ABSTRACT Monitoring of breakwaters is a key aspect to prevent failures that affect the safety and quality of service. Unmanned aerial vehicle (UAV) photogrammetry gives low-cost and accurate geometric data, flexibility, and productivity to perform aerial surveys, although the weather conditions restrict flights for wind speeds above 50 km/h (the Mikrokopter system). Despite the promising potential of these systems, its ability to monitor movement of cubes in breakwaters has not yet proven. The UAV photogrammetry is tested for the research reported in this paper in the Baiona breakwaters (northwestern Spain). A SD of 0.026 m is obtained from the point cloud. The detection limit of the system is evaluated and rotations lower than 1° could be detected. This value is calculated from the measurable differences in height values after the virtual rotation of a single cube. The system provides the exact position where the movement of the cube is produced and can be easily integrated with geographic information system–based management systems.
ABSTRACT Ground-penetrating radar (GPR) is a recommendable and cost-effective non-destructive tec... more ABSTRACT Ground-penetrating radar (GPR) is a recommendable and cost-effective non-destructive technique for measuring the thickness of pavement layers because data acquisition can take place at normal traffic speeds. On the other hand, the large amount of data collected is difficult to process. Given that processing is conducted by qualified practitioners, it is a key to obtain software tools that allow for accurate thickness measurements and fast processing times. This paper presents a new semi-automatic program for the processing and visualisation of GPR data to measure pavement thicknesses. The results showed that an optimisation in the execution time allowed for a near-immediate response in data processing even when dealing with large data sets. Different data set lengths, ranging from 100 m to 20 km, were analysed, and the processing times required to complete the entire process were examined taking into account three different hardware configurations (i3, i5 and i7 processors). In all cases, the processing times did not exceed 30 s. An additional test was performed to evaluate the reproducibility of the algorithm on a well-defined and preconditioned concrete asphalt course. Furthermore, the visualisation application allows for the georeferencing of the field GPR data by using additional GPS data.
The progressive awareness of public administrations and society towards the necessity of preservi... more The progressive awareness of public administrations and society towards the necessity of preserving the cultural heritage, particularly rock art, has become more and more important in developed countries. In Galicia (northwest of Spain), there are many petroglyph remains that are seriously affected by a severe acceleration in degradation due to urban expansion. In this situation, actions focused on the preservation of these patrimonial elements have to be accomplished. These protection forms must be preceded by a previous step of exhaustive documentation of the prehistoric element, in order to register the conservation state of the element so that it can be contrasted with future observations or studies. The advances experimented by 3D digital techniques make possible to document rock art avoiding the inconveniences previously mentioned. The 3D digitalization of objects allows not only registering the metric and radiometric characteristics of objects, but also the diffusion and tran...
Universitario As Lagoas –Marcosende s/n 36200 Vigo Spain – (belenriveiro, parias, julia, firv, me... more Universitario As Lagoas –Marcosende s/n 36200 Vigo Spain – (belenriveiro, parias, julia, firv, merchisolla)@uvigo.es Commission V, WG V/2 ABSTRACT: This paper describes the project of the Close Range Photogrammetry and Remote Sensing Group, University of Vigo, Spain, involving historic arch bridges in Galicia, Spain. The first aim of this Project consists on building a database of the historic arch bridges in Galicia, documenting location, surroundings, geometry, singular characteristics, structural faults, building material and state of conservation. On the other side, a methodology is being designed to optimize measuring and analysing techniques: Close Range Photogrammetry and Laser Scanning as 3D modelling tools for geometry and cracks documentation (Arias et al, 2005), Ground Penetrating Radar for inner material characterization and zones description, and FEM as structural analysis tool to establish stress distribution compatible with the detected damages, allowing identifying i...
Computer-Aided Civil and Infrastructure Engineering, 2014
ABSTRACT This article proposes a method to semiautomatically extract the road axis through a mobi... more ABSTRACT This article proposes a method to semiautomatically extract the road axis through a mobile LiDAR system, a recent popular technology for transportation-related applications, road estimation and even to enhance driver safety. In particular, the approach developed has two components: (1) the feature extraction from LiDAR data to model the road axis, and (2) the estimation of the horizontal alignment that meets the requirements and practice for a transportation authority. Given the massive and complex character of the data captured by the system, a hierarchical (coarse-to-fine) and robust strategy based on segmentation, parameterization and filtering, which determine the road centerline together with the geometric elements that compose its horizontal alignment, such as straight lines, circular arcs, and clothoids, has been developed and implemented. Test results using a simulated and a real data are discussed and validated. The experimental results obtained with real cases guarantying relative accuracies under 2%, being a useful approach to produce accurate estimations of the horizontal geometric features of the road alignment.
