baselines: Polynomial Baseline Fitting These functions fit polynomal...

In hyperSpec: Work with Hyperspectral Data, i.e. Spectra + Meta Information (Spatial, Time, Concentration, ...)

Description

Both functions fit polynomials to be used as baselines. If apply.to is NULL, a hyperSpec object with the polynomial coefficients is returned, otherwise the polynomials are evaluated on the spectral range of apply.to.

spc.fit.poly.below tries to fit the baseline on appropriate spectral ranges of the spectra in fit.to. For details, see the vignette ("baseline").

Usage

spc.fit.poly(fit.to, apply.to = NULL, poly.order = 1)

spc.fit.poly.below(fit.to, apply.to = fit.to, poly.order = 1,
  npts.min = NULL, noise = 0)

Arguments

fit.to	hyperSpec object on which the baselines are fitted
apply.to	hyperSpec object on which the baselines are evaluted If NULL, a hyperSpec object containing the polynomial coefficients rather than evaluted baselines is returned.
poly.order	order of the polynomial to be used
npts.min	minmal number of points used for fitting the polynomial
noise	noise level to be considered during the fit. It may be given as one value for all the spectra, or for each spectrum separately.

Details

spc.fit.poly calculates the least squares fit of order poly.order to the complete spectra given in fit.to. Thus fit.to needs to be cut appropriately.

Value

hyperspec object containing the baselines in the spectra matrix, either as polynomial coefficients or as polynomials evaluted on the spectral range of apply.to

Author(s)

C. Beleites

See Also

vignette ("baseline", package = "hyperSpec")

Examples

## Not run: vignette ("baseline", package = "hyperSpec")

spc <- chondro [1 : 10]
baselines <- spc.fit.poly(spc [,, c (625 ~ 640, 1785 ~ 1800)], spc)
plot(spc - baselines)
baselines <- spc.fit.poly.below (spc)
plot (spc - baselines)

Example output

Loading required package: lattice
Loading required package: grid
Loading required package: ggplot2
Package hyperSpec, version 0.98-20161118

To get started, try
   vignette ("introduction", package = "hyperSpec")
   package?hyperSpec 
   vignette (package = "hyperSpec")

If you use this package please cite it appropriately.
   citation("hyperSpec")
will give you the correct reference.

The project homepage is http://hyperspec.r-forge.r-project.org


Fitting with npts.min =  15 

hyperSpec documentation built on May 2, 2019, 5:45 p.m.