90results about "Stray field compensation" patented technology

A method for extracting information about one or more magnetic sources includes obtaining a first plurality of signals corresponding to magnetic sensor data generated by one or more magnetometers in an unshielded environment at a first time; receiving second information of a direction and a magnitude of a first known magnetic field applied to the one or more magnetometer, the first plurality of signals is acquired while the first known magnetic field is applied and wherein the first known magnetic field encodes directional information of the one or more magnetic sources into the first plurality of signals; extracting the information comprising three-dimensional spatial information of the one or more magnetic sources, respective orientations and strengths of the one or more magnetic sources based on the first information, the second information, and the plurality of signals corresponding to the magnetic sensor data.

A probe for locating a magnetic marker for use in surgery. The probe comprises at least two first coils (3a, 3b) and at least one second coil (5) which are arranged substantially coaxially on a longitudinal axis of the probe for measuring the proximity of a magnetic marker to the probe, and a baseline voltage taring device (7) comprising a first elongate conductor which defines a conducting path extending partially around the probe axis. The conducting path is configured and arranged such that in use the balancing magnetic field induces a balancing voltage in a sense coil that at least partially offsets the baseline voltage. Also disclosed is a method of manufacturing such a probe, a method of setting up such a probe for use in sensing a magnetic marker, and detection apparatus for locating a magnetic marker during surgery.

The present disclosure relates to a method (100) of magnetically calibrating a magnetometer sensing system (30) with respect to an electronic device (50), the method (100) comprising: detecting (110) a disturbing magnetic source (520) in the electronic device (50) relative to a reference coordinate system (X, Y, Z) of the magnetometer sensing system (30); identifying (120) one or more magnetometers (Sk,l) of the magnetometer sensing system (30) which are magnetically affected by the detected disturbing magnetic source (520); selecting (130) one or more balancing magnetic sources (400) to reduce a magnetic effect of the detected disturbing magnetic source (520) on the one or more identified magnetometers (Sk,l); and placing (140) the one or more selected balancing magnetic sources (400) in a fixed relation to the magnetometer sensing system (30) and / or to the disturbing magnetic source (520).

In a magnetic field detection device capable of detecting a weak magnetic field without using a shield room, the number of components is reduced, and the circuit structure is simplified. A magnetic field detection device (1) includes: a cancellation coil (C2) wound around a winding core portion (13) of a bobbin (10); magnetic sensors (S1, S21-S24) fixed to mutually different positions of the bobbin (10); and a feedback circuit (31) that cancels an ambient magnetic field of a cancellation space by causing a cancellation current to flow through the cancellation coil (C2) in accordance with an output signal of the magnetic sensor (S1). The magnetic sensors (S21-S24) are disposed within the cancellation space. In this way, a common cancellation coil (C2) is used for the magnetic sensors (S1, S21-S24), so the number of components can be reduced, and the circuit structure can be simplified.

A method related to magnetic field interference and a sensing system are provided. In the method, magnetic field uniformity within a time period is determined. Movement situation within the time period is determined. Magnetic field interference situation is determined according to the magnetic field uniformity and the movement situation.

A soft magnetic sensor comprising a soft material containing randomly distributed magnetic microparticles and a magnetometer that can estimate force and localize contact over a continuous area. A reference magnetometer can be used to filter motion and ambient noise. Methods for locating contact and determining force comprise data analysis of the magnetometer output. In some embodiments, the sensor can localize an object prior to contact.

Various embodiments disclosed herein comprise a system. The system comprises a coil, a magnetic field sensor, and a controller. The coil generates a spatially and temporally varying magnetic field. The magnetic field sensor measures the magnetic field and a background magnetic field. The magnetic field sensor provides a magnetic field measurement and a background magnetic field measurement to the controller. The controller determines the position and orientation of the magnetic field sensor based on the magnetic field measurement and the background magnetic field measurement. The controller transfers control signaling to modify the magnetic field based on the position and orientation of the magnetic field sensor to null the background magnetic field. The coil receives the control signaling and modifies the spatially and temporally varying magnetic field based on the control signaling to null the background magnetic field.

