peakPeaks: Peak picking algorithm
In lhedjazi/mQTL.NMR: Metabolomic Quantitative Trait Locus Mapping for 1H NMR data

Description Usage Arguments Value Author(s) References See Also Examples

Identification of peaks in metabolomic data based on the calculation of smoothed derivates using Savitzky-Golay filter. The peak is identified if derivative crosses zero, i.e. sign(X'(i))>sing(X'(i+1)).

1	peakPeaks(SpSmooth, dpDerivs, Sp)

`SpSmooth`	a vector specifying smoothed spectrum
`dpDerivs`	a vector specifying smoothed derivative of the spectrum
`Sp`	a vector specifying the spectrum of intrest

identified peaks

Lyamine Hedjazi

Veselkov,K. et al (2009) Recursive Segment-Wise Peak Alignment of Biological 1H NMR Spectra for Improved Metabolic Biomarker Recovery, Anal. Chem., 81(1), 56-66.

sgolayDeriv

load_datafiles()
Sp<-t(read.table(phenofile))

## Peak picking
Spectrum<-Sp[1,]
iOrder <- 3
iFrameLen<- 11

SpDerivs<-sgolayDeriv(Spectrum,iOrder,iFrameLen,2)
SpSmooth<-sgolayDeriv(Spectrum,iOrder,iFrameLen,1)
peaks<-peakPeaks(SpSmooth,SpDerivs,Spectrum)