Hilbert transform phase extraction — hilbert

Compute the instantaneous phase time series for all parcels/voxels via the analytic signal (Hilbert transform). Each parcel timeseries is demeaned before transformation.

Usage

hilbert_phases(timeseries)

Arguments

timeseries: Numeric matrix [N × Tmax]. BOLD signal with N parcels as rows and Tmax timepoints as columns.

Value

Numeric matrix [N × Tmax]. Instantaneous phases in radians.

References

Cabral, J. et al. (2017). Cognitive performance in healthy older adults relates to spontaneous switching between states of functional connectivity during rest. Scientific Reports, 7(1), 5135. doi:10.1038/s41598-017-05425-7

Examples

set.seed(1)
ts <- matrix(rnorm(10 * 200), nrow = 10, ncol = 200)
phases <- hilbert_phases(ts)
dim(phases)  # 10 x 200
#> [1]  10 200