Fig. 3.

Calculation of the overlap coefficient for (a) unprocessed synthetic spectra and (b) preprocessed synthetic spectra. In the unprocessed spectra, large nontissue-specific variations in the spectra are visible, which make it difficult to distinguish tissue 1 (red lines) from tissue 2 (blue lines). In the processed spectra, the nontissue-specific variations are reduced significantly. (c), (d) To calculate the overlap coefficient per wavelength histograms of the reflectance values at a single wavelength are created. The overlap coefficient is equal to the number of reflectance values in the intersection of the two sets (purple bars), divided by the number of reflectance values in the smallest set [Eq. (20)]. (e), (f) The mean overlap coefficient over all wavelengths is calculated (dashed red line). This shows that the unprocessed spectra have a high overlap, whereas the processed spectra have a low overlap.