Fig. 7.

Overlap between sets of spectra with different scatter slopes ($b$) for eight preprocessing algorithms. The mean overlap coefficient is shown for five different values of $b$. The unprocessed result is shown in the top left image, here a high overlap due to the nontissue-specific variations can be seen between the different values of $b$. Here, SNV, MSC, and AUC reduce the overlap the most. SW and MM perform comparably with SW reducing the overlap only slightly more. MC, FD, and SD reduce the overlap the least, with SD increasing the overlap.