baseline_polynomial {alkahest}

Polynomial Baseline Estimation

Description

Polynomial Baseline Estimation

Usage

baseline_polynomial(x, y, ...)

## S4 method for signature 'numeric,numeric'
baseline_polynomial(x, y, d = 3, tolerance = 0.001, stop = 100)

## S4 method for signature 'ANY,missing'
baseline_polynomial(x, d = 3, tolerance = 0.001, stop = 100)

Arguments

x, y

A numeric vector. If y is missing, an attempt is made to interpret x in a suitable way (see grDevices::xy.coords()).

...

Currently not used.

d

An integer giving the degree of the polynomial. Must be less than the number of unique points.

tolerance

A numeric scalar giving the tolerance of difference between iterations.

stop

An integer giving the stopping rule (i.e. maximum number of iterations).

Value

Returns a list with two components x and y.

Author(s)

N. Frerebeau

References

Lieber, C. A. and Mahadevan-Jansen, A. (2003). Automated Method for Subtraction of Fluorescence from Biological Raman Spectra. Applied Spectroscopy, 57(11): 1363-67. doi:10.1366/000370203322554518.

See Also

signal_correct()

Other baseline estimation methods: baseline_asls(), baseline_linear(), baseline_peakfilling(), baseline_rollingball(), baseline_rubberband(), baseline_snip()

Examples

## X-ray diffraction
data("XRD")

## Subset from 20 to 70 degrees
XRD <- signal_select(XRD, from = 20, to = 70)

## Plot spectrum
plot(XRD, type = "l", xlab = expression(2*theta), ylab = "Count")

## Polynomial baseline
baseline <- baseline_polynomial(XRD, d = 4, tolerance = 0.02, stop = 1000)

plot(XRD, type = "l", xlab = expression(2*theta), ylab = "Count")
lines(baseline, type = "l", col = "red")