[Question] Pre-processing internal standard

Submitted by miguelG on 25 January 2018 - 6:24pm
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Hello everyone,
Software OPUS has an option to select which pre-processing to use. One of those pre-processings is "Internal Standard".
My question is: does anyone know what kind of pre-processing this is? I mean, the mathematics behind it, because I cannot find anything online related to this pre-processing.
Thanks!