This paper presents UWSim: a new software tool for visualization and simulation of underwater robotic missions. The software visualizes an underwater virtual scenario that can be configured using standard modeling software. Controllable underwater vehicles, surface vessels and robotic manipulators, as well as simulated sensors, can be added to the scene and accessed externally through network interfaces. This allows to easily integrate the simulation and visualization tool with existing control architectures, thus allowing hardware-in-the-loop simulations (HIL). UWSim has been successfully used for simulating the logics of underwater intervention missions and for reproducing real missions from the captured logs. The software is offered as open source, thus filling a gap in the underwater robotics community, where commercial simulators oriented to ROV pilot training predominate.

/pdf/an-open-source-tool-for-simulation-and-supervision-of-hsbtypkdcs.pdf

An open source tool for simulation and supervision of underwater intervention missions

This paper addresses video tracking, the problem of following moving targets automatically over a video sequence, and brings three main contributions. First, we give a concise introduction to video tracking in computer vision, including design requirements and a review of recent techniques, with some details of selected algorithms. Second, we give an overview of 28 recent papers on subsea video tracking and related motion analysis problems, arguably capturing the state-of-the-art of subsea video tracking. We summarize key features in a comparative, at-a-glance table, and discuss this work in comparison to the state-of-the-art in computer vision. Third, we identify well-proven computer vision techniques not yet embraced by the subsea research community, suggesting useful research directions for the subsea video processing community

Video Tracking: A Concise Survey

An adaptive fuzzy sliding mode controller for remotely operated underwater vehicles

Nowadays, the surveillance and inspection of underwater installations, such as power and telecommunication cables and pipelines, is carried out by operators that, being on the surface, drive a remotely operated vehicle (ROV) with cameras mounted over it. This is a tedious and high time-consuming task, easily prone to errors mainly because of loss of attention or fatigue of the human operator. Besides, the complexity of the task is increased by the lack of quality of typical seabed images, which are mainly characterised by blurring, non-uniform illumination, lack of contrast and instability in the vehicle motion. In this study, the development of a vision system guiding an autonomous underwater vehicle (AUV) able to detect and track automatically an underwater power cable laid on the seabed is the main concern. The vision system that is proposed tracks the cable with an average success rate above 90%. The system has been tested using sequences coming from a video tape obtained in several tracking sessions of various real cables with a ROV driven from the surface. These cables were installed several years ago, so that the images do not present highly contrasted cables over a salady seabed; on the contrary, these cables are partially covered in algae or sand, and are surrounded by other algae and rocks, thus making the sequences highly realistic.

A vision system for an underwater cable tracker

This article presents a discussion of recent advances in underwater photogrammetric survey, illustrated by case studies in Scotland and Denmark between 2011 and 2013. Results from field trials are discussed with the aim of illustrating practical low-cost solutions for recording underwater archaeological sites in 3D using photogrammetry and using this data to offer enhanced recording, interpretation and analysis. We argue that the availability of integrated multi-image photogrammetry software, highly light-sensitive digital sensors and wide-aperture compact cameras, now allow for simple work flows with minimal equipment and excellent natural colour images even at depths of up to 30 m. This has changed the possibilities for underwater photogrammetric recording, which can now be done on a small scale, through the use of a single camera and automated work flow. The intention of this paper is to demonstrate the quality and versatility of the ‘one camera/ambient light/integrated software’ technique through the case studies presented and the results derived from this process. We also demonstrate how the 3D data generated can be subjected to surface analysis techniques to enhance detail and to generate data-driven fly-throughs and reconstructions, opening the door to new avenues of engagement with both specialists and the wider public.

http://corkfits.net.temporary-domain.com/articles/files/mccarthy2014.pdf

Multi-image Photogrammetry for Underwater Archaeological Site Recording: An Accessible, Diver-Based Approach

Remotely operated vehicle depth control

Robust real-time detection of an underwater pipeline

This paper describes a suite of automated tools to produce underwater georeferenced cartographic data that includes archaeologically relevant information. The automated data-processing methodology ...

Underwater cartography for archaeology in the VENUS project

In this paper we address the problem of evaluating some of the hydrodynamics parameters that characterize the behavior of an unmanned underwater vehicle. To this aim, we propose a procedure that can be implemented by an automatic guidance system during normal operation (e. g. at the beginning of a mission or at any time the configuration of the vehicle is modified), provided it is possible to exert a known force on the vehicle (in particular, by means of the thrusters) and to measure the resulting acceleration (e. g. by an inertial measuring sensor). Preliminary experimental work for validating this procedure on a small, work class ROV is described.

Evaluation of hydrodynamics parameters of a UUV. A preliminary study

The work presents a real-time underwater imaging system for identification and tracking of a submarine pipeline on a sequence of recorded images. The main novelty of this work relies on adopting an automatic approach that is entirely based on the analysis and interpretation of visual data, in spite of the various limitations upon the ability to image underwater objects. The analysis of the data is performed starting from image processing operations (like filtering, profile analysis, feature enhancement) implemented on a dedicated board. Then, the system employs an efficient dynamic process for recognizing the two contours of the pipeline. In each frame the system is able to determine the equations of the two straight lines corresponding to the pipeline contours. The system reaches satisfactory performances in real time operation: up to eight frames per second on a Pentium based PC. The results of this work are somewhat more meaningful as the input images were acquired by three cameras, mounted on a remotely operated vehicle travelling at one nautical mile an hour, without any attention either to illumination conditions or stability of cameras. This work is originated from the interest of Snamprogetti in enhancing the level of automation in submarine pipeline inspection.

Silvia Maria Zanoli

Papers

Remotely operated vehicle depth control

Robust real-time detection of an underwater pipeline

Underwater cartography for archaeology in the VENUS project

Evaluation of hydrodynamics parameters of a UUV. A preliminary study

Imaging approach to real-time tracking of submarine pipeline