Related versions of the multiplicative scatter correction method for preprocessing spectroscopic data

Various multiplicative transformations of spectral variables have been used with some success as preprocessing methods for diffuse near-infrared spectroscopy data. We discuss first which additive/multiplicative transformations conserve the area under the spectral curve. Next we look at the relationship between the Multiplicative Scatter and the Standard Normal Variate transformations, and use a minimizing norm formulation to isolate three specific transformations that seem to be singled out as particularly interesting. In an empirical investigation using 8 different data sets, each with several constituents, the different transformation methods are compared.