Online Software Help Manual

Display Legacy Contents

Multiplicative Scatter Correction details

The multiplicative scatter correction has been proposed as method in NIR spectroscopy to correct signals for noise. Light scattering or change in path length for each sample is estimated relative to that of an ideal sample. In principle this estimation should be done on a part of the spectrum which does not contain chemical information, i.e. influenced only by the light scattering. However the regions in the spectrum that hold no chemical information often contain the spectral background where the signal to noise ratio may be poor. In practice the whole spectrum is sometimes used. This can be done provided that chemical differences between the samples are small. Each spectrum is then corrected so that all samples appear to have the same scatter level as the ideal.

For details on how to perform a multiplicative scatter correction, please review the "Commands" chapter.

Standard Normal Variate Correction is another method for noise reduction!
Please review the chapter "Standard Normal variate Correction" for details.

Multiplicative Scatter Correction Algorithm

As an estimate of the ideal sample, we can use for instance the average of the calibration set. Multiplicative scatter correction performs best if an offset correction is carried out first. For each sample:


xi: the ith spectrum of the collection used for calculation.

a, b: For each sample, a and b are estimated by ordinary least-squares regression of spectrum xi versus yAverage over the available wavelengths j.

Each value xij of the corrected spectrum xij (MSC) is calculated as:


xij: the intensity of the ith spectrum and jth wavelength of the collection used for calculation.