Reducing sensor noise in multichannel arrays using oversampled temporal projection and associated systems and methods
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.
1. A multi-channel sensor system, comprising:
a multi-channel sensor configured to obtain spatially oversampled data; and
a computing device communicatively coupled to the multi-channel sensor, the computing device configured to—
(a) receive the spatially oversampled data from the multi-channel sensor;
(b) build a spatial model from the data for essential spatial degrees of freedom;
(c) decompose the data into the underlying spatial model to obtain associated amplitude components containing a mixture of original temporal waveforms of the data;
(d) for each channel of the multi-channel sensor, estimate time-domain amplitude components using cross-validation;
(e) for each channel, based on the estimated time-domain amplitude components, identify sensor noise and/or artifacts for that channel; and
(f) for each channel, suppress the identified sensor noise and/or artifacts from the data,
wherein the computing device is configured to estimate the time-domain amplitude components using a cross-validation by applying the spatial model with the channel under investigation excluded from the data and the spatial model, wherein the difference in the temporal domain between the decomposition and the original data for the channel under investigation indicates the sensor noise and/artifacts of the channel under investigation, and
wherein the computing device is further configured to suppress the identified sensor noise and/or artifacts from the data by finding the temporal waveform common to the channel under investigation and the decomposition.
2. The system of claim 1 wherein the multi-channel sensor comprises at least one of: a magnetoencephalographic (MEG) sensor array or an electroencephalographic (EEG) sensor array.
3. The system of claim 1 wherein the computing device is configured to decompose the data into the underlying spatial model by decomposing the data in two situations for each channel of the multi-channel sensor device, the two situations including:
a first situation in which the amplitude components are estimated when applying the spatial model to all channels; and
a second situation in which the amplitude components are estimated when applying the spatial model with the channel under investigation excluded from the data and the spatial model; and
wherein the computing device is further configured to estimate the time-domain amplitude components using cross-validation by comparing, for each channel of the multi-channel sensor device, results of the first situation to results of the second situation in the time domain wherein, for each channel, the difference between the results of the first situation and the results of the second situation indicate the sensor noise and/or artifacts for that channel.
4. The system of claim 1 wherein the data spans a first length of time, and wherein the computing device is further configured to:
divide the data into a plurality of time segments that each span lengths of time shorter than the first length of time; and
perform steps (b)-(f) separately for each time segment.
5. The system of claim 4 , wherein at least some of the time segments are overlapping in time.