data_norm: Normalization and conversion of spectral data

In OpenSpecy: Analyze, Process, Identify, and Share Raman and (FT)IR Spectra

Normalization and conversion of spectral data

Description

adj_res() and conform_res() are helper functions to align wavenumbers in terms of their spectral resolution. adj_neg() converts numeric intensities y < 1 into values >= 1, keeping absolute differences between intensity values by shifting each value by the minimum intensity. make_rel() converts intensities y into relative values between 0 and 1 using the standard normalization equation. If na.rm is TRUE, missing values are removed before the computation proceeds.

Usage

adj_res(x, res = 1, fun = round)

conform_res(x, res = 5)

adj_neg(y, na.rm = FALSE)

mean_replace(y, na.rm = TRUE)

is_empty_vector(x)

Arguments

x	a numeric vector or an R object which is coercible to one by as.vector(x, "numeric"); x should contain the spectral wavenumbers.
res	spectral resolution supplied to fun.
fun	the function to be applied to each element of x; defaults to round() to round to a specific resolution res.
y	a numeric vector containing the spectral intensities.
na.rm	logical. Should missing values be removed?

Details

adj_res() and conform_res() are used in Open Specy to facilitate comparisons of spectra with different resolutions. adj_neg() is used to avoid errors that could arise from log transforming spectra when using adj_intens() and other functions. make_rel() is used to retain the relative height proportions between spectra while avoiding the large numbers that can result from some spectral instruments.

Value

adj_res() and conform_res() return a numeric vector with resolution-conformed wavenumbers. adj_neg() and make_rel() return numeric vectors with the normalized intensity data.

Author(s)

Win Cowger, Zacharias Steinmetz

See Also

min() and round(); adj_intens() for log transformation functions; conform_spec() for conforming wavenumbers of an OpenSpecy object to be matched with a reference library

Examples

adj_res(seq(500, 4000, 4), 5)
conform_res(seq(500, 4000, 4))
adj_neg(c(-1000, -1, 0, 1, 10))
make_rel(c(-1000, -1, 0, 1, 10))

OpenSpecy documentation built on Sept. 14, 2024, 9:07 a.m.