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Vision system is the important equipment for Unmanned Surface Vehicle (USV) to find obstacles and monitor surrounding environment. There are popular calibration methods for vision system used indoor and outdoor on land. However, the USV has to be transported, hoisted and deployed, and calibrated parameters may be changed in the process. Consequently, it is desired to calibrate the vision system in...
This paper presents the bio-inspired underwater 3D SLAM algorithm called DolphinSLAM. First, every module of the DolphinSLAM algorithm is explained. Then, the effects of parameter variations regarding the parameters of the DolphinSLAM algorithm are investigated based on the use of the Underwater Simulator (UWSim). The parameters of interest are i) the image feature extractors, ii) the vocabulary size...
As buoyancy-driven underwater gliders which have multi-functionality become more and more important instruments of monitoring and exploring the ocean, it is momentous to research and verify the performance of hardware of glider and the function of control software by establishing mathematical model and simulation. So a semi-physical motion simulation system of buoyancy-driven underwater glider is...
Underwater 3D object reconstruction is one of the most essential and fundamental tasks in ocean investigations. In this paper, we try to capture the inherent geometrical variation of 3D objects at multiple visual angels with the underwater vehicles and develop a novel underwater 3D object reconstruction model for the continuous video stream. Image enhancement will be first taken into consideration...
Image restoration methods have been made to repair images that have some kind of degradation. Most of these methods are designed to deal with the degradation caused by the over-land effects. However, when the images was captured in underwater environments, there are different properties that can degrade the image in unusual ways. This work aims to evaluate how the popular image restoration methods...
As we endeavor to deploy and maintain evermore complex infrastructure underwater, the tools used for subsea maintenance and intervention must also evolve to meet new needs. Whether for scientific sampling and exploration, subsea mining, offshore oil & gas production, or installation and maintenance of marine renewable energy devices, there is a regular and increasing need for intervention to conduct...
Autonomous underwater vehicles (AUVs) often perform high-resolution survey missions. Such missions are often planned on low resolution bathymetry maps using offline coverage planning methods, e.g., using a standard lawn-mower trajectory that is adapted to the coarse-resolution representation of the terrain. We present in this paper an approach to adapt the exploration online during the mission, namely...
Robust and accurate navigation of underwater vehicles is an essential cornerstone for mission success. Integrative techniques, e.g., using inertial navigation or Doppler velocity logs (DVL), can show significant drift. Even absolute input, such as GNSS input or magnetometers, can either be biased by surrounding structures or very noisy. For good navigation performance in critical maneuvers close to...
This paper addresses the three-dimensional (3D) reconstruction of a floating structure with an unmanned surface vehicle (USV). Onboard lidar and sonar sensors are employed to collect a volumetric point cloud of the structure both above and below the waterline. These measurements are obtained in the vehicle-fixed frame; thus, for successful 3D reconstruction, precision estimation of trajectory and...
Today, in our landscape perception exists a gap that needs to be fulfilled. It's important to increase the coverage, temporal and spatial resolution in order to cover this gap, as well as reduce costs with human resources that usually take this kind of tasks. Unmanned Autonomous vehicles with their inherent autonomy and reduced needs of human and communication resources, can provide additional capabilities...
This paper adopts guidance and control framework to address the problem of path following for an under-actuated autonomous underwater vehicle (AUV) moving in three dimensional (3D) space. First, based on the error dynamics in the moving path frame, the desired pitch angle and yaw angle are designed in kinematics by 3D Line-of-Sight (LOS) guidance law. Subsequently, the desired pitch and yaw angular...
In this paper, a path planning system is proposed for optimal motions of underwater glider in three-dimensional (3D) space. Inspired by the Dubins Paths consisting of straight lines and circular arcs, this paper presents the 3D Dubins curve to accommodate the characteristic glider motions, including sawtooth motion and spiral motion. This modified 3D Dubins scheme is combined with genetic algorithm...
This paper proposes visual-based underwater vehicle docking/homing system under the environment especially simulated for deep sea trial. Instead of measuring absolute position of vehicle using other non-contact sensors, estimation of the robot's relative position and posture (pose) using dual-eyes cameras and 3D target object is proposed. For relative pose estimation, 3D model-based recognition approach...
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