Pqnorm

Purpose

Probabilistic Quotient Normalization for rows of a matrix.

Synopsis

[sx,beta,xref] = pqnorm(x)

[sx,beta,xref] = pqnorm(x,xref)

Description

A robust normalization method similar to Multiplicative Scatter Correction but using the median as the target and a robust fitting of each row to the target. PQN is equivalent to performing a 1-norm on the rows of X, followed by a robust MSC (algorithm = median, see mscorr).

Inputs

• x = Matrix of data to normalize (double).

Optional Inputs

• xref = Reference spectrum to normalize to (used for applying previously calculated normalization target to new data).

Outputs

• sx = Corrected spectra.

• beta = The multiplicative scatter factor/slope.

• xref = The reference spectrum used.

See Also

mscorr, normaliz, snv