Visual 3-D SLAM from UAVs

The aim of the paper is to present, test and discuss the implementation of Visual SLAM techniques to images taken from Unmanned Aerial Vehicles (UAVs) outdoors, in partially structured environments. Every issue of the whole process is discussed in order to obtain more accurate localization and mapping from UAVs flights. Firstly, the issues related to the visual features of objects in the scene, their distance to the UAV, and the related image acquisition system and their calibration are evaluated for improving the whole process. Other important, considered issues are related to the image processing techniques, such as interest point detection, the matching procedure and the scaling factor. The whole system has been tested using the COLIBRI mini UAV in partially structured environments. The results that have been obtained for localization, tested against the GPS information of the flights, show that Visual SLAM delivers reliable localization and mapping that makes it suitable for some outdoors applications when flying UAVs

On-board and Ground Visual Pose Estimation Techniques for UAV Control

In this paper, two techniques to control UAVs (Unmanned Aerial Vehicles), based on visual information are presented. The first one is based on the detection and tracking of planar structures from an on-board camera, while the second one is based on the detection and 3D reconstruction of the position of the UAV based on an external camera system. Both strategies are tested with a VTOL (Vertical take-off and landing) UAV, and results show good behavior of the visual systems (precision in the estimation and frame rate) when estimating the helicopter¿s position and using the extracted information to control the UAV

Omnidirectional vision applied to Unmanned Aerial Vehicles (UAVs) attitude and heading estimation

11 páginas, 14 figuras, 3 tablas.-- El Pdf del artículo es la versión pre-print.This paper presents an aircraft attitude and heading estimator using catadioptric images as a principal sensor for UAV or as a redundant system for IMU (Inertial Measure Unit) and gyro sensors. First, we explain how the unified theory for central catadioptric cameras is used for attitude and heading estimation, explaining how the skyline is projected on the catadioptric image and how it is segmented and used to calculate the UAV’s attitude. Then, we use appearance images to obtain a visual compass, and we calculate the relative rotation and heading of the aerial vehicle. Finally the tests and results using the UAV COLIBRI platform and the validation of them in real flights are presented, comparing the estimated data with the inertial values measured on board.The authors would like to thank Jorge Leon for supporting the flight trials, the I.A. Institute-CSIC for collaborating in the flights, and the Universidad Politécnica de Madrid, and Consejería de Educación de la Comunidad de Madrid and the Fondo Social Europeo (FSE) for the authors' Ph.D. funding. This work has been sponsored by the Spanish Science Technology Ministry under the Grant CICYT DPI 2007-66156.Peer reviewe

Inspección no invasiva de Physalis peruviana usando técnicas (Vir/Nir)

This article describes the development of a flexible architecture that allows the classification of fruit Physalis peruviana (gooseberries) using a computer vision system based on space images in the Visible and near infrared (VIS / NIR) arises. To develop a model that provides quality control for the marketing and export of fruit in Colombia, “Uchuva”. The solution consists of a system of real-time classification of fruit, implementing technologies for industrial automation and process visible and infrared images of the space. To validate an analysis proposed by the correlation between technologies in the field of artificial vision with their profits in the automation of processes against traditional methods in the quality inspection of fruit. By last development of a model which implements a classification algorithm associating a direct impact on costs during the current process present.Este artículo plantea el desarrollo de una arquitectura flexible que permite la clasificación de la fruta Physalis peruviana (uchuvas) empleando un sistema de visión por computador, basado en imágenes en el espacio Visible e Infrarrojo cercano (VIS/NIR). Para el desarrollo se establece un modelo que facilita el control de calidad para la comercialización y exportación de la fruta en Colombia, la Uchuva. La solución consiste de un sistema de clasificación en tiempo real de la fruta, implementando tecnologías de automatización industrial y procesamiento de imágenes del espacio visible e infrarojo. Para la validación se propone un análisis mediante la correlación entre tecnologías en el campo de visión artificial con sus beneficios en la automatización de procesos, contra métodos tradicionales en la inspección de calidad de la fruta. Por último se presenta el desarrollo de un modelo el cual implementa un algoritmo de clasificación asociando un impacto directo en los costos correspondientes al proceso actual

A general purpose configurable controller for indoors and outdoors GPS-Denied navigation for multirotor unmanned aerial vehicles

