===== Threshold filter =====
This feature is designed for sorting of points by height. In FemtoScan, filtering based on a single threshold is implemented.

To call up a threshold filter, select it from [[меню_математика|menu Mathematics]] or click on the button

{{:en:processing:Th_1.jpg|}}.

In this case, a dialog box, where you can set the threshold level (as a fraction of the maximum image height) and determine how the points that appear above and below this level will be processed, will appear.

{{:en:processing:Th_2.jpg |}} If a tick is put against field **Set above**, all points with height exceeding the threshold will be set to a value equal to the maximum height of the surface or the height of the threshold, depending on the selected parameter value. Similarly, if a tick is put against field **Set below**, the points that were initially below the threshold will have a minimum or threshold value. If no tick is put against any of these two options (for example, against **Set above**), these points will not be changed.