Preprocess: data preprocessing

In the normal mode of operation, the data preprocessing menu shown in Fig. 15 offers three options (the ``expert'' mode has few more choices not described here). The options accessible in normal mode are:

• Limit energy range is used if only a subset of energies of the stack are to be used in the analysis (see Fig. 16).
• Clip to subregion is used if only a subset of the pixels in the stack are to be used.
• Optical density filter is used to filter (zero out) large (and therefore unreliable) optical densities. This option is useful if the stack includes part of a grid bar.

Figure 15: The Preprocess menu gives options for data preprocessing.

Figure 16: By dragging the mouse across an energy region, one can define a limited range.