A comprehensive method for magnetic sensor calibration: a precise system for 3-D tracking of the tongue movements

Magnetic localization has been used in a variety of applications, including the medical field. Small magnetic tracers are often modeled as dipoles and localization has been achieved by solving well-defined dipole equations. However, in practice, the precise calculation of the tracer location not only depends on solving the highly nonlinear dipole equations through numerical algorithms but also on the precision of the magnetic sensor, accuracy of the tracer magnetization, and the earth magnetic field (EMF) measurements. We have developed and implemented a comprehensive calibration method that addresses all of the aforementioned factors. We evaluated this method in a bench-top setting by moving the tracer along controlled trajectories. We also conducted several experiments to track the tongue movement in a human subject.