peakPeaks {mQTL.NMR} | R Documentation

## Peak picking algorithm

### Description

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)).

### Usage

    peakPeaks(SpSmooth, dpDerivs, Sp)

### Arguments

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

### Value

identified peaks

### Author(s)

Lyamine Hedjazi

### References

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.

### See Also

`sgolayDeriv`

### Examples

    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)

[Package mQTL.NMR version 1.14.0 Index]