Estimating the motion of an underwater robot from a monocular image sequence

When underwater vehicles perform navigation close to the ocean floor, computer vision techniques can be applied to obtain quite accurate motion estimates. The most crucial step in the vision-based estimation of the vehicle motion consists on detecting matchings between image pairs. Here we propose the extensive use of texture analysis as a tool to ameliorate the correspondence problem in underwater images. Once a robust set of correspondences has been found, the three-dimensional motion of the vehicle can be computed with respect to the bed of the sea. Finally, motion estimates allow the construction of a map that could aid to the navigation of the robot

Towards a real-time vision-based navigation system for a small-class UUV

This paper deals with the problem of navigation for an unmanned underwater vehicle (UUV) through image mosaicking. It represents a first step towards a real-time vision-based navigation system for a small-class low-cost UUV. We propose a navigation system composed by: (i) an image mosaicking module which provides velocity estimates; and (ii) an extended Kalman filter based on the hydrodynamic equation of motion, previously identified for this particular UUV. The obtained system is able to estimate the position and velocity of the robot. Moreover, it is able to deal with visual occlusions that usually appear when the sea bottom does not have enough visual features to solve the correspondence problem in a certain area of the trajectory

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

PRIM an Open Mobile Robot Platform. Motivation, Present and Future Trends

This paper is focused on the robot mobile platform PRIM (platform robot information multimedia). This robot has been made in order to cover two main needs of our group, on one hand the need for a full open mobile robotic platform that is very useful in fulfilling the teaching and research activity of our school community, and on the other hand with the idea of introducing an ethical product which would be useful as mobile multimedia information point as a service tool. This paper introduces exactly how the system is made up and explains just what the philosophy is behind this work. The navigation strategies and sensor fusion, where machine vision system is the most important one, are oriented towards goal achievement and are the key to the behaviour of the robot

Knowledge integration within an applied mobile robot summer course

This paper presents the use of a mobile robot platform as an innovative educational tool in order to promote and integrate different curriculum knowledge. Hence, it is presented the acquired experience within a summer course named ldquoapplied mobile roboticsrdquo. The main aim of the course is to integrate different subjects as electronics, programming, architecture, perception systems, communications, control and trajectory planning by using the educational open mobile robot platform PRIM. The summer course is addressed to a wide range of student profiles. However, it is of special interests to the students of electrical and computer engineering around their final academic year. The summer course consists of the theoretical and laboratory sessions, related to the following topics: design & programming of electronic devices, modelling and control systems, trajectory planning and control, and computer vision systems. Therefore, the clues for achieving a renewed path of progress in robotics are the integration of several knowledgeable fields, such as computing, communications, and control sciences, in order to perform a higher level reasoning and use decision tools with strong theoretical base

A Camera-Projector System for Robot Positioning by Visual Servoing

Positioning a robot with respect to objects by using data provided by a camera is a well known technique called visual servoing. In order to perform a task, the object must exhibit visual features which can be extracted from different points of view. Then, visual servoing is object-dependent as it depends on the object appearance. Therefore, performing the positioning task is not possible in presence of nontextured objets or objets for which extracting visual features is too complex or too costly. This paper proposes a solution to tackle this limitation inherent to the current visual servoing techniques. Our proposal is based on the coded structured light approach as a reliable and fast way to solve the correspondence problem. In this case, a coded light pattern is projected providing robust visual features independently of the object appearance

Entorn de programació pel robot Stäubli mitjantçant MatLab, aplicació a un sistema de recol·lecció de peces basat en visió artificial

Els objectius del projecte són: realitzar un intèrpret de comandes en VAL3 que rebi les ordres a través d’una connexió TCP/IP; realitzar una toolbox de Matlab per enviar diferents ordres mitjançant una connexió TCP/IP; adquirir i processar mitjançant Matlab imatges de la càmera en temps real i detectar la posició d’objectes artificials mitjançant la segmentació per color i dissenyar i realitzar una aplicació amb Matlab que reculli peces detectades amb la càmera. L’abast del projecte inclou: l’estudi del llenguatge de programació VAL3 i disseny de l’ intèrpret de comandes, l’estudi de les llibreries de Matlab per comunicació mitjançant TCP/IP, per l’adquisició d’imatges, pel processament d’imatges i per la programació en C; el disseny de la aplicació recol·lectora de peces i la implementació de: un intèrpret de comandes en VAL3, la toolbox pel control del robot STAUBLI en Matlab i la aplicació recol·lectora de peces mitjançant el processament d’imatges en temps real també en Matlab

Mobile Robot Local Predictive Control under Perception Constraints

This research extends a previously developed work concerning about the use of local model predictive control in mobile robots. Hence, experimental results are presented as a way to improve the methodology by considering aspects as trajectory accuracy and time performance. In this sense, the cost function and the prediction horizon are important aspects to be considered. The platformused is a differential driven robot with a free rotating wheel. The aim of the present work is to test the control method by measuring trajectory tracking accuracy and time performance. Moreover, strategies for the integration with perception system and path planning are also introduced. In this sense, monocular image data provide an occupancy grid where safety trajectories are computed by using goal attraction potential fields

