3D (Areal) Filtering
Band Pass Filter
The combination of an S-filter and an L-Filter may be used to establish a bandwidth of spatial wavelengths which are used for analysis.
When the spatial wavelength of the structure to be analyzed is contained between the S-Filter cutoff and the L-filter cutoff, the filter is termed a Band Pass Filter.
The figure below demonstrates the use of a Band Pass Filter which is comprised of an S-Filter to remove short spatial wavelength structures and an L-Filter used to remove the longer spatial wavelength structures. The final surface consists of a band of spatial wavelengths relevant to the application.
As measured surface without filtering consisting of finer spaced features superimposed on longer wavelength components.
Band Pass Filter applied, eliminating long and short spatial wavelengths prior to analysis.