snv {rchemo}

Standard normal variate transformation (SNV)

Description

SNV transformation of the row observations (e.g. spectra) of a dataset. By default, each observation is centered on its mean and divided by its standard deviation.

Usage

snv(X, center = TRUE, scale = TRUE)

Arguments

X

X-data (n, p).

center

Logical. If TRUE (default), the centering in the SNV is done.

scale

Logical. If TRUE (default), the scaling in the SNV is done.

Value

A matrix of the transformed data.

Examples

data(cassav)

X <- cassav$Xtest

Xp <- snv(X)

oldpar <- par(mfrow = c(1, 1))
par(mfrow = c(1, 2))
plotsp(X, main = "Signal")
plotsp(Xp, main = "Corrected signal")
abline(h = 0, lty = 2, col = "grey")
par(oldpar)