Spectra are superimposed in spectroscopy of stray light effects in the range close to infra-red, which occur primarily as a result of the changed layering of sample particles on the glass surface of the measuring cell. If the sample is filled twice into a vessel and measured, the spectra will frequently differ due to a parallel displacement without any substance causes being present.
|Transformation of spectra|
In order to correct these undesirable effects in spectra (scatter correction) and to emphasise the differences between spectra of different samples incurred by the contents, several processes have been developed which are of significance in spectroscopy in the near-infrared.
The following examples are represented on the one hand in model spectra of simple bands, in order to make the effect of the transformation clear. On the other hand, transformed spectra and the effects of transformation on the connection between absorption at 1930 nm and moisture content of rape samples are reproduced.
In Figure 1 the untransformed rape spectra are shown, on the basis of which the different processes of spectrum transformation are represented.
|Figure 1 Original spectra (log 1/R) of rape samples of|
different moisture contents
|Figure 2 XY graphic of absorption at 1930-nm and the moisture content|
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