Low-pass (LPAS)

Use the Low-pass option to apply the low-pass filter.

Low-pass Filter dialog options

Cutoff wavelength

The cutoff wavelength in ground units k0-1. All wavelengths shorter than this value are removed.

Application Notes

The low-pass filter can be used to pass or reject a range of wavelengths contained in the data. However, applying such a simple cutoff filter operator to an energy spectrum almost invariably introduces a significant amount of oscillation (also known as Gibbs’ Phenomenon). This filter is present for the sake of completeness. We recommend that you use a tapered filter such as the Butterworth filter (BTWR).

Low-pass

L(k) = 1	for k ≤ k0
L(k) = 0	for k > k0

Wavenumber domain variable definition

k	Wavenumber domain increment, used to depict a radially symmetrical variable.	where: np is the number of points cs is the cell size
u	X component in the wavenumber domain.	k = 2π ( i μ+j ν )
v	Y component in the wavenumber domain.
r	Radial component in the wavenumber domain.	also 2πk
θ	Polar component in the wavenumber domain.

Ground_unit is the survey ground units as defined in your grid (e.g. metre or feet). Ground units may be left undefined.