sfdipfilter filters input data based on a range of dips (slopes).
sfdipfilter operates in 2-D or 3-D Fourier transform domain, with the dimensionality specified by dim=. The dip range is specified either by angles (if angle=y) or by velocities (if angle=n). The four parameters (either ang1=, ang2=, ang3=, ang4= or v1=, v2=, v3=, v4=) specify the range. If pass=y, the range between v2 and v3 is passed, and the range below v1 or above v4 is rejected. If pass=n, the range between v2 and v3 is rejected, and the range below v1 or above v4 is passed. The transition between pass and reject regions is implemented with a sine tapering.