Detrending as described here is a useful technique used as a preprocessor for the Fast Fourier Transform.
However how can it best be applied in a multidimensional case?
Own work: What I have tried for 2 Dimensional functions is
- Apply detrending in dimension 1
- Apply detrending in dimension 2
- Apply FFT dimension 1
- Apply FFT dimension 2
What happens here is that after step 2 of detrending the detrending done in step 1 can become "scrambled" or "undone" in some sense of the word as a gradient is applied orthogonally which skews the data once more. Still it performs a lot better than doing nothing (for my application anyway).