Threshold filtering

The Command Threshold calls the Window, shown in fig. 3.14. The threshold level (as a part of the maximal height of the image) may be defined here. In this case the surface regions which are lower than threshold image will be deleted -- their height will be changed to the minimal one on the surface. If the option 2 levels only is selected, then the surface regions higher than threshold level will be changed to the maximal one in this surface.

Figure 3.14: The Window of Threshold Level Selection