Standardization of Near-Infrared Spectrometric Instruments

In this paper, two different approaches are studied for the standardization of near-infrared spectrometric instruments. The first is a simple method based on a univariate slope/bias correction of the predicted values. The second approach proposed is the much more sophisticated piecewise direct standardization (PDS) based on a multivariate correction of spectra. Both standardization methods are applied to three different data sets, and the results obtained are compared. In certain cases, the simple slope/bias correction approach yields results at least as good as those obtained by the PDS procedure. In other cases, the complex PDS procedure is required to obtain acceptable results. A diagnostic tool is developed in order to decide whether the simple slope/bias correction approach can be applied instead of PDS.