gamma (version 1.1.0)

peaks_find: Find Peaks

Description

Finds local maxima in sequential data.

Usage

peaks_find(object, ...)
# S4 method for GammaSpectrum
peaks_find(object, method = c("MAD"), SNR = 2, span = NULL, ...)

Value

A PeakPosition object.

Arguments

object

A GammaSpectrum object.

...

Extra parameters to be passed to internal methods.

method

A character string specifying the method to be used for background noise estimation (see below).

SNR

An integer giving the signal-to-noise-ratio for peak detection (see below).

span

An integer giving the half window size (in number of channels). If NULL, 5\ window size.

Author

N. Frerebeau

Details

A local maximum has to be the highest one in the given window and has to be higher than \(SNR \times noise\) to be recognized as peak.

The following methods are available for noise estimation:

MAD

Median Absolute Deviation.

See Also

Other signal processing: baseline, peaks_search(), signal_integrate(), signal_slice(), signal_split(), signal_stabilize(), smooth()

Examples

## Import a LaBr spectrum
LaBr_file <- system.file("extdata/LaBr.TKA", package = "gamma")
LaBr_spc <- read(LaBr_file)

## Find peaks by channel
(LaBr_pks <- peaks_find(LaBr_spc)) # Ugly
plot(LaBr_spc, LaBr_pks)

## Search peaks by channel
(LaBr_pks <- peaks_search(LaBr_spc, index = c(86L, 207L, 496L), span = 7))
plot(LaBr_spc, LaBr_pks, split = TRUE)

## Import a BEGe spectrum
BEGe_file <- system.file("extdata/BEGe.CNF", package = "gamma")
BEGe_spc <- read(BEGe_file)

## Search peaks by energy
(BEGe_pks <- peaks_search(BEGe_spc, index = c(47, 63, 911, 1460)))
plot(BEGe_spc, BEGe_pks, split = TRUE)