Magnetic Sensors and Medical Bio-technology -Measuring Vibrations, Displacements, and Articulatory Movements-

Recent developments in non-contact magnetic sensing systems are reviewed, with respect to several applications in biomedical fields. Spatial information of a magnetic source can be obtained by measuring the direction and intensity of a magnetic field. Using a magnetometer sensor as a displacement sensor for microvibration, mechanocardiogram and eyelid vibrations can be stably and easily detected by fixing a small magnetic disk on the chest wall or on the eyelids. Articulatory movements during speech can be observed to aid in understanding the speech production process. The magnetic field induced by a magnetic rod attached to a desired point of the tongue surface is detected by sensors as a measure of the motion in a coordinate system after appropriate signal processing.