Magnetometer Surgical Device
A magnetometer-based metal detection device and methods of use are described. The device includes a proximal portion, a central body and a distal portion, and at least one magnetometer positioned within or on the distal portion. The at least one magnetometer includes at least one sensor capable of sensing a magnetic field in three orthogonal axes. Also described is a method of calibrating the device to achieve rotational invariance, and a method of determining a directionality or directional line along which a target metal object lies.
1 . A magnetometer-based metal detection device, comprising:
a proximal portion, a central body and a distal portion; and at least one magnetometer positioned within or on the distal portion,
wherein the at least one magnetometer includes at least one sensor capable of sensing a magnetic field in three orthogonal axes.
2 . The device of claim 1 , wherein the distal portion is adjustable.
3 . The device of claim 2 , further comprising an actuator positioned within or on the proximal portion, wherein the actuator is capable of directing movement of the adjustable distal portion.
4 . The device of claim 1 , further comprising an accelerometer positioned within or on the distal portion.
5 . The device of claim 1 , further comprising a permanent magnet positioned within or on the distal portion.
6 . The device of claim 1 , further comprising an electromagnet positioned within or on the distal portion.
7 . The device of claim 1 , further comprising a controller electrically connected to the at least one magnetometer.
8 . The device of claim 7 , further comprising a user interface communicatively connected to the controller.
9 . The device of claim 8 , further comprising a memory and programming logic resident on the memory, wherein the programming logic is capable of calibrating the device to achieve rotational invariance.
10 . The device of claim 9 , wherein the programming logic is further capable of determining a directionality or directional line along which a target metal object lies.
11 . The device of claim 10 , further comprising an accelerometer positioned within or on the distal portion, and wherein the programming logic is further capable of determining an absolute directionality or directional line, with respect to a horizontal plane, along which the target metal object lies.
12 . The device of claim 1 , wherein the device is capable of detecting non-magnetic metal objects.
13 . The device of claim 1 , further comprising at least one magnet capable of magnetizing a metal object in situ.
14 . The device of claim 1 , further comprising a modulator capable of adjusting the sensitivity of the at least one magnetometer.
15 . A method of calibrating a magnetometer-based metal detection device to achieve rotational invariance, the device having at least one sensor capable of sensing a magnetic field in three orthogonal axes, the method comprising the steps of:
collecting raw magnetic field data from each axis of at least one magnetometer sensor having three orthogonal axes;
determining best-fit parameters for an ellipsoid surface;
calculating a transformation matrix that transforms the general ellipsoid surface into a spherical surface;
applying the transformation matrix to the collected raw magnetic field data to determine calibrated magnetic field data values; and
calculating a rotationally invariant magnitude of the magnetic field based on the calibrated magnetic field data values.
16 . The method of claim 15 , wherein determining the best-fit parameters for an ellipsoid surface comprises applying the equation:
Ax
2
+
By
2
+
Cz
2
+
2
Dxy
+
2
Exz
+
2
Fyz
+
2
Gx
+
2
Hy
+
2
Iz
=
1.
17 . The method of claim 16 , wherein calculating a rotationally invariant magnitude of the magnetic field comprises applying the equation:
B
=
B
x
2
+
B
y
2
+
B
Z
2
;
wherein B is the magnetic field.
18 . A method of determining a directionality or directional line along which a target metal object lies via a magnetometer-based metal detection device having at least one sensor capable of sensing a magnetic field in three orthogonal axes, the method comprising the steps of:
calibrating a magnetometer-based metal detection device to achieve rotational invariance;
obtaining a positive detection of a magnetic field indicative of a target metal object via the magnetometer-based metal detection device;
determining which axis of the three orthogonal axes is sensing an elevated magnetic field level above background; and
equating the axis sensing an elevated magnetic field with the directionality or directional line along which the target metal object lies.
19 . The method of claim 18 , further comprising determining an absolute directionality or directional line, with respect to a horizontal plane, along which the target metal object lies via determination of acceleration vector direction of the at least one sensor.
20 . The method of claim 19 , further comprising determining the direction of maximum magnetic field magnitude with respect to the acceleration vector direction of the at least one sensor.