Patent ID: 6484131
Filing Date: 2002-11-19
Classification: G06T

Abstract:
A pose tracking apparatus operative to track the pose of a moving object based on magnetic flux measurements taken in the vicinity of the moving object, the pose tracking apparatus comprising:a non-linear Kalman filter-based tracker operative to receive magnetic flux measurements performed in the vicinity of the moving object, and to operate a non-linear Kalman-type filter on said measurements, thereby to generate information regarding the pose of the moving object; and a pose indicator operative to provide an output indication of said information regarding the pose of the moving object, wherein the non-linear tracker employs a Biot-Savart transformation from the pose of the moving object to the magnetic flux measurements taken in its vicinity, and wherein employing the Biot-Savart transformation comprises computing a function h of a state vector, as follows: h&af;(Î¾)=C0R3&it;(3&it;A1&it;A2R2-A3)where C0 is a coefficient, R is the distance between a detector detecting the magnetic flux measurements within a transmitter array, and a transmitter inducing a magnetic flux sampled by said measurements, and A1=&dgr;x sin(&thgr;s)cos(&phgr;s)+&dgr;y sin(&thgr;s)sin(&phgr;s)+&dgr;z cos(&thgr;s) A2=&dgr;Ã—sin(&thgr;d)cos(&phgr;d)+&dgr;y sin(&thgr;d)sin(&phgr;d)+&dgr;z cos(&thgr;d) A3=sin(&thgr;s)cos(&phgr;s)sin(&thgr;d)cos(&phgr;d)+sin(&thgr;s)sin(&phgr;s)sin(&thgr;d)sin(&phgr;d)+cos(&phgr;s)coS(&phgr;d) and wherein the pose of the detector is (xd, yd, zd, &thgr;d, &phgr;d) and the pose of the transmitter is (xs, ys, zs, &thgr;s, &phgr;s), and where &dgr;x, &dgr;y and &dgr;z denote the distance between the x, y and z components, respectively, of the detector's pose and the transmitter's pose.