Six-Degree-of-Freedom Localization With a 3-Axis Accelerometer and a 2-Axis Magnetometer for Magnetic Capsule Endoscopy

This letter presents a new localization method for magnetic capsule endoscopes that uses sensors internal to the capsule, but aims to relieve some of the previous limitations associated with this paradigm. The method estimates the six-degree-of-freedom capsule pose with no prior pose information other than the knowledge that it resides within a particular workspace. Internal to the capsule, it requires a 3-axis accelerometer, a 2-axis magnetometer (or 3-axis magnetometer with one axis saturated or disabled), a microcontroller capable of wireless communication, and a radio frequency antenna, all of which can be integrated into a single printed circuit board. The method is applicable to both of the common configurations of the internal permanent magnet. In a set of simulations and experiments, we show that the localization accuracy is comparable to what has been obtained with prior methods that have required more complexity.