Methods and Apparatus for Improved Electromagnetic Tracking and Localization

A method for electromagnetic (EM) tracking or localization, comprising:

• providing, as input to a probabilistic SLAM algorithm:
• an indication of relative locations of one or more transmitter and sensor with respect to one or more instruments;
• optionally, a model of the one or more instrument flexibility;
• an uncertainty associated with each measurement;
• and
• an expected behavior of the one or more instrument, using an equation of motion or dynamic model with motion constraints;
• using the SLAM algorithm to simultaneously estimate a pose of the one or more instrument and update a field distortion map, or parameters of a field distortion model;
• estimating field distortion using currently-available information of the field distortion map and estimating field distortion in the vicinity of the one or more instrument, and using the estimates for future measurement compensation;
• and
• continuously observing variations in the field distortion map over time to differentiate regions with continuous changes from regions with constant field distortion, and providing feedback to a field distortion estimator, including indicating to what degree each region of the map is expected to change;
• wherein simultaneous field distortion mapping and electromagnetic tracking or localization of the one or more instrument is provided in real time.

Apparatus for electromagnetic (EM) tracking or localization, comprising:

• one or more EM transmitters and receivers (sensors, or trackers);
• a processor that receives and/or processes one or more of
• an indication of relative locations of the one or more transmitter and sensor with respect to one or more instrument;
• optionally, a model of the one or more instrument flexibility;
• optionally, a measurement uncertainty analyzer that reports an uncertainty associated with each measurement;
• optionally, a field distortion compensation technique;
• an equation of motion or dynamic model with motion constraints, such as a nonholonomic constraint, that describes an expected behavior of the one or more instrument;
• wherein the processor outputs a result wherein the one or more instrument is localized or reconstructed in in real-time or off-line.

A method for electromagnetic (EM) tracking or localization, comprising:

• providing, as input to a processor that includes a filtering algorithm:
• an indication of relative locations of one or more transmitter and sensor with respect to one or more instrument;
• optionally, a model of the one or more instrument flexibility;
• a motion model with constraints that describe an expected behavior of each of the one or more instrument;
• analyzing a measurement uncertainty and reporting an uncertainty associated with each measurement;
• optionally applying a field distortion compensation technique;
• using the filtering algorithm to reconstruct and/or localize the one or more instrument path;
• wherein the one or more instrument path is tracked, localized, or reconstructed in in real-time or off-line.