Automatic Extraction of Road Points from Airborne LiDAR Based on Bidirectional Skewness Balancing

Road extraction from Light Detection and Ranging (LiDAR) has become a hot topic over recent years. Nevertheless, it is still challenging to perform this task in a fully automatic way. Experiments are often carried out over small datasets with a focus on urban areas and it is unclear how these methods perform in less urbanized sites. Furthermore, some methods require the manual input of critical parameters, such as an intensity threshold. Aiming to address these issues, this paper proposes a method for the automatic extraction of road points suitable for different landscapes. Road points are identified using pipeline filtering based on a set of constraints defined on the intensity, curvature, local density, and area. We focus especially on the intensity constraint, as it is the key factor to distinguish between road and ground points. The optimal intensity threshold is established automatically by an improved version of the skewness balancing algorithm. Evaluation was conducted on ten study sites with different degrees of urbanization. Road points were successfully extracted in all of them with an overall completeness of 93%, a correctness of 83%, and a quality of 78%. These results are competitive with the state-of-the-artThis work has received financial support from the Consellería de Cultura, Educación e Ordenación Universitaria (accreditation 2019-2022 ED431G-2019/04 and reference competitive group 2019-2021, ED431C 2018/19) and the European Regional Development Fund (ERDF), which acknowledges the CiTIUS-Research Center in Intelligent Technologies of the University of Santiago de Compostela as a Research Center of the Galician University System. This work was also supported in part by Babcock International Group PLC (Civil UAVs Initiative Fund of Xunta de Galicia) and the Ministry of Education, Culture and Sport, Government of Spain (Grant Number TIN2016-76373-P)S

A fast and optimal pathfinder using airborne LiDAR data

Determining the optimal path between two points in a 3D point cloud is a problem that have been addressed in many different situations: from road planning and escape routes determination, to network routing and facility layout. This problem is addressed using different input information, being 3D point clouds one of the most valuables. Its main utility is to save costs, whatever the field of application is. In this paper, we present a fast algorithm to determine the least cost path in an Airborne Laser Scanning point cloud. In some situations, like finding escape routes for instance, computing the solution in a very short time is crucial, and there are not many works developed in this theme. State of the art methods are mainly based on a digital terrain model (DTM) for calculating these routes, and these methods do not reflect well the topography along the edges of the graph. Also, the use of a DTM leads to a significant loss of both information and precision when calculating the characteristics of possible routes between two points. In this paper, a new method that does not require the use of a DTM and is suitable for airborne point clouds, whether they are classified or not, is proposed. The problem is modeled by defining a graph using the information given by a segmentation and a Voronoi Tessellation of the point cloud. The performance tests show that the algorithm is able to compute the optimal path between two points by processing up to 678,820 points per second in a point cloud of 40,000,000 points and 16 km² of extensionThis work has received financial support from the Consellería de Cultura, Educación e Ordenación Universitaria (accreditation 2019-2022 ED431G-2019/04, reference competitive group 2019-2021, ED431C 2018/19) and the European Regional Development Fund (ERDF), which acknowledges the CiTIUS-Research Center in Intelligent Technologies of the University of Santiago de Compostela as a Research Center of the Galician University System. This work was also supported by the Ministry of Economy and Competitiveness, Government of Spain (Grant No. PID2019-104834 GB-I00). We also acknowledge the Centro de Supercomputación de Galicia (CESGA) for the use of their computersS

Fast Ground Filtering of Airborne LiDAR Data Based on Iterative Scan-Line Spline Interpolation

Over the last two decades, a wide range of applications have been developed from Light Detection and Ranging (LiDAR) point clouds. Most LiDAR-derived products require the distinction between ground and non-ground points. Because of this, ground filtering its being one of the most studied topics in the literature and robust methods are nowadays available. However, these methods have been designed to work with offline data and they are generally not well suited for real-time scenarios. Aiming to address this issue, this paper proposes an efficient method for ground filtering of airborne LiDAR data based on scan-line processing. In our proposal, an iterative 1-D spline interpolation is performed in each scan line sequentially. The final spline knots of a scan line are taken into account for the next scan line, so that valuable 2-D information is also considered without compromising computational efficiency. Points are labelled into ground and non-ground by analysing their residuals to the final spline. When tested against synthetic ground truth, the method yields a mean kappa value of 88.59% and a mean total error of 0.50%. Experiments with real data also show satisfactory results under visual inspection. Performance tests on a workstation show that the method can process up to 1 million points per second. The original implementation was ported into a low-cost development board to demonstrate its feasibility to run in embedded systems, where throughput was improved by using programmable logic hardware acceleration. Analysis shows that real-time filtering is possible in a high-end board prototype, as it can process the amount of points per second that current lightweight scanners acquire with low-energy consumptionThis work was supported by the Ministry of Education, Culture, and Sport, Government of Spain (Grant Number TIN2016-76373-P), the Consellería de Cultura, Educación e Ordenación Universitaria (accreditation 2016–2019, ED431G/08, and ED431C 2018/2019), and the European Union (European Regional Development Fund—ERDF)S

A Developer-Friendly “Open Lidar Visualizer and Analyser” for Point Clouds With 3D Stereoscopic View

