55 research outputs found
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
Optical data processing in the context of the picmar project
The inspection of the seafloor is a fundamental task during the implantation,
maintenance and dismantling of marine and oceanic infrastructures. The
PICMAR project is intended to overcome the existing limitations of the current inspection
systems. In the developed framework, the whole sensor-data processing is
treated, improving the state of the art in topics such as multimodal data registration
and 2D / 3D data blending, and going beyond in others such as automatic data
classification and change detection. In this paper, the image processing pipeline
is explained, involving preprocessing, geometrical and photometrical registration
and change detection, and some of the obtained results are shown.Peer Reviewe
3D data processing for underwater inspection and monitoring
Ever-growing attention has been given to the monitoring and inspection
of underwater man-made structures for scientific and technical purposes. However,
most of the related tasks are still involving the use of scuba divers.
In this paper, we propose a data processing pipeline that allows automatic inspection
and monitoring of underwater structures using 2.5D and 3D data provided by
either acoustic or optical sensors.Peer Reviewe
Tectonic structure, evolution, and the nature of oceanic core complexes and their detachment fault zones (13°20′N and 13°30′N, Mid Atlantic Ridge)
Microbathymetry data, in situ observations, and sampling along the 138200N and 138200N oceanic
core complexes (OCCs) reveal mechanisms of detachment fault denudation at the seafloor, links between tectonic
extension and mass wasting, and expose the nature of corrugations, ubiquitous at OCCs. In the initial
stages of detachment faulting and high-angle fault, scarps show extensive mass wasting that reduces their
slope. Flexural rotation further lowers scarp slope, hinders mass wasting, resulting in morphologically complex
chaotic terrain between the breakaway and the denuded corrugated surface. Extension and drag along the fault
plane uplifts a wedge of hangingwall material (apron). The detachment surface emerges along a continuous
moat that sheds rocks and covers it with unconsolidated rubble, while local slumping emplaces rubble ridges
overlying corrugations. The detachment fault zone is a set of anostomosed slip planes, elongated in the alongextension
direction. Slip planes bind fault rock bodies defining the corrugations observed in microbathymetry
and sonar. Fault planes with extension-parallel stria are exposed along corrugation flanks, where the rubble cover
is shed. Detachment fault rocks are primarily basalt fault breccia at 138200N OCC, and gabbro and peridotite
at 138300N, demonstrating that brittle strain localization in shallow lithosphere form corrugations, regardless of
lithologies in the detachment zone. Finally, faulting and volcanism dismember the 138300N OCC, with widespread
present and past hydrothermal activity (Semenov fields), while the Irinovskoe hydrothermal field at the
138200N core complex suggests a magmatic source within the footwall. These results confirm the ubiquitous
relationship between hydrothermal activity and oceanic detachment formation and evolution
Efficient 3D scene modeling and mosaicing
El modelat d'escenes és clau en un gran ventall d'aplicacions que van des de la generació mapes fins a la realitat augmentada. Aquesta tesis presenta una solució completa per a la creació de models 3D amb textura. En primer lloc es presenta un mètode de Structure from Motion seqüencial, a on el model 3D de l'entorn s'actualitza a mesura que s'adquireix nova informació visual. La proposta és més precisa i robusta que l'estat de l'art. També s'ha desenvolupat un mètode online, basat en visual bag-of-words, per a la detecció eficient de llaços. Essent una tècnica completament seqüencial i automà tica, permet la reducció de deriva, millorant la navegació i construcció de mapes. Per tal de construir mapes en à rees extenses, es proposa un algorisme de simplificació de models 3D, orientat a aplicacions online. L'eficiència de les propostes s'ha comparat amb altres mètodes utilitzant diversos conjunts de dades submarines i terrestres.Scene modeling has a key role in applications ranging from visual mapping to augmented reality. This thesis presents an end-to-end solution for creating accurate, automatic 3D textured models, with contributions at different levels. First, we discuss a method developed within the framework of sequential Structure from Motion, where a 3D model of the environment is maintained and updated as visual information becomes available. The technique is more accurate and robust than state-of-the-art 3D modeling approaches. We also develop an online effcient loop-closure detection algorithm, allowing the reduction of drift and uncertainties for mapping and navigation. Inspired from visual bag-of-words, the technique is entirely sequential and automatic. Lastly, motivated by the need to map large areas, we propose a 3D model simplification oriented towards online applications. We discuss the efficiency of the proposals and compare them with state-of-the-art approaches, using a series of challenging datasets both in underwater and outdoor scenarios
Online Robust 3D Mapping Using Structure from Motion Cues
This paper presents a complete solution for creating accurate 3D textured models from monocular video sequences. The methods are developed within the framework of sequential structure from motion, where a 3D model of the environment is maintained and updated as new visual information becomes available. The camera position is recovered by directly associating the 3D scene model with local image observations. Compared to standard structure from motion techniques, this approach decreases the error accumulation while increasing the robustness to scene occlusions and feature association failures. The obtained 3D information is used to generate high quality, composite visual maps of the scene (mosaics). The visual maps are used to create texture-mapped, realistic views of the scen
- …