Seismic Preconditioners

Model topmute

Create a linear operator for a 2D model topmute, i.e. for muting the water column:

Mr = judiTopmute(n, mute_start, length)

Parameters:

• n: Tuple of model dimensions (e.g. from model.n)

• mute_start: First grid point in z-direction from where on to mute the image. Can be a single integer or a vector of length nx, where nx is the number of grid points in x direction.

• length: The mask is created with a linear taper from 0 to 1. The width of the taper is length.

Usage:

# Forward
m_mute = Mr*vec(m)

# Adjoint
m_mute = Mr'*vec(m)

As Mr is self adjoint, Mr is equal to Mr'.

Model depth scaling

Create a 2D model depth scaling:

Mr = judiDepthScaling(model)

Parameters:

• model: JUDI Model structure.

Data topmute (experimental)

Create a data topmute for a 2D marine shot record (i.e. for a shot record with an end-on-spread acquisition geometry).

Ml = judiMarineTopmute2D(muteStart, geometry; flipmask=false)

Parameters:

• muteStart: Vertical index of the apex of the shot record (i.e. the earliest point from where to mute).

• geometry: A JUDI Geometry object with the receiver geometry.

• flipmask: If the source is on the left side, set to false (default). If the source is on the right side, set to true.