Results 261 to 270 of about 157,979 (303)

Automatic vessel tracking and measurement for Doppler studies

Ultrasound in Medicine & Biology, 1990
In this initial report, an imaging technique is described for automatically recognising the walls of a blood vessel during Doppler measurements, and hence automatically adjusting the position of the sample volume. The method reduces the inherently two-dimensional edge detection problem to a one-dimensional one, and iterates over several imaging frames ...
L S, Wilson, M J, Dadd, R W, Gill
openaire   +2 more sources

DP Systems for Track Control of Dredging Vessels

IFAC Proceedings Volumes, 2012
Abstract The problems of implementing special control functionality for trailing suction dredgers in dynamic positioning (DP) systems are considered, focusing mainly on the dredging track control modes. The motion controller is proposed which provides the trajectory steering with the draghead under restrictions, imposed by the dredging process and ...
Loginov, Andrey, Proskurnikov, Anton, Ambrosovskaya, Elena, Romaev, Dmitry   +3 more
openaire   +1 more source

Nonlinear tracking of underactuated surface vessels

Proceedings of 35th IEEE Conference on Decision and Control, 2002
A control law for tracking of underactuated surface vessels is presented. Optimal trajectories for surface vessels are given as combinations of arcs of circles and line segments. It is shown how optimal trajectories can be made smooth by a technique called splines, and how these trajectories can be stabilized by backstepping. The control law depends on
openaire   +1 more source

Adaptive tracking control of underactuated surface vessels

Proceedings of the 2001 IEEE International Conference on Control Applications (CCA'01) (Cat. No.01CH37204), 2002
We design a continuous, time-varying tracking controller for an underactuated surface vessel in the presence of uncertainty associated with the hydrodynamic damping coefficients. A Lyapunov-based approach is used to ensure that the position/orientation tracking error is ultimately confined to a ball that can be made arbitrarily small.
A. Behal, D.M. Dawson, B. Xian, P. Setlur   +3 more
openaire   +1 more source

Tracking control algorithms design of underactuated vessels

2017 29th Chinese Control And Decision Conference (CCDC), 2017
The cooperative tracking control problem of autonomous vessels is analyzed in this paper. Firstly, we capture the properties of motion constraints of marine vessels. We relate these constraints to previous analysis to suggest ways that they can be bounded in practice.
Yuqing Chen, Zhipeng Shen, Chen Guo
openaire   +1 more source

Motion Planning and Tracking for Marine Vessels

Volume 5: Ocean Engineering, 2013
Trajectory tracking is an issue of vital practical importance for manoeuvreing of marine vessels and dynamic position system in many offshore oil field operations. In this work, a flatness based approach is proposed on the tracking control design to define open loop trajectories for a simplified model of the underactuated Hovercraft.
José Oniram de Aquino Limaverde Filho, Eugênio Liborio Feitosa Fortaleza   +1 more
openaire   +1 more source

Frequency domain tracking of passive vessel harmonics.

The Journal of the Acoustical Society of America, 2009
This paper presents a method for passive acoustic detection and tracking of small vessels in noisy, shallow water marine environments. Passive spectra of boats include broadband noise as well as tones that are harmonics of the engine speed and shaft/propeller rotation.
George Ogden, Lisa Zurk, Martin Siderius, Eric Sorensen, Josh Meyers, Shari Matzner, Mark Jones   +6 more
openaire   +1 more source

4D vessel segmentation and tracking in Ultrasound

2012 19th IEEE International Conference on Image Processing, 2012
In this paper we describe a fast method to segment and track a vessel of interest in 4D (i.e. 3D + time) Ultrasound images. An initial 2D seed is used to initialize a single spatial Kalman-Filter tracker which tracks the vessel center-line in 3D. The 3D vessel is then segmented using a fast area weighted active contour method.
Kedar A. Patwardhan, Yongjian Yu, Sandeep Gupta, Aaron Dentinger, David Mills   +4 more
openaire   +1 more source

Sliding-Mode Tracking Control of Surface Vessels

IEEE Transactions on Industrial Electronics, 2008
A sliding-mode control law is presented and experimentally implemented for trajectory tracking of underactuated autonomous surface vessels. The control law is developed by introducing a first-order sliding surface in terms of surge tracking errors and a second-order surface in terms of lateral motion tracking errors.
Ashrafiuon, Hashem., Muske, Kenneth R., McNinch, Lucas C., Soltan, Reza A.   +3 more
openaire   +1 more source

A track fusion method of a vessel

SPIE Proceedings, 2015
Track data of vessels is usually sampled by radar and AIS devices. The accuracy of data and sample cycle of radar systems are different from AIS’s. Track fusion of radar and AIS data can improve the accuracy and reliability of vessel tracks. This paper researches the fusion method of vessel tracks based on the radar and AIS data.
Wuxiong Xu, Dong Zhong, Siqing Wu, Hao Ni   +3 more
openaire   +1 more source