Proceedings of the 2012 18th International Conference on Virtual Systems and Multimedia, VSMM 2012: Virtual Systems in the Information Society, 2012
ABSTRACT The use of Building Information Models (BIM) for energy analysis is becoming a common ap... more ABSTRACT The use of Building Information Models (BIM) for energy analysis is becoming a common application, supported by the appearance of standards and regulations restricting energy consumption and energy efficiency in the building sector. BIMs from already built buildings are being generated with the help of high-technology devices such as laser scanners, which acquire the physical reality of a scene with high accuracy in a short time. However, the environment of the building, and especially surfaces producing shades, which are essential for the performance of meaningful energy studies, is usually forgotten as the focus is set on the representation of complex geometries. With the aim of generating a BIM able to be subjected to energy analysis, this paper presents a working methodology including data acquisition with a laser scanner, shape extraction of the building itself and its surroundings, and conversion of extracted elements, including shade surfaces, to BIM components.
ABSTRACT This paper presents a working methodology for the automatic generation of as-built Build... more ABSTRACT This paper presents a working methodology for the automatic generation of as-built Building Information Models (BIMs) including shade surfaces able to be subjected to solar analysis, given the great effect that shading has in the energy consumption of the building. This methodology goes from data acquisition with a laser scanner, to the shape extraction of the building and its surroundings from the acquired data through curvature analysis and Region Growing algorithms, to end with the conversion of the extracted elements, which define both the building and the shading elements, to BIM components. BIM is defined in gbXML language, which was especially designed to be used in energy software, so that the generated BIM with shades can be directly introduced in energy analysis software.
Journal of Performance of Constructed Facilities, 2014
ABSTRACT Monitoring of breakwaters is a key aspect to prevent failures that affect the safety and... more ABSTRACT Monitoring of breakwaters is a key aspect to prevent failures that affect the safety and quality of service. Unmanned aerial vehicle (UAV) photogrammetry gives low-cost and accurate geometric data, flexibility, and productivity to perform aerial surveys, although the weather conditions restrict flights for wind speeds above 50 km/h (the Mikrokopter system). Despite the promising potential of these systems, its ability to monitor movement of cubes in breakwaters has not yet proven. The UAV photogrammetry is tested for the research reported in this paper in the Baiona breakwaters (northwestern Spain). A SD of 0.026 m is obtained from the point cloud. The detection limit of the system is evaluated and rotations lower than 1° could be detected. This value is calculated from the measurable differences in height values after the virtual rotation of a single cube. The system provides the exact position where the movement of the cube is produced and can be easily integrated with geographic information system–based management systems.
ABSTRACT Ground-penetrating radar (GPR) is a recommendable and cost-effective non-destructive tec... more ABSTRACT Ground-penetrating radar (GPR) is a recommendable and cost-effective non-destructive technique for measuring the thickness of pavement layers because data acquisition can take place at normal traffic speeds. On the other hand, the large amount of data collected is difficult to process. Given that processing is conducted by qualified practitioners, it is a key to obtain software tools that allow for accurate thickness measurements and fast processing times. This paper presents a new semi-automatic program for the processing and visualisation of GPR data to measure pavement thicknesses. The results showed that an optimisation in the execution time allowed for a near-immediate response in data processing even when dealing with large data sets. Different data set lengths, ranging from 100 m to 20 km, were analysed, and the processing times required to complete the entire process were examined taking into account three different hardware configurations (i3, i5 and i7 processors). In all cases, the processing times did not exceed 30 s. An additional test was performed to evaluate the reproducibility of the algorithm on a well-defined and preconditioned concrete asphalt course. Furthermore, the visualisation application allows for the georeferencing of the field GPR data by using additional GPS data.
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Papers by Pedro Arias