The present invention relates to a method for determining the coupling between magnetometers in an array of N magnetometers (e.g., by means of an optically pumped magnetometer), wherein each magnetometer includes a field cancellation system that can be enabled to operate the magnetometer in a zero field. The method includes a first phase (P1), in which the N magnetometers are divided into N - 1 magnetometers with the field cancellation system deactivated and one measuring magnetometer with the field cancellation system activated. The first phase includes: - generating (GENj) by these magnetometers a plurality of reference magnetic fields with known amplitudes and different directions, - measuring (MESi) by the measuring magnetometer the ambient magnetic field on a plurality of measurement axes, - determining (CALCij) the coupling coefficient between the measuring magnetometer and each of the N magnetometers based on the measured values and these known amplitudes.

A probe for locating magnetic markers used in surgery. The probe includes: at least two first coils (3a, 3b) and at least one second coil (5), which are arranged substantially coaxially on the longitudinal axis of the probe for measuring the proximity of the magnetic marker to the probe; and a reference voltage balancing device (7) comprising a first elongated conductor defining a conductive path extending partially around the probe axis. The conductive path is configured and arranged such that, in use, a balancing magnetic field induces a balancing voltage in the sensing coil that at least partially cancels out the reference voltage. Methods for manufacturing such a probe, methods for setting such a probe for sensing magnetic markers, and detection devices for locating magnetic markers during surgery are also disclosed.

A three-axis magnetic field detection device includes a magnetic field conversion unit for generating a stray field having a magnetic field direction according to a magnetic field direction of an outer magnetic field using magnetic particles, a magnetic field measurement unit for measuring a magnetic field direction with respect to an X-axis magnetic field and Y-axis magnetic field in relation to the outer magnetic field, and a magnetic field detection unit for detecting the X-axis magnetic field, the Y-axis magnetic field and the Z-axis magnetic field based on the stray field and the measured magnetic field direction.

A probe (303; 403) for sensing a magnetic marker, comprising a first coil set (313; 413) including a first coil of a first coil type, e.g., a sense coil (305; 405), disposed between a first pair of coils of a second coil type, e.g., a drive coil (301a, 301b; 401a, 401b) connected in series, and a balance element (317; 417) axially spaced from the first coil set (313; 413) along the length of the probe (303; 403). The balance element (317; 417) is configured or arranged to generate a sense voltage that fully offsets, partially offsets, or minimizes a sense voltage induced in one or more sense coils (305; 405) of the first coil set from the drive coil or coils (301a, 301b; 401a, 401b). A detection system is also disclosed, comprising the probe (303; 403), a magnetic field generator configured to drive an alternating magnetic field through the drive coils (301a, 301b; 401a, 401b) of the first coil set and the balance element (317; 417), and at least one detector configured to receive a signal indicative of a sensed voltage.

The invention relates to a magnetoresistive sensor (500). A magnetoresistive sensor (500) includes a layer stack (510) having at least one reference layer (512) having a reference magnetization perpendicular to a plane of the layer stack and at least one free layer (516) having a vortex magnetization. The magnetoresistive sensor (500) further comprises at least one soft magnetic shield (520) arranged adjacent to the layer stack, which soft magnetic shield is designed to reduce the influence of an external magnetic field on the free layer (516) along the shield axis (530).

A magnetoresistive sensor includes a layer stack containing at least one reference layer having a reference magnetization perpendicular to the plane of the layer stack and at least one free layer having a vortex magnetization. The magnetoresistive sensor furthermore includes at least one soft-magnetic shield arranged adjacent to the layer stack and configured to reduce an influence of an external magnetic field along a shielding axis on the free layer.

The application discloses an aviation magnetic interference suppression method, device and equipment based on double-machine multi-magnetic sensors, wherein two magnetic sensors are arranged on two magnetic exploration airplanes respectively, the two magnetic exploration airplanes are located at the same height, and the height difference between any one of the magnetic exploration airplanes and a position of a detection target is h; the two magnetic exploration airplanes are apart from each other by L; the detection distances of the two magnetic exploration airplanes are both R; it can be guaranteed that the two magnetic exploration airplanes cannot measure the target signal at the same time, so that only one of the common-mode magnetic signals of the magnetic exploration airplanes contains the target signal and the diurnal magnetic interference signal, and the common-mode signal of the other magnetic exploration airplane contains only the diurnal magnetic interference signal; the target signal after the diurnal magnetic interference signal is removed can be obtained by subtracting the common-mode signals of the two magnetic exploration airplanes; and the diurnal magnetic interference signal can be better suppressed through the method, so that the accuracy of the target signal is improved.

