A magnetic field generator includes a plurality of conductive windings comprising a first conductive winding arranged in a first plane and a second conductive winding arranged in a second plane that is substantially parallel to the first plane. The plurality of conductive windings are configured to generate, when supplied with a drive current, a first component of a compensation magnetic field. The first component of the compensation magnetic field is configured to actively shield a magnetic field sensing region located between the first conductive winding and the second conductive winding from ambient background magnetic fields along a first axis that is substantially orthogonal to the first plane and the second plane.

A magnetic field measurement system includes a light source that emits a light beam; an optical fiber to transmit the light beam; a variable optical attenuator to increase stability of an intensity of the light beam; a beam splitter to divide the light beam into an OPM light beam and a monitor light beam; a monitor detector to detect the monitor light beam and generate a monitor signal; a vapor cell with alkali metal atoms disposed therein and configured for transmission of the OPM light beam through the vapor cell; an OPM detector to detect the OPM light beam after transmission through the vapor cell and generate an OPM signal; and a group delay filter to combine the monitor signal and the OPM signal to generate a reduced noise OPM signal, where the group delay filter accounts for a phase difference between the monitor signal and the OPM signal.

A magnetic field measurement system includes a light source that emits a light beam; an optical fiber to transmit the light beam; a variable optical attenuator to increase stability of an intensity of the light beam; a beam splitter to divide the light beam into an OPM light beam and a monitor light beam; a monitor detector to detect the monitor light beam and generate a monitor signal; a vapor cell with alkali metal atoms disposed therein and configured for transmission of the OPM light beam through the vapor cell; an OPM detector to detect the OPM light beam after transmission through the vapor cell and generate an OPM signal; and a group delay filter to combine the monitor signal and the OPM signal to generate a reduced noise OPM signal, where the group delay filter accounts for a phase difference between the monitor signal and the OPM signal.

In a magnetic field measurement apparatus, a light source irradiates a gas cell with linearly polarized light serving as pump light and probe light in a Z axis direction, and a magnetic field generator applies, to the gas cell, a magnetic field A.sub.x which is a time function f(t) having the amplitude A.sub.0 taking n fixed values f.sub.i (where i=1, . . . , and n), and a magnetic field A.sub.y which is a time function g(t) having the amplitude A.sub.0 taking m fixed values g.sub.j (where j=1, . . . , and m) in each of X axis and Y axis directions. A calculation controller calculates a magnetic field C (C.sub.x, C.sub.y, C.sub.z) of a measurement region using the X axis and Y axis components A.sub.x and A.sub.y of an artificial magnetic field A, and a spin polarization degree M.sub.x corresponding to a measurement value W.sub.? from a magnetic sensor.

The invention is directed to a system and methods of capturing rapid changes in complex systems by examining the interaction of the various components within the system. This may be accomplished by decomposing a multivariate signal into a dictionary of elements and a corresponding sparse mixing matrix. Each dictionary element may provide a rank-1 estimation of a disjoint partition of time points of the signal that may permit estimation of the covariance of each partition using an outer-product of the corresponding dictionary element.

Examples described herein may predict therapy efficacy and/or therapeutic parameters using a comparison of individual patient status data and brain network response maps for the therapy. For example, VNS parameters may be predicted using a comparison of patient EEG data and brain network response maps of VNS therapy at various parameters.

A method of using a magnetometer system (30) to analyse the magnetic field of a region of a subject's body is provided. The method comprises using one or more detectors (60) to detect the time varying magnetic field of a region of a subject's body, using a digitiser (42) to digitise a signal or signals from the one or more detectors (60), each signal that is digitised including noise and a periodic signal produced by one or more of the one or more detectors (60) due to the time varying magnetic field of the region of the subject's body, and averaging the digitised signal or signals over plural periods. The magnetometer system (30) is configured such that the noise in each signal provided to the digitiser for digitisation is greater than about 25% of the interval between digitisation levels of the digitiser (42).

A method for characterizing a brain electrical signal comprising forming a temporo-spectral decomposition of the signal to form a plurality of time resolved frequency signal values, associating each instance of the signal value with a predetermined function approximating a neurological signal to form a table of coefficients collectively representative of the brain electrical signal.

Two types of information processing devices includes circuitry to display, on a display device, a position representation area indicating a position of each of a group of sensors that detects biomedical signals of a test subject, display on the display device a selection acceptance area accepting selection of a plurality of positions of a plurality of desired sensors, the plurality of positions being selected from the group of sensors using an operating unit, and display on the display device a waveform display area displaying a waveform output from the plurality of desired sensors corresponding to the plurality of selected positions. In the first type of information processing device, single-region data indicating a region including the plurality of selected positions is displayed in the position representation area. In the second type of information processing device, the plurality of selected positions are enlarged and displayed in the position representation area.

A method for suppressing sensor noise in a spatially oversampled sensor array includes receiving spatially oversampled multi-channel sensor data from a region of interest and building a spatial model from the data for essential spatial degrees of freedom. The method further includes decomposing the data into the underlying spatial model to obtain associated amplitude components containing a mixture of original temporal waveforms of the data and, for each channel of the multi-channel sensor, estimating time-domain amplitude components using cross-validation. Next, for each channel, based on the estimated time-domain amplitude components, sensor noise and/or artifacts for that channel are identified. Finally, for each channel, the identified sensor noise and/or artifacts can be suppressed from the data.