On the Scales Associated with Near-Infrared Reflectance Difference Spectra

Abstract

Scale differences of individual near-infrared spectra are identified when set-independent standard normal variate (SNV) and de-trend (DT) transformations are applied in either SNV followed by DT or DT then SNV order. The relationship of set-dependent multiplicative scatter correction (MSC) to SNV is also referred to. A simple correction factor is proposed to convert derived spectra from one order to the other. It is suggested that the suitable order for the study of changes using difference spectra (when removing baselines) should be DT followed by SNV, which leads to all derived spectra on the scale of mean zero and variance equal to one. If baselines are identical, then SNV scale spectra can be used to calculate differences.

Use of near infrared hyperspectral tools for the screening of extractable polyphenols in red grape skins

“…Scattering effects were removed using multiplicative scatter correction (MSC), standard normal variate (SNV), and detrending (Dhanoa, Lister, & Barnes, 1995;Geladi, MacDougall, & Martens, 1985). Moreover, the effect of differentiation and variations in spectral ranges were tested in the development of the NIRS calibrations.…”

The mineral composition (Ca, P, Mg, K, Na) in cheeses (cow’s, ewe’s and goat’s) with different ripening times using near infrared spectroscopy with a fibre-optic probe

“…In all cases, cross-validation was performed by splitting the population into four groups. The effects of scattering were removed using MSC (Multiplicative Scatter Correction), SNV (Standard Normal Variate), DT (DeTrend) or SNV-DT, (Dhanoa, Lister, & Barnes, 1995). Moreover, the mathematical treatments were tested in the development of the NIRS calibrations.…”

Prediction of sensory attributes of cheese by near-infrared spectroscopy

“…Spectra were centred but not scaled before pretreatment and calibration. Spectra were pre-treated by different techniques, including multiplicative scatter correction (MSC), standard normal variate (SNV), DT (DeTrend) or SNV-DT (Dhanoa, Sister, & Barnes, 1995). This treatment allows the minimising of the scattering effect, since mainly the shift of the maximum and the width changes of the spectra were considered.…”