Methods, apparatuses, and systems for detecting a stray magnetic field are provided. An example apparatus may include a first magnetic sensor element at a first position relative to a magnetic field source to detect a target magnetic field emitted by the magnetic field source, a second magnetic sensor element at a second position relative to the magnetic field source to detect the target magnetic field emitted by the magnetic field source, and a processor element electronically coupled to the first magnetic sensor element and the second magnetic sensor element. In some examples, the processor element may be configured to: receive a first output from the first magnetic sensor element, receive a second output from the second magnetic sensor element, and detect the stray magnetic field interfering with the target magnetic field based at least in part on the first output and the second output.

The present invention discloses a dual Helmholtz control device for dynamic magnetic field compensation, comprising: a reverse Helmholtz coil, a forward Helmholtz coil, a fluxgate sensor, a uniform field compensation module, and a gradient compensation module; the reverse Helmholtz coil and the forward Helmholtz coil are parallel and opposite to each other, and are used to generate an induced magnetic field; the fluxgate sensor is used to convert the magnetic induction intensity of the induced magnetic field into a voltage signal; the uniform field compensation module is used to provide a gradient magnetic field for the reverse Helmholtz coil to cancel the non-uniform term in the geomagnetic field; the gradient compensation module is used to make the forward Helmholtz coil generate a corresponding bias uniform magnetic field to cancel the uniform term in the geomagnetic field. The dual Helmholtz coil structure adopted by the present invention compensates the uniform term and the non-uniform term in the geomagnetic field while reducing the size of the shielding device, and can provide an extremely weak magnetic environment with a large uniform area.

A method of diagnosing internal characteristics of a device includes applying a strong magnetic field to the device. The method can include reducing the strong magnetic field at a location of one or more sensors. At least one of the one or more sensors is proximate to the device. The method can include measuring induced magnetic fields around the device. The method can include measuring induced or intrinsic electrical current flow. The method can include measuring intrinsic magnetic properties. The induced magnetic fields can include diagnostic information on properties of the device and how the properties change over time. The device may be, for example, a battery, a capacitor, a supercapacitor, or a fuel cell. The presented measurement of magnetic susceptibility can be performed on materials, solutions, chemical substances, or tissue samples.

Influence of RF noise and external magnetic field on the image quality of a portable magnetic resonance imaging (MRI) system (1) are to be avoided. This is achieved by providing a system and a computer-implemented method for determining an optimized position and / or orientation of a portable MRI system (1) for an MR imaging process in a medical environment (2), comprising at least one RF noise sensor (3), wherein the RF noise sensor (3) is configured for measuring RF noise in the medical environment (2) and to provide sensor data, at least one magnetic field sensor (4), wherein the magnetic field sensor (4) is configured to measure the external magnetic field in the medical environment (2) and to provide sensor data, a processor unit (5), wherein the sensors (3, 4) are connected to the processor unit (5), the processor unit (5) comprising at least one memory (6) for storing instructions, at least one processor (7) configured to execute the instructions to cause the following to be performed: measuring RF noise and the external magnetic field in the medical environment by means of corresponding sensors (3, 4), evaluating the sensor data and creating spatial distributions of the measured RF noise and / or the measured external magnetic field in the medical environment (2), determining a position and / or orientation of the portable MRI system (1) in the medical environment (2) for an MR imaging process based on the spatial distributions of the measured RF noise and / or the measured external magnetic field.

