Extract an explicit fNIRS physiology frequency band — physiologyBandpass • PhysioNIRS

Applies a zero-phase Butterworth band-pass independently to every source assay column. Band names identify common nuisance ranges; they are not physiological diagnoses.

Usage

physiologyBandpass(
  x,
  assay_name = "OD",
  band = c("mayer", "respiration", "cardiac"),
  range_hz = NULL,
  output_assay = paste0(assay_name, "_", band[[1L]]),
  order = 3L
)

Arguments

x: A governed PhysioExperiment.
assay_name: Exact source assay name.
band: Exactly "mayer", "respiration", or "cardiac".
range_hz: Optional explicit positive passband below Nyquist.
output_assay: Exact name for the added filtered assay.
order: Positive integer Butterworth order.

Value

A clone of x with one zero-phase filtered assay.

Details

Default passbands in Hz are Mayer 0.07--0.13, respiration 0.15--0.40, and cardiac 0.70--2.00. Filtering uses an order-order Butterworth band-pass through signal::filtfilt(). Explicit ranges must remain strictly below the governed Nyquist frequency.

Examples

od <- intensityToOD(PhysioNIRS:::.nirs_demo_object())
# Pass an explicit band; defaults warn that adult ranges may not transfer
filt <- physiologyBandpass(od, band = "cardiac", range_hz = c(0.8, 2))
SummarizedExperiment::assayNames(filt)
#> [1] "raw"        "OD"         "OD_cardiac"