Omnidirectional underwater surveying and telepresence

Exploratory dives are traditionally the first step for marine scientists to acquire information on a previously unknown area of scientific interest. Manned submersibles have been the platform of choice for such exploration, as they allow a high level of environmental perception by the scientist on-board, and the ability to take informed decisions on what to explore next. However, manned submersibles have extremely high operation costs and provide very limited bottom time. Remotely operated vehicles (ROVs) can partially address these two issues, but have operational and cost constraints that restrict their usage. This paper discusses new capabilities to assist scientists operating lightweight hybrid remotely operated vehicles (HROV) in exploratory missions of mapping and surveying. The new capabilities, under development within the Spanish National project OMNIUS, provide a new layer of autonomy for HROVs by exploring three key concepts: Omni-directional optical sensing for collaborative immersive exploration, Proximity safety awareness and Online mapping during mission time.Peer Reviewe

Underwater navigation and mapping with an omnidirecional optical sensor

Omnidirectional vision has received increasing interest during the last decade from the computer vision community. However, the use of omnidirectional cameras underwater is still very limited. In this thesis we propose several methods to create a reference resource for designing, calibrating and using underwater omnidirectional multi-camera systems (OMS). The first problem we address is their design and calibration. Next, we study stitching strategies to generate omnidirectional panoramas from individual images. Finally, we focus on potential underwater applications. We first explore the promising uses of omnidirectional cameras to create immersive virtual experiences and secondly, we demonstrate the capabilities of omnidirectional cameras as complementary sensors for the navigation of underwater robots. To validate all presented algorithms, two custom omnidirectional cameras were built and several experiments with divers and underwater robots have been carried out to collect the necessary data.Durant l'última dècada s'ha despertat un interès creixent per a la visió omnidireccional en l'àmbit de la visió per computador. Tot i això, l'ús de càmeres omnidireccionals submarines encara és molt limitat. En aquesta tesi doctoral hem creat un recurs de referència per al disseny, calibratge i ús de càmeres omnidireccionals submarines de tipus multi-càmera. El primer problema que tractem és el seu disseny i calibratge. Després ens centrem en l'estudi d’estratègies de combinació d'imatges per tal de generar imatges panoràmiques partint de múltiples imatges capturades per diferents càmeres. Finalment, ens centrem en les aplicacions potencials de les càmeres omnidireccionals submarines. Primer, explorem els prometedors usos de les càmeres per tal de crear experiències virtuals immersives. Després, demostrem les capacitats de les càmeres omnidireccionals com a sensors complementaris per a la navegació de robots. Per tal de validar tots els algoritmes presentats s'han dissenyat dues càmeres omnidireccionals i s'han realitzat múltiples experiments

Omnidirectional Underwater Camera Design and Calibration

This paper presents the development of an underwater omnidirectional multi-camera system (OMS) based on a commercially available six-camera system, originally designed for land applications. A full calibration method is presented for the estimation of both the intrinsic and extrinsic parameters, which is able to cope with wide-angle lenses and non-overlapping cameras simultaneously. This method is valid for any OMS in both land or water applications. For underwater use, a customized housing is required, which often leads to strong image distortion due to refraction among the different media. This phenomena makes the basic pinhole camera model invalid for underwater cameras, especially when using wide-angle lenses, and requires the explicit modeling of the individual optical rays. To address this problem, a ray tracing approach has been adopted to create a field-of-view (FOV) simulator for underwater cameras. The simulator allows for the testing of different housing geometries and optics for the cameras to ensure a complete hemisphere coverage in underwater operation. This paper describes the design and testing of a compact custom housing for a commercial off-the-shelf OMS camera (Ladybug 3) and presents the first results of its use. A proposed three-stage calibration process allows for the estimation of all of the relevant camera parameters. Experimental results are presented, which illustrate the performance of the calibration method and validate the approachThis research was sponsored by the MORPH EU FP7-Project under Grant Agreement FP7-ICT-2011-7-288704, the Spanish National Project OMNIUS (Lightweight robot for OMNidirectional Underwater Surveying and telepresence) under Agreement CTM2013-46718-R, the Generalitat de Catalunya through the ACCIO (Agencia per a la competitivitat de l'empresa de la Generalitat de Catalunya)/TecnioSpring program (TECSPR14-1-0050), with the support of "la Secretaria d'Universitats i Recerca del Departament d'Economia i Coneixement de la Generalitat de Catalunya" and the University of Girona under a grant for the formation of researcher

Close-range tracking of underwater vehicles using light beacons

This paper presents a new tracking system for autonomous underwater vehicles (AUVs) navigating in a close formation, based on computer vision and the use of active light markers. While acoustic localization can be very effective from medium to long distances, it is not so advantageous in short distances when the safety of the vehicles requires higher accuracy and update rates. The proposed system allows the estimation of the pose of a target vehicle at short ranges, with high accuracy and execution speed. To extend the field of view, an omnidirectional camera is used. This camera provides a full coverage of the lower hemisphere and enables the concurrent tracking of multiple vehicles in different positions. The system was evaluated in real sea conditions by tracking vehicles in mapping missions, where it demonstrated robust operation during extended periods of timeThis research was sponsored by the MORPH EU FP7-Project under Grant Agreement FP7-ICT-2011-7-288704, the Spanish National Project OMNIUS (Lightweight robot for omnidirectional underwater surveying and telepresence) under Agreement CTM2013-46718-R, the ROBOCADEMY (European Academy for Marine and Underwater Robotics) EU FP7-Project under Grant Agreement 608096, the Generalitat de Catalunya through the ACCIO (Agència per a la competitivitat de l’empresa de la Generalitat de Catalunya)/TecnioSpring program (TECSPR14-1-0050), with the support of “la Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya