A Six-Dimensional Magnetic Localization Algorithm for a Rectangular Magnet Objective Based on a Particle Swarm Optimizer

To build a wireless capsule endoscope with active external guidance for controllable and interactive diagnosis on the gastrointestinal tract, it is necessary to track the capsule´s 3-D position and 3-D orientation. An approach to tracking is to enclose a small rectangular permanent magnet in the capsule. The magnetic field produced around the body by the rectangular magnet can be detected by magnetic sensors outside the patient´s body. With these detected magnetic sensor data, the 3-D localization and 3-D orientation parameters can be computed by an appropriate algorithm based on the mathematical model of the rectangular magnet´s magnetic field. We tried several nonlinear optimization algorithms, and simulation experiments show that the particle swarm optimization algorithm can work effectively with good accuracy when the magnet moves within a predetermined range.