Efficient image mosaicing for multi-robot visual underwater mapping

Robotic platforms have advanced greatly in terms of their remote sensing capabilities, including obtaining optical information using cameras. Alongside these advances, visual mapping has become a very active research area, which facilitates the mapping of areas inaccessible to humans. This requires the efficient processing of data to increase the final mosaic quality and computational efficiency. In this paper, we propose an efficient image mosaicing algorithm for large area visual mapping in underwater environments using multiple underwater robots. Our method identifies overlapping image pairs in the trajectories carried out by the different robots during the topology estimation process, being this a cornerstone for efficiently mapping large areas of the seafloor. We present comparative results based on challenging real underwater datasets, which simulated multi-robot mapping

Control remoto (web) de un robot Aibo

El robot Aibo disposa de la llibreria Aibo Remote Framework per controlar-lo remotament mitjançant un PC i una xarxa inalàmbrica, també per accedir a informació d'estat del robot, o per veure les imatges que l'Aibo capta. Combinant Remote Framework i php s'ha creat una aplicació web que permet controlar Aibos diferents remotament per Internet, així com tenir accés a les imatges subjectives de cadascun dels Aibos. A més, la tecnologia existent d'streaming permet que l'aplicació web tingui un vídeo incrustat que possibilita veure en directe els Aibos mitjançant una càmera web enfocada cap a ells.

Programación de un robot autónomo: diseño, construcción, programación e integración de un robot autónomo en el entorno Pyro

En aquest projecte, s'ha dissenyat, construït i programat un robot autònom, dotat de sistema de locomoció i sensors que li permeten navegar sense impactar en un entorn controlat. Per assolir aquests objectius s'ha dissenyat i programat una unitat de control que gestiona el hardware de baix volum de dades amb diferents modes d'operació, abstraient-lo en una única interfície. Posteriorment s'ha integrat aquest sistema en l'entorn de robòtica Pyro. Aquest entorn permet usar i adaptar, segons es necessiti, eines d'intel·ligència artificial ja desenvolupades.

Robot educatiu per un PBL en enginyeria informàtica

En aquest projecte s’ha estudiat el disseny d’una plataforma robòtica mòbil per un PBL (Aprenentatge Basat en Problemes) en enginyeria informàtica. El principal objectiu és introduir aquest model en l’ensenyament universitari, com a complement de diferents assignatures de primer curs. Per arribar a aconseguir aquests objectius, s’ha dissenyat i construït una plataforma robòtica, dirigida per un microcontrolador i dotada de diversos sensors per interactuar amb l’entorn. El robot permet diferents tipus de programació i esta especialment dissenyada per ser una bona experiència educativa.

Object recognition for autonomous objects: comparison of two approaches

Report for the scientific sojourn at the Swiss Federal Institute of Technology Zurich, Switzerland, between September and December 2007. In order to make robots useful assistants for our everyday life, the ability to learn and recognize objects is of essential importance. However, object recognition in real scenes is one of the most challenging problems in computer vision, as it is necessary to deal with difficulties. Furthermore, in mobile robotics a new challenge is added to the list: computational complexity. In a dynamic world, information about the objects in the scene can become obsolete before it is ready to be used if the detection algorithm is not fast enough. Two recent object recognition techniques have achieved notable results: the constellation approach proposed by Lowe and the bag of words approach proposed by Nistér and Stewénius. The Lowe constellation approach is the one currently being used in the robot localization project of the COGNIRON project. This report is divided in two main sections. The first section is devoted to briefly review the currently used object recognition system, the Lowe approach, and bring to light the drawbacks found for object recognition in the context of indoor mobile robot navigation. Additionally the proposed improvements for the algorithm are described. In the second section the alternative bag of words method is reviewed, as well as several experiments conducted to evaluate its performance with our own object databases. Furthermore, some modifications to the original algorithm to make it suitable for object detection in unsegmented images are proposed.

NXT: el robot de Lego

Treball de recerca realitzat per un alumne d'ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit cientí­fic del Jovent l'any 2009. L'NXT és un robot creat per l'empresa Lego que disposa d'un controlador, de diversos servo motors i de sensors (tacte, llum, ultrasons, so...). Es programa mitjançant un programa especial, pensat per nois i noies de catorze anys, anomenat Lego Mindstorms. S'estudia el funcionament d'aquest programa i les parts del sistema de control del robot. L'estudi engloba el controlador, quatre sensors i els servomotors.

Interfaz de usuario de un sistema multi-robot de reconocimiento de superficies con Google Earth

Els sistemes multi-robot de reconeixement de superfícies es poden utilitzar tant per a l'exploració de llocs remots, de difícil accés o perillosos. Normalment, els robots no són autònoms, depenen d'operadors humans per dirigir-los. La informació que capten ha de ser processada i mostrada a l'usuari o usuària del sistema de forma intel·ligible. Un exemple d'aplicació seria el d'un sistema multirobot format per diversos helicòpters no tripulats que proporciona informació d'una àrea que ha patit algun desastre. El sistema informàtic recolliria la informació i la transmetria al coordinador de l'operatiu d'assistència de l'emergència. La idea del projecte és la de combinar la informació proporcionada pel sistema multi-robot amb la de la zona disponible a Google Earth i fer d'aquesta eina l'interfície d'usuari de l'aplicació.