Autonomous underwater vehicle control using reinforcement learning policy search methods

Autonomous underwater vehicles (AUV) represent a challenging control problem with complex, noisy, dynamics. Nowadays, not only the continuous scientific advances in underwater robotics but the increasing number of subsea missions and its complexity ask for an automatization of submarine processes. This paper proposes a high-level control system for solving the action selection problem of an autonomous robot. The system is characterized by the use of reinforcement learning direct policy search methods (RLDPS) for learning the internal state/action mapping of some behaviors. We demonstrate its feasibility with simulated experiments using the model of our underwater robot URIS in a target following task

Large-Area Photo-Mosaics Using Global Alignment and Navigation Data

Seafloor imagery is a rich source of data for the study of biological and geological processes. Among several applications, still images of the ocean floor can be used to build image composites referred to as photo-mosaics. Photo-mosaics provide a wide-area visual representation of the benthos, and enable applications as diverse as geological surveys, mapping and detection of temporal changes in the morphology of biodiversity. We present an approach for creating globally aligned photo-mosaics using 3D position estimates provided by navigation sensors available in deep water surveys. Without image registration, such navigation data does not provide enough accuracy to produce useful composite images. Results from a challenging data set of the Lucky Strike vent field at the Mid Atlantic Ridge are reported

Laser stripe peak detector for 3D scanners: a FIR filter approach

The accuracy of a 3D reconstruction using laser scanners is significantly determined by the detection of the laser stripe. Since the energy pattern of such a stripe corresponds to a Gaussian profile, it makes sense to detect the point of maximum light intensity (or peak) by computing the zero-crossing point of the first derivative of such Gaussian profile. However, because noise is present in every physical process, such as electronic image formation, it is not sensitive to perform the derivative of the image of the stripe in almost any situation, unless a previous filtering stage is done. Considering that stripe scanning is an inherently row-parallel process, every row of a given image must be processed independently in order to compute its corresponding peak position in the row. This paper reports on the use of digital filtering techniques in order to cope with the scanning of different surfaces with different optical properties and different noise levels, leading to the proposal of a more accurate numerical peak detector, even at very low signal-to-noise ratios

Model-based objects recognition in industrial environments for autonomous vehicles control

Behavior-based navigation of autonomous vehicles requires the recognition of the navigable areas and the potential obstacles. In this paper we describe a model-based objects recognition system which is part of an image interpretation system intended to assist the navigation of autonomous vehicles that operate in industrial environments. The recognition system integrates color, shape and texture information together with the location of the vanishing point. The recognition process starts from some prior scene knowledge, that is, a generic model of the expected scene and the potential objects. The recognition system constitutes an approach where different low-level vision techniques extract a multitude of image descriptors which are then analyzed using a rule-based reasoning system to interpret the image content. This system has been implemented using a rule-based cooperative expert system

Accuracy estimation of a new omnidirectional 3D vision sensor

We present a computer vision system that associates omnidirectional vision with structured light with the aim of obtaining depth information for a 360 degrees field of view. The approach proposed in this article combines an omnidirectional camera with a panoramic laser projector. The article shows how the sensor is modelled and its accuracy is proved by means of experimental results. The proposed sensor provides useful information for robot navigation applications, pipe inspection, 3D scene modelling etc

Overview of coded light projection techniques for automatic 3D profiling

Obtaining automatic 3D profile of objects is one of the most important issues in computer vision. With this information, a large number of applications become feasible: from visual inspection of industrial parts to 3D reconstruction of the environment for mobile robots. In order to achieve 3D data, range finders can be used. Coded structured light approach is one of the most widely used techniques to retrieve 3D information of an unknown surface. An overview of the existing techniques as well as a new classification of patterns for structured light sensors is presented. This kind of systems belong to the group of active triangulation method, which are based on projecting a light pattern and imaging the illuminated scene from one or more points of view. Since the patterns are coded, correspondences between points of the image(s) and points of the projected pattern can be easily found. Once correspondences are found, a classical triangulation strategy between camera(s) and projector device leads to the reconstruction of the surface. Advantages and constraints of the different patterns are discussed

Implementation of a robust coded structured light technique for dynamic 3D measurements

This paper presents the implementation details of a coded structured light system for rapid shape acquisition of unknown surfaces. Such techniques are based on the projection of patterns onto a measuring surface and grabbing images of every projection with a camera. Analyzing the pattern deformations that appear in the images, 3D information of the surface can be calculated. The implemented technique projects a unique pattern so that it can be used to measure moving surfaces. The structure of the pattern is a grid where the color of the slits are selected using a De Bruijn sequence. Moreover, since both axis of the pattern are coded, the cross points of the grid have two codewords (which permits to reconstruct them very precisely), while pixels belonging to horizontal and vertical slits have also a codeword. Different sets of colors are used for horizontal and vertical slits, so the resulting pattern is invariant to rotation. Therefore, the alignment constraint between camera and projector considered by a lot of authors is not necessary

Using petri nets to specify and execute missions for autonomous underwater vehicles

This paper presents the design and implementation of a mission control system (MCS) for an autonomous underwater vehicle (AUV) based on Petri nets. In the proposed approach the Petri nets are used to specify as well as to execute the desired autonomous vehicle mission. The mission is easily described using an imperative programming language called mission control language (MCL) that formally describes the mission execution thread. A mission control language compiler (MCL-C) able to automatically translate the MCL into a Petri net is described and a real-time Petri net player that allows to execute the resulting Petri net onboard an AUV are also presented

