Interest point detectors for visual SLAM

In this paper we present several interest points detectors and we analyze their suitability when used as landmark extractors for vision-based simultaneous localization and mapping (vSLAM). For this purpose, we evaluate the detectors according to their repeatability under changes in viewpoint and scale. These are the desired requirements for visual landmarks. Several experiments were carried out using sequence of images captured with high precision. The sequences represent planar objects as well as 3D scenes

Local descriptors for visual SLAM

We present a comparison of several local image descriptors in the context of visual Simultaneous Localization and Mapping (SLAM). In visual SLAM a set of points in the environment are extracted from images and used as landmarks. The points are represented by local descriptors used to resolve the association between landmarks. In this paper, we study the class separability of several descriptors under changes in viewpoint and scale. Several experiments were carried out using sequences of images in 2D and 3D scenes

A comparative evaluation of interest point detectors and local descriptors for visual SLAM

Abstract In this paper we compare the behavior of different interest points detectors and descriptors under the conditions needed to be used as landmarks in vision-based simultaneous localization and mapping (SLAM). We evaluate the repeatability of the detectors, as well as the invariance and distinctiveness of the descriptors, under different perceptual conditions using sequences of images representing planar objects as well as 3D scenes. We believe that this information will be useful when selecting an appropriat

A morphological approach to evaluating the nature of vineyard soils in semiarid Mediterranean environment

La Mancha (Central Spain) is one of the most extensive vineyard regions in the world, and ‘Valdepeñas’ is a representative Protected Denomination of Origin (PDO) in this region. However, what are their main soil types? what kind of horizons are the most common? and what is the role of the geomorphological positions in their pedodiversity? After describing and sampling 90 soil profiles in this area, Alfisols, Inceptisols and Entisols were mainly identified in Soil Taxonomy terms; in other words, Luvisols, Cambisols, Regosols, Leptosols and a highly significant proportion of Calcisols according to FAO-UNESCO-ISSS. The accumulation of carbonate, the thickness of which varies from a diffuse or powdery form to crusted forms, appear sometimes like polycyclic. The presence of red soils, with or without a calcic or petrocalcic horizon, indicates the most representative edaphic stages in this region. Consequently, the morphological signature is calcic or petrocalcic, followed by argillic and/or cambic horizons, under ochric horizons. It can be concluded that the nature of soils in Valdepeñas can be considered a differential factor to bear in mind for quality viticultural production. Highlights: There are unknown conceptual zones in support production of wine. A comprehensive study in a local case was performed due to its traditional production of vineyards. This study highlights the importance and uniqueness of the calcic and petrocalcic horizons. A disconnect exists between some tradicional viticultural zones with low reputation and the real value of their soil

Planificación simultánea de trayectoria y contactos de un robot caminante

En este artículo estudiamos la planificación simultánea de la trayectoria y de los apoyos de las patas de un robot en terrenos irregulares. Partimos del algoritmo A estrella (A*), que busca el camino más corto entre dos puntos. Primero se modela el terreno con un mallado triangular y se subdividen los triángulos, para tomar como espacio de búsqueda del A* los centroides de dichos triángulos. En segundo lugar, con respecto al A* original, se ha considerado la estabilidad del robot en cada centroide, de modo que el coste en un centroide sea penalizado si el robot es inestable y nulo si es estable. La estabilidad en cada punto de contacto se determina calculando que la reacción del terreno en ese punto esté contenida en un cono de fricción con una aproximación lineal. Por último, se obtiene la trayectoria, los puntos de contacto de cada pata, así como la postura del robot en cada posició

Estimación de zonas transitables en nubes de puntos 3D con redes convolucionales dispersas

La correcta evaluación del entorno en tareas como la navegación de robots terrestres o la conducción autónoma de vehículos se debe considerar un requisito mínimo para dotar de independencia a un sistema robótico. En concreto, la navegación de un robot en entornos desconocidos, naturales y desestructurados precisa contar con técnicas que permitan seleccionar sobre qué zonas puede circular el robot. Con el fin de poder aumentar la soberanía de las decisiones autónomas del sistema, en este artículo se propone un método para la evaluación de las nubes de puntos 3D obtenidas mediante un LiDAR con objeto de obtener las zonas transitables, tanto en entornos de carretera como en entornos naturales. Concretamente, se propone una configuración codificador-decodificador dispersa entrenada con características invariantes a rotación, que tiene como fin replicar los datos de entrada asociando a cada punto las características e transitabilidad aprendidas. Los resultados experimentales muestran la robustez y efectividad del método propuesto en entornos de exteriores, llegando a mejorar los resultados de otros enfoques

An environmental approach to understanding the expansion of future vineyards: Case study of soil developed on alluvial sediments

The importance of soil properties in wine grape production is generally treated as secondary to climate and canopy management. This study was undertaken to characterize and classify a singular soil resource for a vineyard in a traditional viticultural region: Castilla-La Mancha, central Spain. The soil under study was described and sampled using standard soil survey procedures as outlined by FAO, and served as a pedologic window for Gleyic Fluvisol (Calcaric, Humic), according to the FAO System, or Fluventic Haploxerept, according to the Soil Taxonomy System. This soil, developed on alluvial materials of Holocene age related to the Gigüela river (either carbonatic or gypsiferous) has, in addition to obvious hydromorphic features (that reduce its use), high organic matter content (5.5% in the Ap horizon) and moderate salt content (between 1.14 and 2.39 dS/m). Other properties are common to most vineyard soils in Castilla-La Mancha, such as alkaline reactivity (pH between 7.6 and 8.2); calcium and magnesium as the dominant cations followed by sodium and potassium; finally, some deficiency in N (0.11%) and P (12.3 mg/kg). The most restricting soil factors for vineyard growth of this soil type were waterlogging, which can affect vine roots, and the appearance of certain salinity problems. The final conclusion of this study was that the use of the studied soil type for vineyard cultivation could be recommended to farmers only in the case of improving soil properties—for example, draining the river level