Spectral mixture analysis: Linear combination of spectra — linear

Use linear regression resp. non negative linear regression (package nnls) without intercept to estimate coefficients for a linear combination of reference spectra to represent one or multiple target spectra. For a sparse solution and/or correlated references see omp.

linear_combination(
  targets,
  references,
  references_ids = NULL,
  nonnegative = FALSE
)

Arguments

targets	a hyperSpec object.
references	a hyperSpec object containing the spectra to be combined in in a linear manner.
references_ids	either a single string or numeric specifying the column with names for the references in the object `references`, or a character vector with a name per reference spectrum.
nonnegative	logical; set TRUE to restrict coefficients to be positive.

Value

a list containing the following members:

coefficients: coefficient matrix
basis: the references object as supplied
fit: the return value of the multivariate call to `stats::lm()` or a list of return values of the outputs of `nnls::nnls()` for each target spectrum.