The quantitative measures of surface roughness are extracted

in the spatial frequency domain using the 2D FT. The FT

approach has the desirable properties of noise-immunity,

orientation dependency, and enhancement of periodic features.

The quantitative measures of surface roughness are extracted

in the spatial frequency domain using the 2D FT. The FT

approach has the desirable properties of noise-immunity,

orientation dependency, and enhancement of periodic features.

There is the four year transform, that is a bit slow, but there is also the fast four year transform (FFT) that does the four years within a few seconds ! The noise immunity is new for me, but if noise averages out over four years I assume little is left.