NegativeValuesZeroing: Zeroing of negative values.

In PepsNMR: Pre-process 1H-NMR FID signals

Description

The function sets negative intensities to zero.

Usage

NegativeValuesZeroing(Spectrum_data, verbose = FALSE)

Arguments

Spectrum_data	Matrix containing the spectra in ppm, one row per spectrum.
verbose	If "TRUE", will print processing information.

Details

As explained in BaselineCorrection, negative values does not make sense and can have bad impacts on our statistical analyses. BaselineCorrection do its best to avoid negative intensity values but there might be some remaining.

This filter simply sets them to zero. After the BaselineCorrection they should be close to zero anyway because of the high penalty given to negative values of the signal after the correction.

Value

Spectrum_data

The matrix of spectrums with the negative values set to zero.

Author(s)

Benoît Legat & Manon Martin

References

Martin, M., Legat, B., Leenders, J., Vanwinsberghe, J., Rousseau, R., Boulanger, B., & Govaerts, B. (2018). PepsNMR for 1H NMR metabolomic data pre-processing. Analytica chimica acta, 1019, 1-13.

Rousseau, R. (2011). Statistical contribution to the analysis of metabonomics data in 1H NMR spectroscopy (Doctoral dissertation, PhD thesis. Institut de statistique, biostatistique et sciences actuarielles, Université catholique de Louvain, Belgium).

Examples

require(PepsNMRData)
Nvz.spec <- NegativeValuesZeroing(Data_HS_sp$Spectrum_data_HS_7)

PepsNMR documentation built on Jan. 16, 2021, 2:07 a.m.