Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

One-Degree-of-Freedom System01:24

One-Degree-of-Freedom System

473
In mechanical engineering, one-degree-of-freedom systems form the basis of a wide range of electrical and mechanical components. Using these models, engineers can predict the behavior of various parts in a larger system, which gives them insight into how different forces interact with each other.
A one-degree-of-freedom system is defined by an independent variable that determines its state and behavior. One example of a one-degree-of-freedom system is a simple harmonic oscillator, such as a...
473
Torque Free Motion01:15

Torque Free Motion

467
The torque-free motion refers to the movement of a rigid body in space when no external torques are acting upon it. This type of motion can be observed in environments where there are no external forces or frictions, like in outer space. For example, a rotation of Mars in space is a torque-free motion. Mars is an axisymmetric object, meaning it has an axis of symmetry along which it rotates, designated as the z-axis. The rotating frame of reference is defined such that the center of mass of...
467
Relative Motion Analysis using Rotating Axes01:25

Relative Motion Analysis using Rotating Axes

452
Consider a component AB undergoing a linear motion. Along with a linear motion, point B also rotates around point A. To comprehend this complex movement, position vectors for both points A and B are established using a stationary reference frame.
However, to express the relative position of point B relative to point A, an additional frame of reference, denoted as x'y', is necessary. This additional frame not only translates but also rotates relative to the fixed frame, making it...
452
Relative Motion Analysis using Rotating Axes-Problem Solving01:29

Relative Motion Analysis using Rotating Axes-Problem Solving

394
Consider a crane whose telescopic boom rotates with an angular velocity of 0.04 rad/s and angular acceleration of 0.02 rad/s2. Along with the rotation, the boom also extends linearly with a uniform speed of 5 m/s. The extension of the boom is measured at point D, which is measured with respect to the fixed point C on the other end of the boom. For the given instant, the distance between points C and D is 60 meters.
Here, in order to determine the magnitude of velocity and acceleration for point...
394
Open and closed-loop control systems01:17

Open and closed-loop control systems

686
Control systems are foundational elements in automation and engineering. They are broadly categorized into open-loop and closed-loop systems. These classifications hinge on the presence or absence of feedback mechanisms, significantly influencing the system's performance, complexity, and application.
An open-loop control system operates without feedback from the output. It consists of two primary elements: the controller and the controlled process. The controller receives an input signal...
686
Absolute Motion Analysis- General Plane Motion01:24

Absolute Motion Analysis- General Plane Motion

218
Visualize a drone, with its propellers spinning rapidly, hovering mid-air. The fascinating movements and operations of this drone can be comprehended by applying the principle of general plane motion.
As the drone's propellers rotate, an upward force is generated that counteracts the force of gravity, enabling the drone to lift off from the ground. This initial movement of the drone is along a straight path, representing a form of translational motion. In this phase, every point on the...
218

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Prospective Head Motion Correction in T1- and T2-Weighted Long Echo Train Sequences Using Servo Navigation.

Magnetic resonance in medicine·2026
Same author

Direct MRI of collagen.

eLife·2026
Same author

Autonomy for MRI Field Cameras: Synchronization, Self-Calibration, and Sequence Detection.

Magnetic resonance in medicine·2026
Same author

Motion- and Field-Robust Mesoscopic Whole-Brain <math><semantics><mrow><msubsup><mi>T</mi> <mn>2</mn> <mo>*</mo></msubsup></mrow> <annotation>$$ {T}_2^{\ast } $$</annotation></semantics></math> -Weighted Imaging at 7 and 11.7 T Using Servo Navigation.

Magnetic resonance in medicine·2026
Same author

Making RF coils MR-invisible by additive manufacturing using magnetically filled polymer.

Magnetic resonance in medicine·2025
Same author

A unipolar head gradient for high-field MRI without encoding ambiguity.

Magnetic resonance in medicine·2025

Related Experiment Video

Updated: Jun 15, 2025

Controlled Rotation of Human Observers in a Virtual Reality Environment
09:11

Controlled Rotation of Human Observers in a Virtual Reality Environment

Published on: April 21, 2022

2.5K

Run-time motion and first-order shim control by expanded servo navigation.

Malte Riedel1, Thomas Ulrich1, Klaas P Pruessmann1

  • 1Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Switzerland.

Magnetic Resonance in Medicine
|August 27, 2024
PubMed
Summary

This study introduces a navigator-based method for precise, real-time motion and gradient shim field correction in 3D brain imaging. The technique offers fast processing and minimal calibration, enhancing image quality for both phantom and in vivo scans.

Keywords:
feedback controlfield correctionhead motionlinear regressionmotion correctionorbital navigators

More Related Videos

A Structured Rehabilitation Protocol for Improved Multifunctional Prosthetic Control: A Case Study
06:58

A Structured Rehabilitation Protocol for Improved Multifunctional Prosthetic Control: A Case Study

Published on: November 6, 2015

9.4K
Method to Measure Tone of Axial and Proximal Muscle
10:41

Method to Measure Tone of Axial and Proximal Muscle

Published on: December 14, 2011

17.5K

Related Experiment Videos

Last Updated: Jun 15, 2025

Controlled Rotation of Human Observers in a Virtual Reality Environment
09:11

Controlled Rotation of Human Observers in a Virtual Reality Environment

Published on: April 21, 2022

2.5K
A Structured Rehabilitation Protocol for Improved Multifunctional Prosthetic Control: A Case Study
06:58

A Structured Rehabilitation Protocol for Improved Multifunctional Prosthetic Control: A Case Study

Published on: November 6, 2015

9.4K
Method to Measure Tone of Axial and Proximal Muscle
10:41

Method to Measure Tone of Axial and Proximal Muscle

Published on: December 14, 2011

17.5K

Area of Science:

  • Medical Imaging
  • Magnetic Resonance Imaging (MRI) Physics

Background:

  • Motion and magnetic field fluctuations significantly degrade the quality of 3D brain MRI.
  • Precise correction methods are crucial for high-resolution neuroimaging.

Purpose of the Study:

  • To develop a navigator-based system for real-time, high-precision motion and first-order gradient shim field correction in 3D human brain imaging.
  • To achieve this with minimal calibration, acquisition time, and fast processing.

Main Methods:

  • Extended a complex-valued linear perturbation model with feedback control to estimate and correct gradient shim fields using orbital navigators.
  • Presented two approaches: finite differences with additional navigators and a projection-based approximation.
  • Incorporated noise decorrelation to reduce parameter biases.

Main Results:

  • Achieved robust motion and gradient shim corrections, significantly improving image quality in phantom and in vivo experiments.
  • Successfully corrected for magnet drifts, gradient field perturbations, and bottle phantom shifts.
  • Demonstrated mitigation of torso motion effects and robustness to head motion in in vivo scans, with high precision.

Conclusions:

  • The navigator-based method provides accurate, high-precision, real-time motion and field corrections.
  • The technique has minimal impact on MRI sequences and low calibration requirements.