This research on odometry based GPS-denied navigation on multirotor Unmanned Aerial Vehicles is focused among the interactions between the odometry sensors and the navigation controller. More precisely, we present a controller architecture that allows to specify a speed specified flight envelope where the quality of the odometry measurements is guaranteed. The controller utilizes a simple point mass kinematic model, described by a set of configurable parameters, to generate a complying speed plan. For experimental testing, we have used down-facing camera optical-flow as odometry measurement. This work is a continuation of prior research to outdoors environments using an AR Drone 2.0 vehicle, as it provides reliable optical flow on a wide range of flying conditions and floor textures. Our experiments show that the architecture is realiable for outdoors flight on altitudes lower than 9 m. A prior version of our code was utilized to compete in the International Micro Air Vehicle Conference and Flight Competition IMAV 2012. The code will be released as an open-source ROS stack hosted on GitHub.This work was supported by the Spanish Science and Technology Ministry under the grant CICYT DPI2010-20751-C02-01, and the following institutions by their scholarship grants: CSIC-JAE, CAM and the Chinese Scholarship Council. All the authors are with the Computer Vision Group, www.vision4uav.eu, which belongs to the Centre for Automation and Robotics, joint research center from the Spanish National Research Council (CSIC) and the Polytechnic University of Madrid (UPM).Peer Reviewe

An approach toward visual autonomous ship board landing of a VTOL UAV

We present the design and implementation of a vision based autonomous landing algorithm using a downward looking camera. To demonstrate the efficacy of our algorithms we emulate the dynamics of the ship-deck, for various sea states and different ships using a six degrees of freedom motion platform. We then present the design and implementation of our robust computer vision system to measure the pose of the shipdeck with respect to the vehicle. A Kalman filter is used in conjunction with our vision system to ensure the robustness of the estimates. We demonstrate the accuracy and robustness of our system to occlusions, variation in intensity, etc. using our testbed. © 2013 Springer Science+Business Media Dordrecht.Consejo Superior de Investigaciones Cientificas (CSIC) of SpainUECMUAVS Project PIRSES-GASpanish Ministry of Science MICYT. DPI2010-20751-C02-01Peer Reviewe

An Immersive Virtual Reality Training Game for Power Substations Evaluated in Terms of Usability and Engagement

Safety-focused training is essential for the operation and maintenance concentrated on the reliability of critical infrastructures, such as power grids. This paper introduces and evaluates a system for power substation operational training by exploring and interacting with realistic models in virtual worlds using serious games. The virtual reality (VR) simulator used building information modelling (BIM) from a 115 kV substation to develop a scenario with high technical detail suitable for professional training. This system created interactive models that could be explored using a first-person-perspective serious game in a cave automatic virtual environment (CAVE). Different operational missions could be carried out in the serious game, allowing several skills to be coached. The suitability for vocational training carried out by utility companies was evaluated in terms of usability and engagement. The evaluation used a System Usability Scale (SUS) and a Game Engagement Questionnaire (GEQ) filled by 16 power substation operators demonstrating marginally acceptable usability, with improvement opportunities and high acceptance (by utility technicians) of this system for operation training focused on safety in such hazardous tasks

An Immersive Virtual Reality Training Game for Power Substations Evaluated in Terms of Usability and Engagement

Safety-focused training is essential for the operation and maintenance concentrated on the reliability of critical infrastructures, such as power grids. This paper introduces and evaluates a system for power substation operational training by exploring and interacting with realistic models in virtual worlds using serious games. The virtual reality (VR) simulator used building information modelling (BIM) from a 115 kV substation to develop a scenario with high technical detail suitable for professional training. This system created interactive models that could be explored using a first-person-perspective serious game in a cave automatic virtual environment (CAVE). Different operational missions could be carried out in the serious game, allowing several skills to be coached. The suitability for vocational training carried out by utility companies was evaluated in terms of usability and engagement. The evaluation used a System Usability Scale (SUS) and a Game Engagement Questionnaire (GEQ) filled by 16 power substation operators demonstrating marginally acceptable usability, with improvement opportunities and high acceptance (by utility technicians) of this system for operation training focused on safety in such hazardous tasks

Unmanned aerial vehicles UAVs attitude, height, motion estimation and control using visual systems

This paper presents an implementation of an aircraft pose and motion estimator using visual systems as the principal sensor for controlling an Unmanned Aerial Vehicle (UAV) or as a redundant system for an Inertial Measure Unit (IMU) and gyros sensors. First, we explore the applications of the unified theory for central catadioptric cameras for attitude and heading estimation, explaining how the skyline is projected on the catadioptric image and how it is segmented and used to calculate the UAV’s attitude. Then we use appearance images to obtain a visual compass, and we calculate the relative rotation and heading of the aerial vehicle. Additionally, we show the use of a stereo system to calculate the aircraft height and to measure the UAV’s motion. Finally, we present a visual tracking system based on Fuzzy controllers working in both a UAV and a camera pan and tilt platform. Every part is tested using the UAV COLIBRI platform to validate the different approaches, which include comparison of the estimated data with the inertial values measured onboard the helicopter platform and the validation of the tracking schemes on real flights