A Differential Signal and Extended-Kalman-Filter-Based Anti-Interference Magnetic Tracking Method for Surgical Scenes

Magnetic tracking is a promising technique for surgery navigation. However, the magnetic interference (MI) generated in the operating room causes great disturbances to the magnetic tracking system. To attenuate the influence of the MI and improve the tracking performance, this article proposes a differential-based extended Kalman filter (D-EKF) algorithm. Different from conventional algorithms, in the D-EKF, differential units are constructed using the Hamiltonian circle method with the help of a dummy vertex. This helps to attenuate the influence of the MI. Furthermore, an extended Kalman filter is used to estimate the magnet states via the differential signals. The performance of the proposed algorithm is tested in a surgical scene equipped with common surgical instruments and a surgical robot. The experimental results show that the disturbances of MIs can be well attenuated by the proposed algorithm, and high robustness against MI is achieved.