Fourier Filtering

The Fourier Filter is used for enhancing or reducing certain structures by modifying the associated Fourier components. There are often situations where it can be an advantage to apply a Fourier filter:

• Reduction of noise or other undesired elements

• Visual enhancement of certain structures

• In combination with Roughness analysis where you may want to measure the roughness within a certain band

• To limit the unit cell detection range

The Fourier Filter tab menu contains two sub menus:

Band Filtering (Concentric Fourier Filtering), which by a few parameter settings can be used to perform:

• Low-pass filtering,

• High-pass filtering,

• Band-pass filtering

• Band-reject filtering,

• Band-width filtering

Selective Filtering, where the user interactively can remove selected Fourier components which can be selected by:

The circle, rectangle and oblique marker tools

The color scale markers or the associated Threshold Fourier Filtering scroll bars in the Fourier Dialog is applied for selection of Fourier components exceeding certain upper or lower values.