Light detection and ranging is being a hot topic in the remote sensing field, and the development of robust point cloud processing methods is essential for the adoption of this technology. In order to understand, evaluate, and show these methods, it is a key to visualize their outputs. Several visualization tools exist, although it is usually difficult to find the suited one for a specific application. On the one hand, proprietary (closed source) projects are not flexible enough because they cannot be modified to adapt them to particular applications. On the other hand, current open source projects lack an effortless way to create custom visualizations. For these reasons, we present Olivia, a developer-friendly open source visualization tool for point clouds. Olivia provides the backbone for any type of point cloud visualization, and it can be easily extended and tailored to meet the requirements of a specific application. It supports stereoscopic 3-D view, aiding both the evaluation and presentation of processing methods. In this paper, several cases of study are presented to demonstrate the usefulness of Olivia along with its computational performance.S

Comunidad Internacional, Oriente Próximo y cultura de paz

Este número es el resultado del III Congreso de Cultura de Paz, titulado Comunidad Internacional, Oriente Próximo y cultura de paz, organizado por el Instituto de Estudios Internacionales y Europeos “Francisco de Vitoria” de la Universidad Carlos III de Madrid y UNESCO-Getafe, y celebrado en el Campus de Getafe de la Universidad Carlos III de Madrid los días 25, 26 y 27 de noviembre de 2013.Contiene: prólogo / Federico Mayor Zaragoza. -- Reflexiones sobre el uso de la fuerza y la protección internacional de los derechos humanos / Carlos Fernández Liesa. -- Sobre la responsabilidad de proteger (RP) y el uso legal de la fuerza (a propósito del conflicto en Siria [2011-2014]) / Cesáreo Gutiérrez Espada. -- Libre determinación de los pueblos y uso de la fuerza: MLNS, rebeldes, resistentes o terroristas / Félix Vacas Fernández. -- Armas de destrucción masiva en oriente próximo / Vicente Garrido Rebolledo. -- España ante el actual proceso de transformación política en el mundo árabe / Tomás López-Vilariño. -- Definiendo conceptos: Sufismo, Fundamentalismo, Salafismo, Islamismo y Wahabismo / Manuel González Hernández. -- Hacia una cultura de paz / Silvia Martínez Cantón

Tránsito en cuerda fija: su utilización en ámbitos educativos

El grupo de Investigación en Educación Física y Andinismo ha sido constituido en el Centro Regional Universitario Bariloche de la Universidad Nacional del Comahue como consecuencia de los estudios que en el marco de la carrera Profesorado en Educación Física (PEF) y de su orientación en actividades regionales de montaña, están siendo realizados. El objeto de esta comunicación se inscribe en la línea de trabajo que se comenzó a desarrollar en el año 2010 y a la que hemos denominado: Análisis de las prácticas de andinismo en ámbitos educativos. (Goicoechea Gaona, Palacio, 2014) En esta ocasión se trata de conceptualizar la práctica de tránsito por cuerda fija propia de la escalada. La misma forma parte de los contenidos de las asignaturas de formación docente del PEF Deportes Regionales Estivales I y II (DREI y II). Siguiendo la metodología de trabajo del grupo, se determinarán los aspectos específicos que hacen de dicha práctica un contenido de la Educación Física, es decir, resulta apropiada para ser enseñada y realizada en el ámbito educativo. De este modo damos continuidad a la tarea de sistematización de nuevas prácticas que por estar apareciendo en el contexto escolar requiere del estudio y tratamiento de especialistas en andinismo y educación.Mesa de trabajo 3: Educación física e investigaciónFacultad de Humanidades y Ciencias de la Educació

Saberes del montañismo y su articulación con la Educación Física en edades tempranas

Fil: Galosi, Carlos. Asistente de Docencia, Actividades en el Entorno Regional, Universidad Nacional del Comahue. Centro Regional Universitario Bariloche.Fil: Vilariño, Tomás. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche

Saberes del montañismo y su articulación con la Educación Física en edades tempranas

Fil: Galosi, Carlos. Asistente de Docencia, Actividades en el Entorno Regional, Universidad Nacional del Comahue. Centro Regional Universitario Bariloche.Fil: Vilariño, Tomás. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche

Saberes del montañismo y su articulación con la Educación Física en edades tempranas

Fil: Galosi, Carlos. Asistente de Docencia, Actividades en el Entorno Regional, Universidad Nacional del Comahue. Centro Regional Universitario Bariloche.Fil: Vilariño, Tomás. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche

Reflexiones sobre la evaluación de las prácticas de andinismo del Profesorado de Educación Física del Centro Regional Universitario Bariloche.

El presente trabajo se encuentra enmarcado en el Proyecto de Investigación: “Prácticas de Andinismo y Educación Física: los problemas de su enseñanza”, del Centro Regional Universitario Bariloche (Universidad Nacional del Comahue) dirigido por el Mg. Carlos Carballo y codirigido por el Prof. Eduardo López.Se presenta un análisis de la experiencia registrada a lo largo de 21 años de desarrollo del Profesorado en Educación Física, sobre las modalidades de evaluación implementadas en las asignaturas que conforman la Orientación “Actividades de Montañismo y Escalada”.El análisis se efectúa a partir de la articulación de los contenidos, las prácticas evaluativas y las incumbencias específicas de la orientación mencionada.Dado que este profesorado es el único en Educación Física de nuestro país con especialización en montaña, se reflejan las dificultades de establecer las bases de la evaluación sobre una temática de escaso desarrollo en el campo académico