rescale_mnirs: Re-scale data range

In mnirs: Muscle Near-Infrared Spectroscopy Processing and Analysis

Re-scale data range

Description

Expand or reduce the range (min and max values) of data channels to a new amplitude/dynamic range, e.g. re-scale the range of NIRS data to c(0, 100).

Usage

rescale_mnirs(
  data,
  nirs_channels = list(),
  range,
  verbose = TRUE
)

Arguments

data	A data frame of class "mnirs" containing time series data and metadata.
nirs_channels	A list() of character vectors indicating grouping structure of mNIRS channel names to operate on (see Details). Must match column names in data exactly. Retrieved from metadata if not defined explicitly. list("A", "B", "C") Will operate on each channel independently, losing the relative scaling between channels. list(c("A", "B", "C")) Will operate on all channels together, preserving the relative scaling between channels. list(c("A", "B"), c("C", "D")) Will operate on channels A & B in one group, and C & D in another group, preserving relative scaling within, but not between groups.
range	A numeric vector in the form c(min, max), indicating the range of output values to which data channels will be re-scaled.
verbose	Logical. Default is TRUE. Display or silence (if FALSE) warnings and information messages helpful for troubleshooting. Ad global default can be set via options(mnirs.verbose = FALSE).

Details

nirs_channels = list() can be used to group data channels (column names) to preserve absolute or relative scaling.

• Channels grouped together in a vector (e.g. list(c("A", "B"))) will be re-scaled to a common range, and the relative scaling within that group will be preserved.

• Channels in separate list vectors (e.g. list("A", "B")) will be re-scaled independently, and relative scaling between groups will be lost.

• A single vector of channel names (e.g. c("A", "B")) will group channels together.

• Channels (columns) in data not explicitly defined in nirs_channels will be passed through untouched to the output data frame.

nirs_channels can be retrieved automatically from data of class "mnirs" which has been processed with {mnirs}, if not defined explicitly. This will default to returning all nirs_channels grouped together, and should be defined explicitly for other grouping arrangements.

Value

A tibble of class "mnirs" with metadata available with attributes().

Examples

## read example data
data <- read_mnirs(
    file_path = example_mnirs("moxy_ramp"),
    nirs_channels = c(smo2_left = "SmO2 Live",
                      smo2_right = "SmO2 Live(2)"),
    time_channel = c(time = "hh:mm:ss"),
    verbose = FALSE
) |>
    rescale_mnirs(        ## un-grouped nirs channels to rescale separately 
        nirs_channels = list(smo2_left, smo2_right), 
        range = c(0, 100) ## rescale to a 0-100% functional exercise range
    )

data


    if (requireNamespace("ggplot2", quietly = TRUE)) {
        plot(data, time_labels = TRUE) +
            ggplot2::geom_hline(yintercept = c(0, 100), linetype = "dotted")
    }

mnirs documentation built on May 15, 2026, 9:07 a.m.