cwt: Continuous Wavelet Transform (CWT) In MassSpecWavelet: Mass spectrum processing by wavelet-based algorithms

Description

CWT(Continuous Wavelet Transform) with Mexican Hat wavelet (by default) to match the peaks in Mass Spectrometry spectrum

Usage

 1 cwt(ms, scales = 1, wavelet = "mexh")

Arguments

 ms Mass Spectrometry spectrum (a vector of MS intensities) scales a vector represents the scales at which to perform CWT. wavelet The wavelet base, Mexican Hat by default. User can provide wavelet Psi(x) as a form of two row matrix. The first row is the x value, and the second row is Psi(x) corresponding to x.

Value

The return is the 2-D CWT coefficient matrix, with column names as the scale. Each column is the CWT coefficients at that scale.

Author(s)

Pan Du, Simon Lin

Examples

 1 2 3 4 5 6 7 8 9 10 data(exampleMS) scales <- seq(1, 64, 3) wCoefs <- cwt(exampleMS[5000:11000], scales=scales, wavelet='mexh') ## Plot the 2-D CWT coefficients as image (It may take a while!) xTickInterval <- 1000 image(5000:11000, scales, wCoefs, col=terrain.colors(256), axes=FALSE, xlab='m/z index', ylab='CWT coefficient scale', main='CWT coefficients') axis(1, at=seq(5000, 11000, by=xTickInterval)) axis(2, at=c(1, seq(10, 64, by=10))) box()

Example output 