Mazzoni et al. proposed another method. (2007) and named it extended fluorescence detector (eFLD) here. Its spectral resolution is 0.03nm. They estimate that F is in three main absorption bands. This series of black lines appears in a single absorption band with very high resolution, not in the frequency spectrum (see Figure 2). Similar to cFLD and iFLD that we have already described. The main purpose of this method (eFLD) is to reconstruct a single feature (i.e. band) of surface reflectivity in all known absorption lines. For this reason, we assume that in this case, the radiation spectrum of the local maximum is not correspondingly absorbed-not always satisfactory-and is suitable for the local maximum, such as R, to obtain a continuous reflection baseline, according to the following formula:

That's it. A similar assumption is that iFLD is only based on reflection function, and the spectral shape of its f is not determined (specified).