An unmanned aerial vehicle (UAV) 100 carries an optically pumped magnetometer 110 for detecting a signal from a magnetic beacon. The UAV has one or more rotors 106 which produce a noise signal. The ma

A magnetoresistive sensor (500) is proposed. The magnetoresistive sensor (500) comprises a layer stack (510) with at least one reference layer (512) having a reference magnetization perpendicular to the plane of the layer stack and at least one free layer (516) with a vortex magnetization. The magnetoresistive sensor (500) further comprises at least one soft magnetic shield (520) arranged adjacent to the layer stack, which is configured to reduce the influence of an external magnetic field along a shielding axis (530) on the free layer (516).

To avoid the influence of RF noise and external magnetic fields on the image quality of a portable magnetic resonance imaging (MRI) system (1). This is accomplished by providing a system and a computer-implemented method for determining an optimized position and / or orientation of a portable MRI system (1) for an MR imaging procedure in a medical environment (2), the system comprising: at least one RF noise sensor (3), the RF noise sensor (3) is configured for measuring RF noise in the medical environment (2) and providing sensor data; at least one magnetic field sensor (4), where the magnetic field sensor (4) is configured to measure the external magnetic field in the medical environment (2) and to provide sensor data; a processor unit (5) wherein the sensors (3, 4) are connected to the processor unit (5), the processor unit (5) comprising at least one memory (6) for storing instructions and at least one processor (7), the at least one processor is configured to execute the instructions such that the following are performed: measuring RF noise in the medical environment and the external magnetic field by means of a corresponding sensor (3, 4), evaluating the sensor data and creating a spatial distribution of the measured RF noise and / or the measured external magnetic field in the medical environment (2), a position and / or orientation of the portable MRI system (1) for an MR imaging procedure in the medical environment (2) is determined based on the measured RF noise and / or the spatial distribution of the measured external magnetic field.

The invention refers to a kit for generating a predetermined magnetic field distribution in a predetermined volume in relation to a device, comprising: a plurality of sensor-source units configured to be placed around the device, wherein each sensor-source unit includes a magnetic field generating element for generating a respective magnetic field in the volume, the respective magnetic field being configured to contribute to the predetermined magnetic field distribution generated by the kit, a magnetic field sensing element for sensing the magnetic field at a surface of the volume, and a bracket to which the magnetic field generating element and the magnetic field sensing element are fixedly attached.

An apparatus comprises one or more substrates and one or more coils. At least one of the coils is configured to produce a first magnetic field that induces eddy currents in a conductive target, which generates a reflected magnetic field. One or more magnetic field sensing elements supported by the one or more substrates detect the reflected magnetic field. A conductive support structure supports the one or more substrates. The support structure includes a gap in an area adjacent to the one or more coils so that the support structure does not generate a reflected magnetic field in response to the first magnetic field.

A magnetic field sensor according to the present invention comprises: a first element having a resistance value that changes in response to a magnetic field; a first readout circuit that outputs a first voltage corresponding to the resistance value of the first element; a second element having a resistance value that changes in response to a magnetic field; a second readout circuit that outputs a second voltage corresponding to the resistance value of the second element; wiring provided for the first element and the second element; and a control circuit that controls the current flowing through the wiring on the basis of the first voltage. The ratio of the amount of change in the first voltage with respect to the amount of change in the magnetic field and the ratio of the amount of change in the second voltage with respect to the amount of change in the magnetic field are different from each other.

Disclosed herein is a magnetic field detection system that includes a shield box having a magnetic shield surrounding a measurement space, a magnetic sensor provided in the measurement space and fixed to the shield box, a sample stage at least a part of which is inserted into the measurement space, a table fixed to the sample stage and on which a sample is placed, and a drive mechanism configured to change a position of the sample stage. The table has a protruding part protruding from the sample stage without overlapping the sample stage. At least the protruding part of the table is constituted by a material positioned at a more positive side in a triboelectric series than a material constituting the sample stage.

A method of reducing a transmit back-EMF decay period of a pulse induction metal detector, the method comprising: connecting a diode to a first inductive winding within a coil housing, the inductive winding at least for transmitting a magnetic field; wherein the pulse induction metal detector is arranged and configured such that the diode is forward biased during some of the transmit back-EMF period, and the diode is reverse biased during non-transmit periods of the inductive winding, the non-transmit periods comprise a period to process a receive signal of the pulse induction metal detector.