analyse_peak_slope: Analyse peak linear slope across NIRS channels

In mnirs: Muscle Near-Infrared Spectroscopy Processing and Analysis

Analyse peak linear slope across NIRS channels

Description

Internal channel-level dispatch for analyse_kinetics(method = "peak_slope"). Computes the maximum local linear slope for each nirs_channel within a single "mnirs" data frame. See analyse_kinetics() for user-facing documentation.

Usage

analyse_peak_slope(
  data,
  nirs_channels = NULL,
  time_channel = NULL,
  start_time = NULL,
  width = NULL,
  span = NULL,
  align = c("centre", "left", "right"),
  direction = c("auto", "positive", "negative"),
  end_window = Inf,
  partial = FALSE,
  na.rm = FALSE,
  verbose = TRUE,
  ...,
  env = rlang::caller_env()
)

Arguments

data	A data frame of class "mnirs" containing time series data and metadata.
nirs_channels	A character vector giving the names of mNIRS columns to operate on. Must match column names in data exactly. If NULL (default), the nirs_channels metadata attribute of data is used.
time_channel	A character string naming the time or sample column. Must match a column name in data exactly. If NULL (default), the time_channel metadata attribute of data is used.
start_time	A numeric value in units of time_channel specifying the response onset (effectively time = 0 of the fit). If NULL (default), retrieves interval_times from "mnirs" metadata, or falls back to 0 or the first positive time value (see Details).
width	An integer defining the local window in number of samples around idx in which to perform the operation, according to align.
span	A numeric value defining the local window time span around idx in which to perform the operation, according to align. In units of time_channel or t.
align	Window alignment as "centre"/"center" (the default), "left", or "right". Where "left" is forward looking, and "right" is backward looking from the current sample.
direction	A character string specifying the response direction "positive", or "negative", or detect with "auto" (default). See Details.
end_window	A numeric value in units of time_channel specifying the window in which to look for the end of the kinetics fit; with no greater/ lesser values within end_window after the first extrema (min/max). end_window = Inf (default) returns the global extreme from the full data range (see Details). For "biexponential", end_window bounds the fast-phase window only, and the default is 30 sec; the full model is then fit to the full data range.
partial	Logical; default is FALSE, only returns values where a full window of valid (non-NA) samples are available. If TRUE, ignores NA and processes available valid samples (see Details).
na.rm	Logical; default is FALSE, propagates any NAs to the returned vector. If TRUE, ignores NAs and processes available valid samples within the local window. May return errors or warnings. (see Details).
verbose	Logical. TRUE (default) will display, and FALSE will silence warnings and information messages helpful for troubleshooting. Global default can be set via options(mnirs.verbose = FALSE).
...	Additional arguments.
env	The calling environment or a defused call, used to report errors and warnings as coming from the user-facing function rather than the validator.

Value

A data.frame with one row per nirs_channel and columns nirs_channels, slope, intercept, y, peak_slope_time, idx. Per-channel metadata are attached as attributes:

• "model": a linear regression model object via stats::lm().

• "fitted_data": a named list of per-channel data frames with columns window_idx and fitted.

• "diagnostics": a data.frame with one row per nirs_channel containing model fit diagnostics.

• "channel_args": a data.frame with one row per nirs_channel recording the resolved arguments used.

See Also

analyse_kinetics(), peak_slope()

mnirs documentation built on Sept. 13, 2026, 1:06 a.m.