Social Networking Sites as Technology Enhanced Learning Communities towards autonomous language learning

The following contribution pretends to cope with the demands of a globalised, post-modern environment through the design and implementation of an online international project where an SNS is used in order to join English as Second Language (ESL) students from different parts of the world. The design of the project appears around the implementation of the Bologna process in the Faculty of Education from the University of Girona where the basic prerequisite of all students to acquire English at the level B1 of the Common European Portfolio makes English a compulsory competence for communication among its higher education candidates in order to develop in the world. Together with the University of Girona, there is the International Educational and Resources Network (iEARN) which promotes the participation of schools around the world in online international projects

Didactics–promoting collaborative work and personal learning environment. Critical, creative and autonomous roles in a competitive society

School has evolved from a place where knowledge is provided to a place where learners are helped to develop their professional and social skills. Consequently, education must evolve through big challenges in order to face the changes of society in the XXIst century

Visualización avanzada en globos 3D

Durante los últimos meses IGO Software ha estado desarrollando activamente el proyecto glob3, la librería euclid y junto a la Universidad de Extremadura la migración de la librería sextante a un entorno 3D. Todas estas tareas han concluido en la liberación de un Framework para el desarrollo de aplicaciones 3D denominado glob3 que seguirá desarrollándose al menos durante todo el 2011 y cuyo roadmap puede ser consultado en la página del proyecto http://www.glob3.org. En este marco se han desarrollado varias formas avanzadas de visualización de información georeferenciada que pensamos pueden ser interesantes para la comunidad ya que no han sido desarrolladas anteriormente en software libre, concretamente presentaremos: • Visualización de nubes de puntos mediante streaming • Visualización de modelos 3D • Visualización de archivos multidimensionales en formatos netCDF (network Common Data Form) • Visualizacion de archivos GIS vectoriales • Gigaimágenes y fotos 360º

Visualización geográfica 3D mediante un API Universal y políglota. Acercando los globos virtuales al desarrollador de mashups de mapas

La librería Javascript de código abierto Mapstraction permite al desarrollador abstraerse de las pequeñas diferencias entre las distintas APIs de mapas. Mediante el uso de esta librería, el creador de mashups de mapas puede implementar sus aplicaciones tan sólo una vez con la posibilidad de cambiar de proveedor de mapas de forma sencilla, si así se requiere. En el presente trabajo se ha extendido la funcionalidad de esta librería para el soporte de funcionalidad 3D propia de los globos virtuales, de la que hasta ahora carecía: selección del ángulo de visión, extrusión del terreno, estereoscopía 3D o inclusión de modelos tridimensionales, por citar algunas. Además, se ha realizado una integración del globo virtual de la Nasa, de código abierto, World Wind, antes apenas utilizado para el desarrollo de mashups al no disponer de un API Javascript para su fácil incorporación

Integración de los estándares OGC en los clientes 2D y 3D de visualización de mapas

A través de la propuesta Styled Layer Descriptor 3D (SLD3D), cuya especificación se encuentra en el Open Geospatial Consortium (OGC), se posibilitará la generación de información tridimensional. La interpretación de estos estilos a través del Keyhole Markup Language (KML) y su representación en los interfaces 3D, garantizarán el aprovechamiento de la tercera componente espacial permitiendo una representación realista del entorno

Dielmo 3D Viewer based on NASA World Wind

Partiendo de la versión Java del software libre NASA World Wind, DIELMO ha desarrollado el software Dielmo 3D Viewer que permite la creación de escenarios virutales en 3D que se convierten en clientes IDE y que permiten un mejor conocimiento del territorio, tratando la tercera dimensión con el máximo rigor

Desarrollo personalizado de aplicaciones SIG 3D

En los últimos años la proliferación de aplicaciones 3D en SIG ha sido enorme, desde la aparición de Google Earth el usuario está familiarizado con entornos 3D. Por otra parte lo ordenadores con aceleración 3D son comunes en la actualidad y el acceso a banda ancha es prácticamente generalizado, además cada vez hay mayor cantidad de datos públicos que pueden ser utilizados por clientes SIG que sean capas de recibir datos de Internet.Hay varias librerías apropiadas para la realización de este tipo de aplicaciones. IGO SOFTWARE a comenzado a desarrollar aplicaciones 3D con las librería Nasa World Wind SDK para java.Decidimos usar estar librerías por su robustez, sencillez, cantidad de ejemplo, estar hechas en java (nos permite su unión a muchas librerías SIG) y su uso de caché local. Las aplicaciones desarrolladas en 3D no sólo son visualmente más atractivas, también nos ofrecen más información que el SIG clásico en 2D. Gracias a la integración de librerías como SEXTANTE ahora es posible también realizar análisis. En un futuro se espera poder desarrollar también algoritmos de análisis en 3D usando dicha plataforma. Por otra parte, llevamos desde hace algunos años desarrollando aplicaciones para el tratamiento de nubes de puntos proveniente de Láser Escáner y LIDAR, esta plataforma es ideal para mostrar nubes de puntos, por lo que es perfecta para visualizar nubes de puntos georreferenciadas. Mostraremos ejemplos de aplicaciones programadas con estas librerías y las posibilidades que vemos de cara a un futuro a este tipo de desarrollos