By Gareth Douglas Cole, M.S. Washington State University May 2007 Chair: Sankar Jayaram Electromagnetic tracking systems used in virtual reality applications are subject to tracking error due to magnetic field distortions caused by metallic objects in the environment which increases with increased distance from the transmitter. These problems can lead to a significant decrease in tracking perfo...

This study investigated a functional calibration method to define the Cartesian bone-embedded anatomical frame necessary to calculate 3D joint angles. This method was combined with an inertial ambulatory system and applied to the measurement of 3D knee joint angles during gait. This combination was compared to a magnetic tracker system associated with a functional and postural calibration metho...

Magnetometers combined with inertial sensors are widely used for orientation estimation, and calibrations are necessary to achieve high accuracy. This paper presents a complete tri-axis magnetometer calibration algorithm with a gyro auxiliary. The magnetic distortions and sensor errors, including the misalignment error between the magnetometer and assembled platform, are compensated after calib...

This paper presents the latest design and implementation of the Magnetic, Angular Rate, and Gravity (MARC) sensor module. The MARG sensor module is designed for measuring 3-DOF orientations in real time without singularities. Each MARG sensor contains orthogonally mounted triads of micromachined rate sensors, accelerometers, and magnetometers for a total of nine sensor components. With an integ...

PURPOSE To demonstrate the degree of the cerebral blood flow (CBF) estimation bias that could arise from distortion of the arterial input function (AIF) as a result of partial-volume effects (PVEs) in dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI). MATERIALS AND METHODS A model of the volume fraction an artery occupies in a voxel was devised, and a mathematical relatio...

The Lorentz force flowmeter (LFF) is a measuring device utilizing localized static magnetic fields for the non-contact measurement of the flow rate in electrically conducting fluids. In case of highly aggressive or high-temperature conductive fluids, it is difficult to reproduce in a laboratory the conditions typically met in application. Hence, calibration becomes a difficult task. For the LFF...